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* module loader dead code removal and cleanups v2
@ 2021-01-28 18:14 ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

Hi all,

this series removes support for long term unused export types and
cleans up various loose ends in the module loader.

Changes since v1:
 - move struct symsearch to module.c
 - rework drm to not call find_module at all
 - llow RCU-sched locking for find_module
 - keep find_module as a public API instead of module_loaded
 - update a few comments and commit logs

Diffstat:
 arch/arm/configs/bcm2835_defconfig          |    1 
 arch/arm/configs/mxs_defconfig              |    1 
 arch/mips/configs/nlm_xlp_defconfig         |    1 
 arch/mips/configs/nlm_xlr_defconfig         |    1 
 arch/parisc/configs/generic-32bit_defconfig |    1 
 arch/parisc/configs/generic-64bit_defconfig |    1 
 arch/powerpc/configs/ppc6xx_defconfig       |    1 
 arch/powerpc/platforms/powernv/pci-cxl.c    |   22 -
 arch/s390/configs/debug_defconfig           |    1 
 arch/s390/configs/defconfig                 |    1 
 arch/sh/configs/edosk7760_defconfig         |    1 
 arch/sh/configs/sdk7780_defconfig           |    1 
 arch/x86/configs/i386_defconfig             |    1 
 arch/x86/configs/x86_64_defconfig           |    1 
 arch/x86/tools/relocs.c                     |    4 
 drivers/gpu/drm/drm_crtc_helper_internal.h  |   10 
 drivers/gpu/drm/drm_fb_helper.c             |   21 -
 drivers/gpu/drm/drm_kms_helper_common.c     |   25 +-
 include/asm-generic/vmlinux.lds.h           |   42 ---
 include/linux/export.h                      |    9 
 include/linux/kallsyms.h                    |   17 -
 include/linux/module.h                      |   48 ----
 init/Kconfig                                |   17 -
 kernel/kallsyms.c                           |    8 
 kernel/livepatch/core.c                     |   11 
 kernel/module.c                             |  310 +++++++++-------------------
 kernel/trace/trace_kprobe.c                 |    4 
 lib/bug.c                                   |    3 
 scripts/checkpatch.pl                       |    6 
 scripts/mod/modpost.c                       |   50 ----
 scripts/mod/modpost.h                       |    3 
 scripts/module.lds.S                        |    6 
 tools/include/linux/export.h                |    3 
 33 files changed, 142 insertions(+), 490 deletions(-)

^ permalink raw reply	[flat|nested] 69+ messages in thread

* module loader dead code removal and cleanups v2
@ 2021-01-28 18:14 ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

Hi all,

this series removes support for long term unused export types and
cleans up various loose ends in the module loader.

Changes since v1:
 - move struct symsearch to module.c
 - rework drm to not call find_module at all
 - llow RCU-sched locking for find_module
 - keep find_module as a public API instead of module_loaded
 - update a few comments and commit logs

Diffstat:
 arch/arm/configs/bcm2835_defconfig          |    1 
 arch/arm/configs/mxs_defconfig              |    1 
 arch/mips/configs/nlm_xlp_defconfig         |    1 
 arch/mips/configs/nlm_xlr_defconfig         |    1 
 arch/parisc/configs/generic-32bit_defconfig |    1 
 arch/parisc/configs/generic-64bit_defconfig |    1 
 arch/powerpc/configs/ppc6xx_defconfig       |    1 
 arch/powerpc/platforms/powernv/pci-cxl.c    |   22 -
 arch/s390/configs/debug_defconfig           |    1 
 arch/s390/configs/defconfig                 |    1 
 arch/sh/configs/edosk7760_defconfig         |    1 
 arch/sh/configs/sdk7780_defconfig           |    1 
 arch/x86/configs/i386_defconfig             |    1 
 arch/x86/configs/x86_64_defconfig           |    1 
 arch/x86/tools/relocs.c                     |    4 
 drivers/gpu/drm/drm_crtc_helper_internal.h  |   10 
 drivers/gpu/drm/drm_fb_helper.c             |   21 -
 drivers/gpu/drm/drm_kms_helper_common.c     |   25 +-
 include/asm-generic/vmlinux.lds.h           |   42 ---
 include/linux/export.h                      |    9 
 include/linux/kallsyms.h                    |   17 -
 include/linux/module.h                      |   48 ----
 init/Kconfig                                |   17 -
 kernel/kallsyms.c                           |    8 
 kernel/livepatch/core.c                     |   11 
 kernel/module.c                             |  310 +++++++++-------------------
 kernel/trace/trace_kprobe.c                 |    4 
 lib/bug.c                                   |    3 
 scripts/checkpatch.pl                       |    6 
 scripts/mod/modpost.c                       |   50 ----
 scripts/mod/modpost.h                       |    3 
 scripts/module.lds.S                        |    6 
 tools/include/linux/export.h                |    3 
 33 files changed, 142 insertions(+), 490 deletions(-)

^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 01/13] powerpc/powernv: remove get_cxl_module
  2021-01-28 18:14 ` Christoph Hellwig
@ 2021-01-28 18:14   ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

The static inline get_cxl_module function is entirely unused since commit
8bf6b91a5125a ("Revert "powerpc/powernv: Add support for the cxl kernel
api on the real phb"), so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
---
 arch/powerpc/platforms/powernv/pci-cxl.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-cxl.c b/arch/powerpc/platforms/powernv/pci-cxl.c
index 8c739c94ed28d6..53172862d23bd3 100644
--- a/arch/powerpc/platforms/powernv/pci-cxl.c
+++ b/arch/powerpc/platforms/powernv/pci-cxl.c
@@ -150,25 +150,3 @@ int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
 	return 0;
 }
 EXPORT_SYMBOL(pnv_cxl_ioda_msi_setup);
-
-#if IS_MODULE(CONFIG_CXL)
-static inline int get_cxl_module(void)
-{
-	struct module *cxl_module;
-
-	mutex_lock(&module_mutex);
-
-	cxl_module = find_module("cxl");
-	if (cxl_module)
-		__module_get(cxl_module);
-
-	mutex_unlock(&module_mutex);
-
-	if (!cxl_module)
-		return -ENODEV;
-
-	return 0;
-}
-#else
-static inline int get_cxl_module(void) { return 0; }
-#endif
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 01/13] powerpc/powernv: remove get_cxl_module
@ 2021-01-28 18:14   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

The static inline get_cxl_module function is entirely unused since commit
8bf6b91a5125a ("Revert "powerpc/powernv: Add support for the cxl kernel
api on the real phb"), so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
---
 arch/powerpc/platforms/powernv/pci-cxl.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-cxl.c b/arch/powerpc/platforms/powernv/pci-cxl.c
index 8c739c94ed28d6..53172862d23bd3 100644
--- a/arch/powerpc/platforms/powernv/pci-cxl.c
+++ b/arch/powerpc/platforms/powernv/pci-cxl.c
@@ -150,25 +150,3 @@ int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
 	return 0;
 }
 EXPORT_SYMBOL(pnv_cxl_ioda_msi_setup);
-
-#if IS_MODULE(CONFIG_CXL)
-static inline int get_cxl_module(void)
-{
-	struct module *cxl_module;
-
-	mutex_lock(&module_mutex);
-
-	cxl_module = find_module("cxl");
-	if (cxl_module)
-		__module_get(cxl_module);
-
-	mutex_unlock(&module_mutex);
-
-	if (!cxl_module)
-		return -ENODEV;
-
-	return 0;
-}
-#else
-static inline int get_cxl_module(void) { return 0; }
-#endif
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 02/13] drm: remove drm_fb_helper_modinit
  2021-01-28 18:14 ` Christoph Hellwig
  (?)
  (?)
@ 2021-01-28 18:14 ` Christoph Hellwig
  2021-02-03 10:34     ` Daniel Vetter
  -1 siblings, 1 reply; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

drm_fb_helper_modinit has a lot of boilerplate for what is not very
simple functionality.  Just open code it in the only caller using
IS_ENABLED and IS_MODULE, and skip the find_module check as a
request_module is harmless if the module is already loaded (and not
other caller has this find_module check either).

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/gpu/drm/drm_crtc_helper_internal.h | 10 ---------
 drivers/gpu/drm/drm_fb_helper.c            | 21 ------------------
 drivers/gpu/drm/drm_kms_helper_common.c    | 25 +++++++++++-----------
 3 files changed, 12 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h b/drivers/gpu/drm/drm_crtc_helper_internal.h
index 25ce42e799952c..61e09f8a8d0ff0 100644
--- a/drivers/gpu/drm/drm_crtc_helper_internal.h
+++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
@@ -32,16 +32,6 @@
 #include <drm/drm_encoder.h>
 #include <drm/drm_modes.h>
 
-/* drm_fb_helper.c */
-#ifdef CONFIG_DRM_FBDEV_EMULATION
-int drm_fb_helper_modinit(void);
-#else
-static inline int drm_fb_helper_modinit(void)
-{
-	return 0;
-}
-#endif
-
 /* drm_dp_aux_dev.c */
 #ifdef CONFIG_DRM_DP_AUX_CHARDEV
 int drm_dp_aux_dev_init(void);
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 4b81195106875d..0b9f1ae1b7864c 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2499,24 +2499,3 @@ void drm_fbdev_generic_setup(struct drm_device *dev,
 	drm_client_register(&fb_helper->client);
 }
 EXPORT_SYMBOL(drm_fbdev_generic_setup);
-
-/* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
- * but the module doesn't depend on any fb console symbols.  At least
- * attempt to load fbcon to avoid leaving the system without a usable console.
- */
-int __init drm_fb_helper_modinit(void)
-{
-#if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
-	const char name[] = "fbcon";
-	struct module *fbcon;
-
-	mutex_lock(&module_mutex);
-	fbcon = find_module(name);
-	mutex_unlock(&module_mutex);
-
-	if (!fbcon)
-		request_module_nowait(name);
-#endif
-	return 0;
-}
-EXPORT_SYMBOL(drm_fb_helper_modinit);
diff --git a/drivers/gpu/drm/drm_kms_helper_common.c b/drivers/gpu/drm/drm_kms_helper_common.c
index 221a8528c9937a..f933da1656eb52 100644
--- a/drivers/gpu/drm/drm_kms_helper_common.c
+++ b/drivers/gpu/drm/drm_kms_helper_common.c
@@ -64,19 +64,18 @@ MODULE_PARM_DESC(edid_firmware,
 
 static int __init drm_kms_helper_init(void)
 {
-	int ret;
-
-	/* Call init functions from specific kms helpers here */
-	ret = drm_fb_helper_modinit();
-	if (ret < 0)
-		goto out;
-
-	ret = drm_dp_aux_dev_init();
-	if (ret < 0)
-		goto out;
-
-out:
-	return ret;
+	/*
+	 * The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
+	 * but the module doesn't depend on any fb console symbols.  At least
+	 * attempt to load fbcon to avoid leaving the system without a usable
+	 * console.
+	 */
+	if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) &&
+	    IS_MODULE(CONFIG_FRAMEBUFFER_CONSOLE) &&
+	    !IS_ENABLED(CONFIG_EXPERT))
+		request_module_nowait("fbcon");
+
+	return drm_dp_aux_dev_init();
 }
 
 static void __exit drm_kms_helper_exit(void)
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 03/13] module: unexport find_module and module_mutex
  2021-01-28 18:14 ` Christoph Hellwig
@ 2021-01-28 18:14   ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

find_module is not used by modular code any more, and random driver code
has no business calling it to start with.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/module.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 4bf30e4b3eaaa1..981302f616b411 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -88,7 +88,6 @@
  * (delete and add uses RCU list operations).
  */
 DEFINE_MUTEX(module_mutex);
-EXPORT_SYMBOL_GPL(module_mutex);
 static LIST_HEAD(modules);
 
 /* Work queue for freeing init sections in success case */
@@ -672,7 +671,6 @@ struct module *find_module(const char *name)
 	module_assert_mutex();
 	return find_module_all(name, strlen(name), false);
 }
-EXPORT_SYMBOL_GPL(find_module);
 
 #ifdef CONFIG_SMP
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 03/13] module: unexport find_module and module_mutex
@ 2021-01-28 18:14   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

find_module is not used by modular code any more, and random driver code
has no business calling it to start with.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/module.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 4bf30e4b3eaaa1..981302f616b411 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -88,7 +88,6 @@
  * (delete and add uses RCU list operations).
  */
 DEFINE_MUTEX(module_mutex);
-EXPORT_SYMBOL_GPL(module_mutex);
 static LIST_HEAD(modules);
 
 /* Work queue for freeing init sections in success case */
@@ -672,7 +671,6 @@ struct module *find_module(const char *name)
 	module_assert_mutex();
 	return find_module_all(name, strlen(name), false);
 }
-EXPORT_SYMBOL_GPL(find_module);
 
 #ifdef CONFIG_SMP
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 04/13] module: use RCU to synchronize find_module
  2021-01-28 18:14 ` Christoph Hellwig
@ 2021-01-28 18:14   ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

Allow for a RCU-sched critical section around find_module, following
the lower level find_module_all helper, and switch the two callers
outside of module.c to use such a RCU-sched critical section instead
of module_mutex.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/module.h      | 2 +-
 kernel/livepatch/core.c     | 5 +++--
 kernel/module.c             | 1 -
 kernel/trace/trace_kprobe.c | 4 ++--
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 7a0bcb5b1ffccd..a64aa84d1b182c 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -586,7 +586,7 @@ static inline bool within_module(unsigned long addr, const struct module *mod)
 	return within_module_init(addr, mod) || within_module_core(addr, mod);
 }
 
-/* Search for module by name: must hold module_mutex. */
+/* Search for module by name: must be in a RCU-sched critical section. */
 struct module *find_module(const char *name);
 
 struct symsearch {
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index f76fdb9255323d..262cd9b003b9f0 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -19,6 +19,7 @@
 #include <linux/moduleloader.h>
 #include <linux/completion.h>
 #include <linux/memory.h>
+#include <linux/rcupdate.h>
 #include <asm/cacheflush.h>
 #include "core.h"
 #include "patch.h"
@@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object *obj)
 	if (!klp_is_module(obj))
 		return;
 
-	mutex_lock(&module_mutex);
+	rcu_read_lock_sched();
 	/*
 	 * We do not want to block removal of patched modules and therefore
 	 * we do not take a reference here. The patches are removed by
@@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj)
 	if (mod && mod->klp_alive)
 		obj->mod = mod;
 
-	mutex_unlock(&module_mutex);
+	rcu_read_unlock_sched();
 }
 
 static bool klp_initialized(void)
diff --git a/kernel/module.c b/kernel/module.c
index 981302f616b411..6772fb2680eb3e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -668,7 +668,6 @@ static struct module *find_module_all(const char *name, size_t len,
 
 struct module *find_module(const char *name)
 {
-	module_assert_mutex();
 	return find_module_all(name, strlen(name), false);
 }
 
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index e6fba1798771b4..3137992baa5e7a 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -124,9 +124,9 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 	if (!p)
 		return true;
 	*p = '\0';
-	mutex_lock(&module_mutex);
+	rcu_read_lock_sched();
 	ret = !!find_module(tk->symbol);
-	mutex_unlock(&module_mutex);
+	rcu_read_unlock_sched();
 	*p = ':';
 
 	return ret;
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-01-28 18:14   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

Allow for a RCU-sched critical section around find_module, following
the lower level find_module_all helper, and switch the two callers
outside of module.c to use such a RCU-sched critical section instead
of module_mutex.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/module.h      | 2 +-
 kernel/livepatch/core.c     | 5 +++--
 kernel/module.c             | 1 -
 kernel/trace/trace_kprobe.c | 4 ++--
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 7a0bcb5b1ffccd..a64aa84d1b182c 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -586,7 +586,7 @@ static inline bool within_module(unsigned long addr, const struct module *mod)
 	return within_module_init(addr, mod) || within_module_core(addr, mod);
 }
 
-/* Search for module by name: must hold module_mutex. */
+/* Search for module by name: must be in a RCU-sched critical section. */
 struct module *find_module(const char *name);
 
 struct symsearch {
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index f76fdb9255323d..262cd9b003b9f0 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -19,6 +19,7 @@
 #include <linux/moduleloader.h>
 #include <linux/completion.h>
 #include <linux/memory.h>
+#include <linux/rcupdate.h>
 #include <asm/cacheflush.h>
 #include "core.h"
 #include "patch.h"
@@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object *obj)
 	if (!klp_is_module(obj))
 		return;
 
-	mutex_lock(&module_mutex);
+	rcu_read_lock_sched();
 	/*
 	 * We do not want to block removal of patched modules and therefore
 	 * we do not take a reference here. The patches are removed by
@@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj)
 	if (mod && mod->klp_alive)
 		obj->mod = mod;
 
-	mutex_unlock(&module_mutex);
+	rcu_read_unlock_sched();
 }
 
 static bool klp_initialized(void)
diff --git a/kernel/module.c b/kernel/module.c
index 981302f616b411..6772fb2680eb3e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -668,7 +668,6 @@ static struct module *find_module_all(const char *name, size_t len,
 
 struct module *find_module(const char *name)
 {
-	module_assert_mutex();
 	return find_module_all(name, strlen(name), false);
 }
 
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index e6fba1798771b4..3137992baa5e7a 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -124,9 +124,9 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 	if (!p)
 		return true;
 	*p = '\0';
-	mutex_lock(&module_mutex);
+	rcu_read_lock_sched();
 	ret = !!find_module(tk->symbol);
-	mutex_unlock(&module_mutex);
+	rcu_read_unlock_sched();
 	*p = ':';
 
 	return ret;
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
  2021-01-28 18:14 ` Christoph Hellwig
                   ` (4 preceding siblings ...)
  (?)
@ 2021-01-28 18:14 ` Christoph Hellwig
  2021-01-29  9:43   ` Petr Mladek
  2021-02-01 14:02     ` Miroslav Benes
  -1 siblings, 2 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

Require an explicit call to module_kallsyms_on_each_symbol to look
for symbols in modules instead of the call from kallsyms_on_each_symbol,
and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
of leaving that up to the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/kallsyms.c       | 6 +++++-
 kernel/livepatch/core.c | 6 +-----
 kernel/module.c         | 8 ++++----
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index fe9de067771c34..a0d3f0865916f9 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -177,6 +177,10 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+/*
+ * Iterate over all symbols in vmlinux.  For symbols from modules use
+ * module_kallsyms_on_each_symbol instead.
+ */
 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 				      unsigned long),
 			    void *data)
@@ -192,7 +196,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 		if (ret != 0)
 			return ret;
 	}
-	return module_kallsyms_on_each_symbol(fn, data);
+	return 0;
 }
 
 static unsigned long get_symbol_pos(unsigned long addr,
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 262cd9b003b9f0..f591dac5e86ef4 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -164,12 +164,8 @@ static int klp_find_object_symbol(const char *objname, const char *name,
 		.pos = sympos,
 	};
 
-	mutex_lock(&module_mutex);
-	if (objname)
+	if (objname || !kallsyms_on_each_symbol(klp_find_callback, &args))
 		module_kallsyms_on_each_symbol(klp_find_callback, &args);
-	else
-		kallsyms_on_each_symbol(klp_find_callback, &args);
-	mutex_unlock(&module_mutex);
 
 	/*
 	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;
diff --git a/kernel/module.c b/kernel/module.c
index 6772fb2680eb3e..ae9045c5292a78 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4379,8 +4379,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	unsigned int i;
 	int ret;
 
-	module_assert_mutex();
-
+	mutex_lock(&module_mutex);
 	list_for_each_entry(mod, &modules, list) {
 		/* We hold module_mutex: no need for rcu_dereference_sched */
 		struct mod_kallsyms *kallsyms = mod->kallsyms;
@@ -4396,10 +4395,11 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
 				 mod, kallsyms_symbol_value(sym));
 			if (ret != 0)
-				return ret;
+				break;
 		}
 	}
-	return 0;
+	mutex_unlock(&module_mutex);
+	return ret;
 }
 #endif /* CONFIG_KALLSYMS */
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 06/13] kallsyms: only build {, module_}kallsyms_on_each_symbol when required
  2021-01-28 18:14 ` Christoph Hellwig
                   ` (5 preceding siblings ...)
  (?)
@ 2021-01-28 18:14 ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

kallsyms_on_each_symbol and module_kallsyms_on_each_symbol are only used
by the livepatching code, so don't build them if livepatching is not
enabled.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/kallsyms.h | 17 ++++-------------
 include/linux/module.h   | 16 ++++------------
 kernel/kallsyms.c        |  2 ++
 kernel/module.c          |  2 ++
 4 files changed, 12 insertions(+), 25 deletions(-)

diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 481273f0c72d42..465060acc9816f 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -71,15 +71,14 @@ static inline void *dereference_symbol_descriptor(void *ptr)
 	return ptr;
 }
 
-#ifdef CONFIG_KALLSYMS
-/* Lookup the address for a symbol. Returns 0 if not found. */
-unsigned long kallsyms_lookup_name(const char *name);
-
-/* Call a function on each kallsyms symbol in the core kernel */
 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 				      unsigned long),
 			    void *data);
 
+#ifdef CONFIG_KALLSYMS
+/* Lookup the address for a symbol. Returns 0 if not found. */
+unsigned long kallsyms_lookup_name(const char *name);
+
 extern int kallsyms_lookup_size_offset(unsigned long addr,
 				  unsigned long *symbolsize,
 				  unsigned long *offset);
@@ -108,14 +107,6 @@ static inline unsigned long kallsyms_lookup_name(const char *name)
 	return 0;
 }
 
-static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *,
-						    struct module *,
-						    unsigned long),
-					  void *data)
-{
-	return 0;
-}
-
 static inline int kallsyms_lookup_size_offset(unsigned long addr,
 					      unsigned long *symbolsize,
 					      unsigned long *offset)
diff --git a/include/linux/module.h b/include/linux/module.h
index a64aa84d1b182c..3ea4ffae608f97 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -608,10 +608,6 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 /* Look for this name: can be of form module:name. */
 unsigned long module_kallsyms_lookup_name(const char *name);
 
-int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
-					     struct module *, unsigned long),
-				   void *data);
-
 extern void __noreturn __module_put_and_exit(struct module *mod,
 			long code);
 #define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code)
@@ -795,14 +791,6 @@ static inline unsigned long module_kallsyms_lookup_name(const char *name)
 	return 0;
 }
 
-static inline int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
-							   struct module *,
-							   unsigned long),
-						 void *data)
-{
-	return 0;
-}
-
 static inline int register_module_notifier(struct notifier_block *nb)
 {
 	/* no events will happen anyway, so this can always succeed */
@@ -891,4 +879,8 @@ static inline bool module_sig_ok(struct module *module)
 }
 #endif	/* CONFIG_MODULE_SIG */
 
+int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
+					     struct module *, unsigned long),
+				   void *data);
+
 #endif /* _LINUX_MODULE_H */
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index a0d3f0865916f9..8043a90aa50ed3 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -177,6 +177,7 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+#ifdef CONFIG_LIVEPATCH
 /*
  * Iterate over all symbols in vmlinux.  For symbols from modules use
  * module_kallsyms_on_each_symbol instead.
@@ -198,6 +199,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 	}
 	return 0;
 }
+#endif /* CONFIG_LIVEPATCH */
 
 static unsigned long get_symbol_pos(unsigned long addr,
 				    unsigned long *symbolsize,
diff --git a/kernel/module.c b/kernel/module.c
index ae9045c5292a78..856df9e17ff3d0 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4371,6 +4371,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
 	return ret;
 }
 
+#ifdef CONFIG_LIVEPATCH
 int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 					     struct module *, unsigned long),
 				   void *data)
@@ -4401,6 +4402,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	mutex_unlock(&module_mutex);
 	return ret;
 }
+#endif /* CONFIG_LIVEPATCH */
 #endif /* CONFIG_KALLSYMS */
 
 /* Maximum number of characters written by module_flags() */
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 07/13] module: mark module_mutex static
  2021-01-28 18:14 ` Christoph Hellwig
@ 2021-01-28 18:14   ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

Except for two lockdep asserts module_mutex is only used in module.c.
Remove the two asserts given that the functions they are in are not
exported and just called from the module code, and mark module_mutex
static.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/module.h | 2 --
 kernel/module.c        | 2 +-
 lib/bug.c              | 3 ---
 3 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 3ea4ffae608f97..0f360c48fe92a6 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -550,8 +550,6 @@ static inline unsigned long kallsyms_symbol_value(const Elf_Sym *sym)
 }
 #endif
 
-extern struct mutex module_mutex;
-
 /* FIXME: It'd be nice to isolate modules during init, too, so they
    aren't used before they (may) fail.  But presently too much code
    (IDE & SCSI) require entry into the module during init.*/
diff --git a/kernel/module.c b/kernel/module.c
index 856df9e17ff3d0..5152fae1fc9406 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -87,7 +87,7 @@
  * 3) module_addr_min/module_addr_max.
  * (delete and add uses RCU list operations).
  */
-DEFINE_MUTEX(module_mutex);
+static DEFINE_MUTEX(module_mutex);
 static LIST_HEAD(modules);
 
 /* Work queue for freeing init sections in success case */
diff --git a/lib/bug.c b/lib/bug.c
index 7103440c0ee1af..8f9d537bfb2a59 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -91,8 +91,6 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 	char *secstrings;
 	unsigned int i;
 
-	lockdep_assert_held(&module_mutex);
-
 	mod->bug_table = NULL;
 	mod->num_bugs = 0;
 
@@ -118,7 +116,6 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 
 void module_bug_cleanup(struct module *mod)
 {
-	lockdep_assert_held(&module_mutex);
 	list_del_rcu(&mod->bug_list);
 }
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 07/13] module: mark module_mutex static
@ 2021-01-28 18:14   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

Except for two lockdep asserts module_mutex is only used in module.c.
Remove the two asserts given that the functions they are in are not
exported and just called from the module code, and mark module_mutex
static.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/module.h | 2 --
 kernel/module.c        | 2 +-
 lib/bug.c              | 3 ---
 3 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 3ea4ffae608f97..0f360c48fe92a6 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -550,8 +550,6 @@ static inline unsigned long kallsyms_symbol_value(const Elf_Sym *sym)
 }
 #endif
 
-extern struct mutex module_mutex;
-
 /* FIXME: It'd be nice to isolate modules during init, too, so they
    aren't used before they (may) fail.  But presently too much code
    (IDE & SCSI) require entry into the module during init.*/
diff --git a/kernel/module.c b/kernel/module.c
index 856df9e17ff3d0..5152fae1fc9406 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -87,7 +87,7 @@
  * 3) module_addr_min/module_addr_max.
  * (delete and add uses RCU list operations).
  */
-DEFINE_MUTEX(module_mutex);
+static DEFINE_MUTEX(module_mutex);
 static LIST_HEAD(modules);
 
 /* Work queue for freeing init sections in success case */
diff --git a/lib/bug.c b/lib/bug.c
index 7103440c0ee1af..8f9d537bfb2a59 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -91,8 +91,6 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 	char *secstrings;
 	unsigned int i;
 
-	lockdep_assert_held(&module_mutex);
-
 	mod->bug_table = NULL;
 	mod->num_bugs = 0;
 
@@ -118,7 +116,6 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 
 void module_bug_cleanup(struct module *mod)
 {
-	lockdep_assert_held(&module_mutex);
 	list_del_rcu(&mod->bug_list);
 }
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 08/13] module: remove each_symbol_in_section
  2021-01-28 18:14 ` Christoph Hellwig
                   ` (7 preceding siblings ...)
  (?)
@ 2021-01-28 18:14 ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

each_symbol_in_section just contains a trivial loop over its arguments.
Just open code the loop in the two callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/module.c | 29 +++++++----------------------
 1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 5152fae1fc9406..945fe94b81fd92 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -433,30 +433,13 @@ extern const s32 __start___kcrctab_unused_gpl[];
 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
 #endif
 
-static bool each_symbol_in_section(const struct symsearch *arr,
-				   unsigned int arrsize,
-				   struct module *owner,
-				   bool (*fn)(const struct symsearch *syms,
-					      struct module *owner,
-					      void *data),
-				   void *data)
-{
-	unsigned int j;
-
-	for (j = 0; j < arrsize; j++) {
-		if (fn(&arr[j], owner, data))
-			return true;
-	}
-
-	return false;
-}
-
 /* Returns true as soon as fn returns true, otherwise false. */
 static bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
 				    struct module *owner,
 				    void *data),
 			 void *data)
 {
+	unsigned int i;
 	struct module *mod;
 	static const struct symsearch arr[] = {
 		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
@@ -479,8 +462,9 @@ static bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
 
 	module_assert_mutex_or_preempt();
 
-	if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
-		return true;
+	for (i = 0; i < ARRAY_SIZE(arr); i++)
+		if (fn(&arr[i], NULL, data))
+			return true;
 
 	list_for_each_entry_rcu(mod, &modules, list,
 				lockdep_is_held(&module_mutex)) {
@@ -509,8 +493,9 @@ static bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
 
-		if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
-			return true;
+		for (i = 0; i < ARRAY_SIZE(arr); i++)
+			if (fn(&arr[i], mod, data))
+				return true;
 	}
 	return false;
 }
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 09/13] module: merge each_symbol_section into find_symbol
  2021-01-28 18:14 ` Christoph Hellwig
                   ` (8 preceding siblings ...)
  (?)
@ 2021-01-28 18:14 ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

each_symbol_section is only called by find_symbol, so merge the two
functions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/module.c | 148 ++++++++++++++++++++++--------------------------
 1 file changed, 69 insertions(+), 79 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 945fe94b81fd92..ff9045cc984b50 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -433,73 +433,6 @@ extern const s32 __start___kcrctab_unused_gpl[];
 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
 #endif
 
-/* Returns true as soon as fn returns true, otherwise false. */
-static bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
-				    struct module *owner,
-				    void *data),
-			 void *data)
-{
-	unsigned int i;
-	struct module *mod;
-	static const struct symsearch arr[] = {
-		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
-		  NOT_GPL_ONLY, false },
-		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
-		  __start___kcrctab_gpl,
-		  GPL_ONLY, false },
-		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
-		  __start___kcrctab_gpl_future,
-		  WILL_BE_GPL_ONLY, false },
-#ifdef CONFIG_UNUSED_SYMBOLS
-		{ __start___ksymtab_unused, __stop___ksymtab_unused,
-		  __start___kcrctab_unused,
-		  NOT_GPL_ONLY, true },
-		{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
-		  __start___kcrctab_unused_gpl,
-		  GPL_ONLY, true },
-#endif
-	};
-
-	module_assert_mutex_or_preempt();
-
-	for (i = 0; i < ARRAY_SIZE(arr); i++)
-		if (fn(&arr[i], NULL, data))
-			return true;
-
-	list_for_each_entry_rcu(mod, &modules, list,
-				lockdep_is_held(&module_mutex)) {
-		struct symsearch arr[] = {
-			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
-			  NOT_GPL_ONLY, false },
-			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
-			  mod->gpl_crcs,
-			  GPL_ONLY, false },
-			{ mod->gpl_future_syms,
-			  mod->gpl_future_syms + mod->num_gpl_future_syms,
-			  mod->gpl_future_crcs,
-			  WILL_BE_GPL_ONLY, false },
-#ifdef CONFIG_UNUSED_SYMBOLS
-			{ mod->unused_syms,
-			  mod->unused_syms + mod->num_unused_syms,
-			  mod->unused_crcs,
-			  NOT_GPL_ONLY, true },
-			{ mod->unused_gpl_syms,
-			  mod->unused_gpl_syms + mod->num_unused_gpl_syms,
-			  mod->unused_gpl_crcs,
-			  GPL_ONLY, true },
-#endif
-		};
-
-		if (mod->state == MODULE_STATE_UNFORMED)
-			continue;
-
-		for (i = 0; i < ARRAY_SIZE(arr); i++)
-			if (fn(&arr[i], mod, data))
-				return true;
-	}
-	return false;
-}
-
 struct find_symbol_arg {
 	/* Input */
 	const char *name;
@@ -610,24 +543,81 @@ static const struct kernel_symbol *find_symbol(const char *name,
 					bool gplok,
 					bool warn)
 {
-	struct find_symbol_arg fsa;
+	static const struct symsearch arr[] = {
+		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
+		  NOT_GPL_ONLY, false },
+		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
+		  __start___kcrctab_gpl,
+		  GPL_ONLY, false },
+		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
+		  __start___kcrctab_gpl_future,
+		  WILL_BE_GPL_ONLY, false },
+#ifdef CONFIG_UNUSED_SYMBOLS
+		{ __start___ksymtab_unused, __stop___ksymtab_unused,
+		  __start___kcrctab_unused,
+		  NOT_GPL_ONLY, true },
+		{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
+		  __start___kcrctab_unused_gpl,
+		  GPL_ONLY, true },
+#endif
+	};
+	struct find_symbol_arg fsa = {
+		.name = name,
+		.gplok = gplok,
+		.warn = warn,
+	};
+	struct module *mod;
+	unsigned int i;
+
+	module_assert_mutex_or_preempt();
+
+	for (i = 0; i < ARRAY_SIZE(arr); i++)
+		if (find_exported_symbol_in_section(&arr[i], NULL, &fsa))
+			goto found;
 
-	fsa.name = name;
-	fsa.gplok = gplok;
-	fsa.warn = warn;
+	list_for_each_entry_rcu(mod, &modules, list,
+				lockdep_is_held(&module_mutex)) {
+		struct symsearch arr[] = {
+			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
+			  NOT_GPL_ONLY, false },
+			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
+			  mod->gpl_crcs,
+			  GPL_ONLY, false },
+			{ mod->gpl_future_syms,
+			  mod->gpl_future_syms + mod->num_gpl_future_syms,
+			  mod->gpl_future_crcs,
+			  WILL_BE_GPL_ONLY, false },
+#ifdef CONFIG_UNUSED_SYMBOLS
+			{ mod->unused_syms,
+			  mod->unused_syms + mod->num_unused_syms,
+			  mod->unused_crcs,
+			  NOT_GPL_ONLY, true },
+			{ mod->unused_gpl_syms,
+			  mod->unused_gpl_syms + mod->num_unused_gpl_syms,
+			  mod->unused_gpl_crcs,
+			  GPL_ONLY, true },
+#endif
+		};
 
-	if (each_symbol_section(find_exported_symbol_in_section, &fsa)) {
-		if (owner)
-			*owner = fsa.owner;
-		if (crc)
-			*crc = fsa.crc;
-		if (license)
-			*license = fsa.license;
-		return fsa.sym;
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+
+		for (i = 0; i < ARRAY_SIZE(arr); i++)
+			if (find_exported_symbol_in_section(&arr[i], mod, &fsa))
+				goto found;
 	}
 
 	pr_debug("Failed to find symbol %s\n", name);
 	return NULL;
+
+found:
+	if (owner)
+		*owner = fsa.owner;
+	if (crc)
+		*crc = fsa.crc;
+	if (license)
+		*license = fsa.license;
+	return fsa.sym;
 }
 
 /*
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 10/13] module: pass struct find_symbol_args to find_symbol
  2021-01-28 18:14 ` Christoph Hellwig
@ 2021-01-28 18:14   ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

Simplify the calling convention by passing the find_symbol_args structure
to find_symbol instead of initializing it inside the function.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/module.c | 113 ++++++++++++++++++++++--------------------------
 1 file changed, 52 insertions(+), 61 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index ff9045cc984b50..f1441d39c015f5 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -536,12 +536,7 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms,
  * Find an exported symbol and return it, along with, (optional) crc and
  * (optional) module which owns it.  Needs preempt disabled or module_mutex.
  */
-static const struct kernel_symbol *find_symbol(const char *name,
-					struct module **owner,
-					const s32 **crc,
-					enum mod_license *license,
-					bool gplok,
-					bool warn)
+static bool find_symbol(struct find_symbol_arg *fsa)
 {
 	static const struct symsearch arr[] = {
 		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
@@ -561,19 +556,14 @@ static const struct kernel_symbol *find_symbol(const char *name,
 		  GPL_ONLY, true },
 #endif
 	};
-	struct find_symbol_arg fsa = {
-		.name = name,
-		.gplok = gplok,
-		.warn = warn,
-	};
 	struct module *mod;
 	unsigned int i;
 
 	module_assert_mutex_or_preempt();
 
 	for (i = 0; i < ARRAY_SIZE(arr); i++)
-		if (find_exported_symbol_in_section(&arr[i], NULL, &fsa))
-			goto found;
+		if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
+			return true;
 
 	list_for_each_entry_rcu(mod, &modules, list,
 				lockdep_is_held(&module_mutex)) {
@@ -603,21 +593,12 @@ static const struct kernel_symbol *find_symbol(const char *name,
 			continue;
 
 		for (i = 0; i < ARRAY_SIZE(arr); i++)
-			if (find_exported_symbol_in_section(&arr[i], mod, &fsa))
-				goto found;
+			if (find_exported_symbol_in_section(&arr[i], mod, fsa))
+				return true;
 	}
 
-	pr_debug("Failed to find symbol %s\n", name);
-	return NULL;
-
-found:
-	if (owner)
-		*owner = fsa.owner;
-	if (crc)
-		*crc = fsa.crc;
-	if (license)
-		*license = fsa.license;
-	return fsa.sym;
+	pr_debug("Failed to find symbol %s\n", fsa->name);
+	return false;
 }
 
 /*
@@ -1079,12 +1060,15 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod)
 
 void __symbol_put(const char *symbol)
 {
-	struct module *owner;
+	struct find_symbol_arg fsa = {
+		.name	= symbol,
+		.gplok	= true,
+	};
 
 	preempt_disable();
-	if (!find_symbol(symbol, &owner, NULL, NULL, true, false))
+	if (!find_symbol(&fsa))
 		BUG();
-	module_put(owner);
+	module_put(fsa.owner);
 	preempt_enable();
 }
 EXPORT_SYMBOL(__symbol_put);
@@ -1353,19 +1337,22 @@ static int check_version(const struct load_info *info,
 static inline int check_modstruct_version(const struct load_info *info,
 					  struct module *mod)
 {
-	const s32 *crc;
+	struct find_symbol_arg fsa = {
+		.name	= "module_layout",
+		.gplok	= true,
+	};
 
 	/*
 	 * Since this should be found in kernel (which can't be removed), no
 	 * locking is necessary -- use preempt_disable() to placate lockdep.
 	 */
 	preempt_disable();
-	if (!find_symbol("module_layout", NULL, &crc, NULL, true, false)) {
+	if (!find_symbol(&fsa)) {
 		preempt_enable();
 		BUG();
 	}
 	preempt_enable();
-	return check_version(info, "module_layout", mod, crc);
+	return check_version(info, "module_layout", mod, fsa.crc);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */
@@ -1459,10 +1446,11 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 						  const char *name,
 						  char ownername[])
 {
-	struct module *owner;
-	const struct kernel_symbol *sym;
-	const s32 *crc;
-	enum mod_license license;
+	struct find_symbol_arg fsa = {
+		.name	= name,
+		.gplok	= !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
+		.warn	= true,
+	};
 	int err;
 
 	/*
@@ -1472,42 +1460,40 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 	 */
 	sched_annotate_sleep();
 	mutex_lock(&module_mutex);
-	sym = find_symbol(name, &owner, &crc, &license,
-			  !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
-	if (!sym)
+	if (!find_symbol(&fsa))
 		goto unlock;
 
-	if (license == GPL_ONLY)
+	if (fsa.license == GPL_ONLY)
 		mod->using_gplonly_symbols = true;
 
-	if (!inherit_taint(mod, owner)) {
-		sym = NULL;
+	if (!inherit_taint(mod, fsa.owner)) {
+		fsa.sym = NULL;
 		goto getname;
 	}
 
-	if (!check_version(info, name, mod, crc)) {
-		sym = ERR_PTR(-EINVAL);
+	if (!check_version(info, name, mod, fsa.crc)) {
+		fsa.sym = ERR_PTR(-EINVAL);
 		goto getname;
 	}
 
-	err = verify_namespace_is_imported(info, sym, mod);
+	err = verify_namespace_is_imported(info, fsa.sym, mod);
 	if (err) {
-		sym = ERR_PTR(err);
+		fsa.sym = ERR_PTR(err);
 		goto getname;
 	}
 
-	err = ref_module(mod, owner);
+	err = ref_module(mod, fsa.owner);
 	if (err) {
-		sym = ERR_PTR(err);
+		fsa.sym = ERR_PTR(err);
 		goto getname;
 	}
 
 getname:
 	/* We must make copy under the lock if we failed to get ref. */
-	strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
+	strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
 unlock:
 	mutex_unlock(&module_mutex);
-	return sym;
+	return fsa.sym;
 }
 
 static const struct kernel_symbol *
@@ -2268,16 +2254,19 @@ static void free_module(struct module *mod)
 
 void *__symbol_get(const char *symbol)
 {
-	struct module *owner;
-	const struct kernel_symbol *sym;
+	struct find_symbol_arg fsa = {
+		.name	= symbol,
+		.gplok	= true,
+		.warn	= true,
+	};
 
 	preempt_disable();
-	sym = find_symbol(symbol, &owner, NULL, NULL, true, true);
-	if (sym && strong_try_module_get(owner))
-		sym = NULL;
+	if (!find_symbol(&fsa) || !strong_try_module_get(fsa.owner)) {
+		preempt_enable();
+		return NULL;
+	}
 	preempt_enable();
-
-	return sym ? (void *)kernel_symbol_value(sym) : NULL;
+	return (void *)kernel_symbol_value(fsa.sym);
 }
 EXPORT_SYMBOL_GPL(__symbol_get);
 
@@ -2290,7 +2279,6 @@ EXPORT_SYMBOL_GPL(__symbol_get);
 static int verify_exported_symbols(struct module *mod)
 {
 	unsigned int i;
-	struct module *owner;
 	const struct kernel_symbol *s;
 	struct {
 		const struct kernel_symbol *sym;
@@ -2307,12 +2295,15 @@ static int verify_exported_symbols(struct module *mod)
 
 	for (i = 0; i < ARRAY_SIZE(arr); i++) {
 		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
-			if (find_symbol(kernel_symbol_name(s), &owner, NULL,
-					NULL, true, false)) {
+			struct find_symbol_arg fsa = {
+				.name	= kernel_symbol_name(s),
+				.gplok	= true,
+			};
+			if (find_symbol(&fsa)) {
 				pr_err("%s: exports duplicate symbol %s"
 				       " (owned by %s)\n",
 				       mod->name, kernel_symbol_name(s),
-				       module_name(owner));
+				       module_name(fsa.owner));
 				return -ENOEXEC;
 			}
 		}
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 10/13] module: pass struct find_symbol_args to find_symbol
@ 2021-01-28 18:14   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

Simplify the calling convention by passing the find_symbol_args structure
to find_symbol instead of initializing it inside the function.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/module.c | 113 ++++++++++++++++++++++--------------------------
 1 file changed, 52 insertions(+), 61 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index ff9045cc984b50..f1441d39c015f5 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -536,12 +536,7 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms,
  * Find an exported symbol and return it, along with, (optional) crc and
  * (optional) module which owns it.  Needs preempt disabled or module_mutex.
  */
-static const struct kernel_symbol *find_symbol(const char *name,
-					struct module **owner,
-					const s32 **crc,
-					enum mod_license *license,
-					bool gplok,
-					bool warn)
+static bool find_symbol(struct find_symbol_arg *fsa)
 {
 	static const struct symsearch arr[] = {
 		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
@@ -561,19 +556,14 @@ static const struct kernel_symbol *find_symbol(const char *name,
 		  GPL_ONLY, true },
 #endif
 	};
-	struct find_symbol_arg fsa = {
-		.name = name,
-		.gplok = gplok,
-		.warn = warn,
-	};
 	struct module *mod;
 	unsigned int i;
 
 	module_assert_mutex_or_preempt();
 
 	for (i = 0; i < ARRAY_SIZE(arr); i++)
-		if (find_exported_symbol_in_section(&arr[i], NULL, &fsa))
-			goto found;
+		if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
+			return true;
 
 	list_for_each_entry_rcu(mod, &modules, list,
 				lockdep_is_held(&module_mutex)) {
@@ -603,21 +593,12 @@ static const struct kernel_symbol *find_symbol(const char *name,
 			continue;
 
 		for (i = 0; i < ARRAY_SIZE(arr); i++)
-			if (find_exported_symbol_in_section(&arr[i], mod, &fsa))
-				goto found;
+			if (find_exported_symbol_in_section(&arr[i], mod, fsa))
+				return true;
 	}
 
-	pr_debug("Failed to find symbol %s\n", name);
-	return NULL;
-
-found:
-	if (owner)
-		*owner = fsa.owner;
-	if (crc)
-		*crc = fsa.crc;
-	if (license)
-		*license = fsa.license;
-	return fsa.sym;
+	pr_debug("Failed to find symbol %s\n", fsa->name);
+	return false;
 }
 
 /*
@@ -1079,12 +1060,15 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod)
 
 void __symbol_put(const char *symbol)
 {
-	struct module *owner;
+	struct find_symbol_arg fsa = {
+		.name	= symbol,
+		.gplok	= true,
+	};
 
 	preempt_disable();
-	if (!find_symbol(symbol, &owner, NULL, NULL, true, false))
+	if (!find_symbol(&fsa))
 		BUG();
-	module_put(owner);
+	module_put(fsa.owner);
 	preempt_enable();
 }
 EXPORT_SYMBOL(__symbol_put);
@@ -1353,19 +1337,22 @@ static int check_version(const struct load_info *info,
 static inline int check_modstruct_version(const struct load_info *info,
 					  struct module *mod)
 {
-	const s32 *crc;
+	struct find_symbol_arg fsa = {
+		.name	= "module_layout",
+		.gplok	= true,
+	};
 
 	/*
 	 * Since this should be found in kernel (which can't be removed), no
 	 * locking is necessary -- use preempt_disable() to placate lockdep.
 	 */
 	preempt_disable();
-	if (!find_symbol("module_layout", NULL, &crc, NULL, true, false)) {
+	if (!find_symbol(&fsa)) {
 		preempt_enable();
 		BUG();
 	}
 	preempt_enable();
-	return check_version(info, "module_layout", mod, crc);
+	return check_version(info, "module_layout", mod, fsa.crc);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */
@@ -1459,10 +1446,11 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 						  const char *name,
 						  char ownername[])
 {
-	struct module *owner;
-	const struct kernel_symbol *sym;
-	const s32 *crc;
-	enum mod_license license;
+	struct find_symbol_arg fsa = {
+		.name	= name,
+		.gplok	= !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
+		.warn	= true,
+	};
 	int err;
 
 	/*
@@ -1472,42 +1460,40 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 	 */
 	sched_annotate_sleep();
 	mutex_lock(&module_mutex);
-	sym = find_symbol(name, &owner, &crc, &license,
-			  !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
-	if (!sym)
+	if (!find_symbol(&fsa))
 		goto unlock;
 
-	if (license == GPL_ONLY)
+	if (fsa.license == GPL_ONLY)
 		mod->using_gplonly_symbols = true;
 
-	if (!inherit_taint(mod, owner)) {
-		sym = NULL;
+	if (!inherit_taint(mod, fsa.owner)) {
+		fsa.sym = NULL;
 		goto getname;
 	}
 
-	if (!check_version(info, name, mod, crc)) {
-		sym = ERR_PTR(-EINVAL);
+	if (!check_version(info, name, mod, fsa.crc)) {
+		fsa.sym = ERR_PTR(-EINVAL);
 		goto getname;
 	}
 
-	err = verify_namespace_is_imported(info, sym, mod);
+	err = verify_namespace_is_imported(info, fsa.sym, mod);
 	if (err) {
-		sym = ERR_PTR(err);
+		fsa.sym = ERR_PTR(err);
 		goto getname;
 	}
 
-	err = ref_module(mod, owner);
+	err = ref_module(mod, fsa.owner);
 	if (err) {
-		sym = ERR_PTR(err);
+		fsa.sym = ERR_PTR(err);
 		goto getname;
 	}
 
 getname:
 	/* We must make copy under the lock if we failed to get ref. */
-	strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
+	strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
 unlock:
 	mutex_unlock(&module_mutex);
-	return sym;
+	return fsa.sym;
 }
 
 static const struct kernel_symbol *
@@ -2268,16 +2254,19 @@ static void free_module(struct module *mod)
 
 void *__symbol_get(const char *symbol)
 {
-	struct module *owner;
-	const struct kernel_symbol *sym;
+	struct find_symbol_arg fsa = {
+		.name	= symbol,
+		.gplok	= true,
+		.warn	= true,
+	};
 
 	preempt_disable();
-	sym = find_symbol(symbol, &owner, NULL, NULL, true, true);
-	if (sym && strong_try_module_get(owner))
-		sym = NULL;
+	if (!find_symbol(&fsa) || !strong_try_module_get(fsa.owner)) {
+		preempt_enable();
+		return NULL;
+	}
 	preempt_enable();
-
-	return sym ? (void *)kernel_symbol_value(sym) : NULL;
+	return (void *)kernel_symbol_value(fsa.sym);
 }
 EXPORT_SYMBOL_GPL(__symbol_get);
 
@@ -2290,7 +2279,6 @@ EXPORT_SYMBOL_GPL(__symbol_get);
 static int verify_exported_symbols(struct module *mod)
 {
 	unsigned int i;
-	struct module *owner;
 	const struct kernel_symbol *s;
 	struct {
 		const struct kernel_symbol *sym;
@@ -2307,12 +2295,15 @@ static int verify_exported_symbols(struct module *mod)
 
 	for (i = 0; i < ARRAY_SIZE(arr); i++) {
 		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
-			if (find_symbol(kernel_symbol_name(s), &owner, NULL,
-					NULL, true, false)) {
+			struct find_symbol_arg fsa = {
+				.name	= kernel_symbol_name(s),
+				.gplok	= true,
+			};
+			if (find_symbol(&fsa)) {
 				pr_err("%s: exports duplicate symbol %s"
 				       " (owned by %s)\n",
 				       mod->name, kernel_symbol_name(s),
-				       module_name(owner));
+				       module_name(fsa.owner));
 				return -ENOEXEC;
 			}
 		}
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 11/13] module: move struct symsearch to module.c
  2021-01-28 18:14 ` Christoph Hellwig
@ 2021-01-28 18:14   ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

struct symsearch is only used inside of module.h, so move the definition
out of module.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/module.h | 11 -----------
 kernel/module.c        | 11 +++++++++++
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 0f360c48fe92a6..da0f5966ee80c9 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -587,17 +587,6 @@ static inline bool within_module(unsigned long addr, const struct module *mod)
 /* Search for module by name: must be in a RCU-sched critical section. */
 struct module *find_module(const char *name);
 
-struct symsearch {
-	const struct kernel_symbol *start, *stop;
-	const s32 *crcs;
-	enum mod_license {
-		NOT_GPL_ONLY,
-		GPL_ONLY,
-		WILL_BE_GPL_ONLY,
-	} license;
-	bool unused;
-};
-
 /* Returns 0 and fills in value, defined and namebuf, or -ERANGE if
    symnum out of range. */
 int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
diff --git a/kernel/module.c b/kernel/module.c
index f1441d39c015f5..576c780e79c799 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -433,6 +433,17 @@ extern const s32 __start___kcrctab_unused_gpl[];
 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
 #endif
 
+struct symsearch {
+	const struct kernel_symbol *start, *stop;
+	const s32 *crcs;
+	enum mod_license {
+		NOT_GPL_ONLY,
+		GPL_ONLY,
+		WILL_BE_GPL_ONLY,
+	} license;
+	bool unused;
+};
+
 struct find_symbol_arg {
 	/* Input */
 	const char *name;
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 11/13] module: move struct symsearch to module.c
@ 2021-01-28 18:14   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

struct symsearch is only used inside of module.h, so move the definition
out of module.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/module.h | 11 -----------
 kernel/module.c        | 11 +++++++++++
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 0f360c48fe92a6..da0f5966ee80c9 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -587,17 +587,6 @@ static inline bool within_module(unsigned long addr, const struct module *mod)
 /* Search for module by name: must be in a RCU-sched critical section. */
 struct module *find_module(const char *name);
 
-struct symsearch {
-	const struct kernel_symbol *start, *stop;
-	const s32 *crcs;
-	enum mod_license {
-		NOT_GPL_ONLY,
-		GPL_ONLY,
-		WILL_BE_GPL_ONLY,
-	} license;
-	bool unused;
-};
-
 /* Returns 0 and fills in value, defined and namebuf, or -ERANGE if
    symnum out of range. */
 int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
diff --git a/kernel/module.c b/kernel/module.c
index f1441d39c015f5..576c780e79c799 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -433,6 +433,17 @@ extern const s32 __start___kcrctab_unused_gpl[];
 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
 #endif
 
+struct symsearch {
+	const struct kernel_symbol *start, *stop;
+	const s32 *crcs;
+	enum mod_license {
+		NOT_GPL_ONLY,
+		GPL_ONLY,
+		WILL_BE_GPL_ONLY,
+	} license;
+	bool unused;
+};
+
 struct find_symbol_arg {
 	/* Input */
 	const char *name;
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 12/13] module: remove EXPORT_SYMBOL_GPL_FUTURE
  2021-01-28 18:14 ` Christoph Hellwig
@ 2021-01-28 18:14   ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

As far as I can tell this has never been used at all, and certainly
not any time recently.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/tools/relocs.c           |  4 ++--
 include/asm-generic/vmlinux.lds.h | 14 --------------
 include/linux/export.h            |  1 -
 include/linux/module.h            |  5 -----
 kernel/module.c                   | 29 ++---------------------------
 scripts/mod/modpost.c             | 13 +------------
 scripts/mod/modpost.h             |  1 -
 scripts/module.lds.S              |  2 --
 tools/include/linux/export.h      |  1 -
 9 files changed, 5 insertions(+), 65 deletions(-)

diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index ce7188cbdae58a..0d210d0e83e241 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -61,8 +61,8 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
 	"__(start|end)_pci_.*|"
 	"__(start|end)_builtin_fw|"
-	"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
-	"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
+	"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl)|"
+	"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl)|"
 	"__(start|stop)___param|"
 	"__(start|stop)___modver|"
 	"__(start|stop)___bug_table|"
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index b2b3d81b1535a5..83243506e68b00 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -495,13 +495,6 @@
 		__stop___ksymtab_unused_gpl = .;			\
 	}								\
 									\
-	/* Kernel symbol table: GPL-future-only symbols */		\
-	__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
-		__start___ksymtab_gpl_future = .;			\
-		KEEP(*(SORT(___ksymtab_gpl_future+*)))			\
-		__stop___ksymtab_gpl_future = .;			\
-	}								\
-									\
 	/* Kernel symbol table: Normal symbols */			\
 	__kcrctab         : AT(ADDR(__kcrctab) - LOAD_OFFSET) {		\
 		__start___kcrctab = .;					\
@@ -530,13 +523,6 @@
 		__stop___kcrctab_unused_gpl = .;			\
 	}								\
 									\
-	/* Kernel symbol table: GPL-future-only symbols */		\
-	__kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \
-		__start___kcrctab_gpl_future = .;			\
-		KEEP(*(SORT(___kcrctab_gpl_future+*)))			\
-		__stop___kcrctab_gpl_future = .;			\
-	}								\
-									\
 	/* Kernel symbol table: strings */				\
         __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
 		*(__ksymtab_strings)					\
diff --git a/include/linux/export.h b/include/linux/export.h
index fceb5e85571711..362b64f8d4a7c2 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -157,7 +157,6 @@ struct kernel_symbol {
 
 #define EXPORT_SYMBOL(sym)		_EXPORT_SYMBOL(sym, "")
 #define EXPORT_SYMBOL_GPL(sym)		_EXPORT_SYMBOL(sym, "_gpl")
-#define EXPORT_SYMBOL_GPL_FUTURE(sym)	_EXPORT_SYMBOL(sym, "_gpl_future")
 #define EXPORT_SYMBOL_NS(sym, ns)	__EXPORT_SYMBOL(sym, "", #ns)
 #define EXPORT_SYMBOL_NS_GPL(sym, ns)	__EXPORT_SYMBOL(sym, "_gpl", #ns)
 
diff --git a/include/linux/module.h b/include/linux/module.h
index da0f5966ee80c9..e6e50ee3041238 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -411,11 +411,6 @@ struct module {
 
 	bool async_probe_requested;
 
-	/* symbols that will be GPL-only in the near future. */
-	const struct kernel_symbol *gpl_future_syms;
-	const s32 *gpl_future_crcs;
-	unsigned int num_gpl_future_syms;
-
 	/* Exception table */
 	unsigned int num_exentries;
 	struct exception_table_entry *extable;
diff --git a/kernel/module.c b/kernel/module.c
index 576c780e79c799..492b6fa5a662c8 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -413,11 +413,8 @@ extern const struct kernel_symbol __start___ksymtab[];
 extern const struct kernel_symbol __stop___ksymtab[];
 extern const struct kernel_symbol __start___ksymtab_gpl[];
 extern const struct kernel_symbol __stop___ksymtab_gpl[];
-extern const struct kernel_symbol __start___ksymtab_gpl_future[];
-extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
 extern const s32 __start___kcrctab[];
 extern const s32 __start___kcrctab_gpl[];
-extern const s32 __start___kcrctab_gpl_future[];
 #ifdef CONFIG_UNUSED_SYMBOLS
 extern const struct kernel_symbol __start___ksymtab_unused[];
 extern const struct kernel_symbol __stop___ksymtab_unused[];
@@ -439,7 +436,6 @@ struct symsearch {
 	enum mod_license {
 		NOT_GPL_ONLY,
 		GPL_ONLY,
-		WILL_BE_GPL_ONLY,
 	} license;
 	bool unused;
 };
@@ -463,15 +459,8 @@ static bool check_exported_symbol(const struct symsearch *syms,
 {
 	struct find_symbol_arg *fsa = data;
 
-	if (!fsa->gplok) {
-		if (syms->license == GPL_ONLY)
-			return false;
-		if (syms->license == WILL_BE_GPL_ONLY && fsa->warn) {
-			pr_warn("Symbol %s is being used by a non-GPL module, "
-				"which will not be allowed in the future\n",
-				fsa->name);
-		}
-	}
+	if (!fsa->gplok && syms->license == GPL_ONLY)
+		return false;
 
 #ifdef CONFIG_UNUSED_SYMBOLS
 	if (syms->unused && fsa->warn) {
@@ -555,9 +544,6 @@ static bool find_symbol(struct find_symbol_arg *fsa)
 		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
 		  __start___kcrctab_gpl,
 		  GPL_ONLY, false },
-		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
-		  __start___kcrctab_gpl_future,
-		  WILL_BE_GPL_ONLY, false },
 #ifdef CONFIG_UNUSED_SYMBOLS
 		{ __start___ksymtab_unused, __stop___ksymtab_unused,
 		  __start___kcrctab_unused,
@@ -584,10 +570,6 @@ static bool find_symbol(struct find_symbol_arg *fsa)
 			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
 			  mod->gpl_crcs,
 			  GPL_ONLY, false },
-			{ mod->gpl_future_syms,
-			  mod->gpl_future_syms + mod->num_gpl_future_syms,
-			  mod->gpl_future_crcs,
-			  WILL_BE_GPL_ONLY, false },
 #ifdef CONFIG_UNUSED_SYMBOLS
 			{ mod->unused_syms,
 			  mod->unused_syms + mod->num_unused_syms,
@@ -2297,7 +2279,6 @@ static int verify_exported_symbols(struct module *mod)
 	} arr[] = {
 		{ mod->syms, mod->num_syms },
 		{ mod->gpl_syms, mod->num_gpl_syms },
-		{ mod->gpl_future_syms, mod->num_gpl_future_syms },
 #ifdef CONFIG_UNUSED_SYMBOLS
 		{ mod->unused_syms, mod->num_unused_syms },
 		{ mod->unused_gpl_syms, mod->num_unused_gpl_syms },
@@ -3215,11 +3196,6 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 				     sizeof(*mod->gpl_syms),
 				     &mod->num_gpl_syms);
 	mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
-	mod->gpl_future_syms = section_objs(info,
-					    "__ksymtab_gpl_future",
-					    sizeof(*mod->gpl_future_syms),
-					    &mod->num_gpl_future_syms);
-	mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future");
 
 #ifdef CONFIG_UNUSED_SYMBOLS
 	mod->unused_syms = section_objs(info, "__ksymtab_unused",
@@ -3413,7 +3389,6 @@ static int check_module_license_and_versions(struct module *mod)
 #ifdef CONFIG_MODVERSIONS
 	if ((mod->num_syms && !mod->crcs)
 	    || (mod->num_gpl_syms && !mod->gpl_crcs)
-	    || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
 #ifdef CONFIG_UNUSED_SYMBOLS
 	    || (mod->num_unused_syms && !mod->unused_crcs)
 	    || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index d6c81657d69550..25c1446055d16b 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -44,7 +44,7 @@ static bool error_occurred;
 
 enum export {
 	export_plain,      export_unused,     export_gpl,
-	export_unused_gpl, export_gpl_future, export_unknown
+	export_unused_gpl, export_unknown
 };
 
 /* In kernel, this size is defined in linux/module.h;
@@ -304,7 +304,6 @@ static const struct {
 	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
 	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
-	{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
 	{ .str = "(unknown)",                .export = export_unknown },
 };
 
@@ -369,8 +368,6 @@ static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
 		return export_gpl;
 	else if (strstarts(secname, "___ksymtab_unused_gpl+"))
 		return export_unused_gpl;
-	else if (strstarts(secname, "___ksymtab_gpl_future+"))
-		return export_gpl_future;
 	else
 		return export_unknown;
 }
@@ -385,8 +382,6 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 		return export_gpl;
 	else if (sec == elf->export_unused_gpl_sec)
 		return export_unused_gpl;
-	else if (sec == elf->export_gpl_future_sec)
-		return export_gpl_future;
 	else
 		return export_unknown;
 }
@@ -596,8 +591,6 @@ static int parse_elf(struct elf_info *info, const char *filename)
 			info->export_gpl_sec = i;
 		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
 			info->export_unused_gpl_sec = i;
-		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
-			info->export_gpl_future_sec = i;
 
 		if (sechdrs[i].sh_type == SHT_SYMTAB) {
 			unsigned int sh_link_idx;
@@ -2152,10 +2145,6 @@ static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
 		error("GPL-incompatible module %s.ko uses GPL-only symbol marked UNUSED '%s'\n",
 		      m, s);
 		break;
-	case export_gpl_future:
-		warn("GPL-incompatible module %s.ko uses future GPL-only symbol '%s'\n",
-		     m, s);
-		break;
 	case export_plain:
 	case export_unused:
 	case export_unknown:
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index e6f46eee0af02f..834220de002bd1 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -142,7 +142,6 @@ struct elf_info {
 	Elf_Section  export_unused_sec;
 	Elf_Section  export_gpl_sec;
 	Elf_Section  export_unused_gpl_sec;
-	Elf_Section  export_gpl_future_sec;
 	char         *strtab;
 	char	     *modinfo;
 	unsigned int modinfo_len;
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index 69b9b71a6a4731..d82b452e8a7168 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -13,12 +13,10 @@ SECTIONS {
 	__ksymtab_gpl		0 : { *(SORT(___ksymtab_gpl+*)) }
 	__ksymtab_unused	0 : { *(SORT(___ksymtab_unused+*)) }
 	__ksymtab_unused_gpl	0 : { *(SORT(___ksymtab_unused_gpl+*)) }
-	__ksymtab_gpl_future	0 : { *(SORT(___ksymtab_gpl_future+*)) }
 	__kcrctab		0 : { *(SORT(___kcrctab+*)) }
 	__kcrctab_gpl		0 : { *(SORT(___kcrctab_gpl+*)) }
 	__kcrctab_unused	0 : { *(SORT(___kcrctab_unused+*)) }
 	__kcrctab_unused_gpl	0 : { *(SORT(___kcrctab_unused_gpl+*)) }
-	__kcrctab_gpl_future	0 : { *(SORT(___kcrctab_gpl_future+*)) }
 
 	.init_array		0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }
 
diff --git a/tools/include/linux/export.h b/tools/include/linux/export.h
index d07e586b9ba0ec..9f61349a8944e1 100644
--- a/tools/include/linux/export.h
+++ b/tools/include/linux/export.h
@@ -3,7 +3,6 @@
 
 #define EXPORT_SYMBOL(sym)
 #define EXPORT_SYMBOL_GPL(sym)
-#define EXPORT_SYMBOL_GPL_FUTURE(sym)
 #define EXPORT_UNUSED_SYMBOL(sym)
 #define EXPORT_UNUSED_SYMBOL_GPL(sym)
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 12/13] module: remove EXPORT_SYMBOL_GPL_FUTURE
@ 2021-01-28 18:14   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

As far as I can tell this has never been used at all, and certainly
not any time recently.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/tools/relocs.c           |  4 ++--
 include/asm-generic/vmlinux.lds.h | 14 --------------
 include/linux/export.h            |  1 -
 include/linux/module.h            |  5 -----
 kernel/module.c                   | 29 ++---------------------------
 scripts/mod/modpost.c             | 13 +------------
 scripts/mod/modpost.h             |  1 -
 scripts/module.lds.S              |  2 --
 tools/include/linux/export.h      |  1 -
 9 files changed, 5 insertions(+), 65 deletions(-)

diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index ce7188cbdae58a..0d210d0e83e241 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -61,8 +61,8 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
 	"__(start|end)_pci_.*|"
 	"__(start|end)_builtin_fw|"
-	"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
-	"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
+	"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl)|"
+	"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl)|"
 	"__(start|stop)___param|"
 	"__(start|stop)___modver|"
 	"__(start|stop)___bug_table|"
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index b2b3d81b1535a5..83243506e68b00 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -495,13 +495,6 @@
 		__stop___ksymtab_unused_gpl = .;			\
 	}								\
 									\
-	/* Kernel symbol table: GPL-future-only symbols */		\
-	__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
-		__start___ksymtab_gpl_future = .;			\
-		KEEP(*(SORT(___ksymtab_gpl_future+*)))			\
-		__stop___ksymtab_gpl_future = .;			\
-	}								\
-									\
 	/* Kernel symbol table: Normal symbols */			\
 	__kcrctab         : AT(ADDR(__kcrctab) - LOAD_OFFSET) {		\
 		__start___kcrctab = .;					\
@@ -530,13 +523,6 @@
 		__stop___kcrctab_unused_gpl = .;			\
 	}								\
 									\
-	/* Kernel symbol table: GPL-future-only symbols */		\
-	__kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \
-		__start___kcrctab_gpl_future = .;			\
-		KEEP(*(SORT(___kcrctab_gpl_future+*)))			\
-		__stop___kcrctab_gpl_future = .;			\
-	}								\
-									\
 	/* Kernel symbol table: strings */				\
         __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
 		*(__ksymtab_strings)					\
diff --git a/include/linux/export.h b/include/linux/export.h
index fceb5e85571711..362b64f8d4a7c2 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -157,7 +157,6 @@ struct kernel_symbol {
 
 #define EXPORT_SYMBOL(sym)		_EXPORT_SYMBOL(sym, "")
 #define EXPORT_SYMBOL_GPL(sym)		_EXPORT_SYMBOL(sym, "_gpl")
-#define EXPORT_SYMBOL_GPL_FUTURE(sym)	_EXPORT_SYMBOL(sym, "_gpl_future")
 #define EXPORT_SYMBOL_NS(sym, ns)	__EXPORT_SYMBOL(sym, "", #ns)
 #define EXPORT_SYMBOL_NS_GPL(sym, ns)	__EXPORT_SYMBOL(sym, "_gpl", #ns)
 
diff --git a/include/linux/module.h b/include/linux/module.h
index da0f5966ee80c9..e6e50ee3041238 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -411,11 +411,6 @@ struct module {
 
 	bool async_probe_requested;
 
-	/* symbols that will be GPL-only in the near future. */
-	const struct kernel_symbol *gpl_future_syms;
-	const s32 *gpl_future_crcs;
-	unsigned int num_gpl_future_syms;
-
 	/* Exception table */
 	unsigned int num_exentries;
 	struct exception_table_entry *extable;
diff --git a/kernel/module.c b/kernel/module.c
index 576c780e79c799..492b6fa5a662c8 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -413,11 +413,8 @@ extern const struct kernel_symbol __start___ksymtab[];
 extern const struct kernel_symbol __stop___ksymtab[];
 extern const struct kernel_symbol __start___ksymtab_gpl[];
 extern const struct kernel_symbol __stop___ksymtab_gpl[];
-extern const struct kernel_symbol __start___ksymtab_gpl_future[];
-extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
 extern const s32 __start___kcrctab[];
 extern const s32 __start___kcrctab_gpl[];
-extern const s32 __start___kcrctab_gpl_future[];
 #ifdef CONFIG_UNUSED_SYMBOLS
 extern const struct kernel_symbol __start___ksymtab_unused[];
 extern const struct kernel_symbol __stop___ksymtab_unused[];
@@ -439,7 +436,6 @@ struct symsearch {
 	enum mod_license {
 		NOT_GPL_ONLY,
 		GPL_ONLY,
-		WILL_BE_GPL_ONLY,
 	} license;
 	bool unused;
 };
@@ -463,15 +459,8 @@ static bool check_exported_symbol(const struct symsearch *syms,
 {
 	struct find_symbol_arg *fsa = data;
 
-	if (!fsa->gplok) {
-		if (syms->license == GPL_ONLY)
-			return false;
-		if (syms->license == WILL_BE_GPL_ONLY && fsa->warn) {
-			pr_warn("Symbol %s is being used by a non-GPL module, "
-				"which will not be allowed in the future\n",
-				fsa->name);
-		}
-	}
+	if (!fsa->gplok && syms->license == GPL_ONLY)
+		return false;
 
 #ifdef CONFIG_UNUSED_SYMBOLS
 	if (syms->unused && fsa->warn) {
@@ -555,9 +544,6 @@ static bool find_symbol(struct find_symbol_arg *fsa)
 		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
 		  __start___kcrctab_gpl,
 		  GPL_ONLY, false },
-		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
-		  __start___kcrctab_gpl_future,
-		  WILL_BE_GPL_ONLY, false },
 #ifdef CONFIG_UNUSED_SYMBOLS
 		{ __start___ksymtab_unused, __stop___ksymtab_unused,
 		  __start___kcrctab_unused,
@@ -584,10 +570,6 @@ static bool find_symbol(struct find_symbol_arg *fsa)
 			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
 			  mod->gpl_crcs,
 			  GPL_ONLY, false },
-			{ mod->gpl_future_syms,
-			  mod->gpl_future_syms + mod->num_gpl_future_syms,
-			  mod->gpl_future_crcs,
-			  WILL_BE_GPL_ONLY, false },
 #ifdef CONFIG_UNUSED_SYMBOLS
 			{ mod->unused_syms,
 			  mod->unused_syms + mod->num_unused_syms,
@@ -2297,7 +2279,6 @@ static int verify_exported_symbols(struct module *mod)
 	} arr[] = {
 		{ mod->syms, mod->num_syms },
 		{ mod->gpl_syms, mod->num_gpl_syms },
-		{ mod->gpl_future_syms, mod->num_gpl_future_syms },
 #ifdef CONFIG_UNUSED_SYMBOLS
 		{ mod->unused_syms, mod->num_unused_syms },
 		{ mod->unused_gpl_syms, mod->num_unused_gpl_syms },
@@ -3215,11 +3196,6 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 				     sizeof(*mod->gpl_syms),
 				     &mod->num_gpl_syms);
 	mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
-	mod->gpl_future_syms = section_objs(info,
-					    "__ksymtab_gpl_future",
-					    sizeof(*mod->gpl_future_syms),
-					    &mod->num_gpl_future_syms);
-	mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future");
 
 #ifdef CONFIG_UNUSED_SYMBOLS
 	mod->unused_syms = section_objs(info, "__ksymtab_unused",
@@ -3413,7 +3389,6 @@ static int check_module_license_and_versions(struct module *mod)
 #ifdef CONFIG_MODVERSIONS
 	if ((mod->num_syms && !mod->crcs)
 	    || (mod->num_gpl_syms && !mod->gpl_crcs)
-	    || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
 #ifdef CONFIG_UNUSED_SYMBOLS
 	    || (mod->num_unused_syms && !mod->unused_crcs)
 	    || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index d6c81657d69550..25c1446055d16b 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -44,7 +44,7 @@ static bool error_occurred;
 
 enum export {
 	export_plain,      export_unused,     export_gpl,
-	export_unused_gpl, export_gpl_future, export_unknown
+	export_unused_gpl, export_unknown
 };
 
 /* In kernel, this size is defined in linux/module.h;
@@ -304,7 +304,6 @@ static const struct {
 	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
 	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
-	{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
 	{ .str = "(unknown)",                .export = export_unknown },
 };
 
@@ -369,8 +368,6 @@ static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
 		return export_gpl;
 	else if (strstarts(secname, "___ksymtab_unused_gpl+"))
 		return export_unused_gpl;
-	else if (strstarts(secname, "___ksymtab_gpl_future+"))
-		return export_gpl_future;
 	else
 		return export_unknown;
 }
@@ -385,8 +382,6 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 		return export_gpl;
 	else if (sec == elf->export_unused_gpl_sec)
 		return export_unused_gpl;
-	else if (sec == elf->export_gpl_future_sec)
-		return export_gpl_future;
 	else
 		return export_unknown;
 }
@@ -596,8 +591,6 @@ static int parse_elf(struct elf_info *info, const char *filename)
 			info->export_gpl_sec = i;
 		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
 			info->export_unused_gpl_sec = i;
-		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
-			info->export_gpl_future_sec = i;
 
 		if (sechdrs[i].sh_type == SHT_SYMTAB) {
 			unsigned int sh_link_idx;
@@ -2152,10 +2145,6 @@ static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
 		error("GPL-incompatible module %s.ko uses GPL-only symbol marked UNUSED '%s'\n",
 		      m, s);
 		break;
-	case export_gpl_future:
-		warn("GPL-incompatible module %s.ko uses future GPL-only symbol '%s'\n",
-		     m, s);
-		break;
 	case export_plain:
 	case export_unused:
 	case export_unknown:
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index e6f46eee0af02f..834220de002bd1 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -142,7 +142,6 @@ struct elf_info {
 	Elf_Section  export_unused_sec;
 	Elf_Section  export_gpl_sec;
 	Elf_Section  export_unused_gpl_sec;
-	Elf_Section  export_gpl_future_sec;
 	char         *strtab;
 	char	     *modinfo;
 	unsigned int modinfo_len;
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index 69b9b71a6a4731..d82b452e8a7168 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -13,12 +13,10 @@ SECTIONS {
 	__ksymtab_gpl		0 : { *(SORT(___ksymtab_gpl+*)) }
 	__ksymtab_unused	0 : { *(SORT(___ksymtab_unused+*)) }
 	__ksymtab_unused_gpl	0 : { *(SORT(___ksymtab_unused_gpl+*)) }
-	__ksymtab_gpl_future	0 : { *(SORT(___ksymtab_gpl_future+*)) }
 	__kcrctab		0 : { *(SORT(___kcrctab+*)) }
 	__kcrctab_gpl		0 : { *(SORT(___kcrctab_gpl+*)) }
 	__kcrctab_unused	0 : { *(SORT(___kcrctab_unused+*)) }
 	__kcrctab_unused_gpl	0 : { *(SORT(___kcrctab_unused_gpl+*)) }
-	__kcrctab_gpl_future	0 : { *(SORT(___kcrctab_gpl_future+*)) }
 
 	.init_array		0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }
 
diff --git a/tools/include/linux/export.h b/tools/include/linux/export.h
index d07e586b9ba0ec..9f61349a8944e1 100644
--- a/tools/include/linux/export.h
+++ b/tools/include/linux/export.h
@@ -3,7 +3,6 @@
 
 #define EXPORT_SYMBOL(sym)
 #define EXPORT_SYMBOL_GPL(sym)
-#define EXPORT_SYMBOL_GPL_FUTURE(sym)
 #define EXPORT_UNUSED_SYMBOL(sym)
 #define EXPORT_UNUSED_SYMBOL_GPL(sym)
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 13/13] module: remove EXPORT_UNUSED_SYMBOL*
  2021-01-28 18:14 ` Christoph Hellwig
                   ` (12 preceding siblings ...)
  (?)
@ 2021-01-28 18:14 ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-28 18:14 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

EXPORT_UNUSED_SYMBOL* is not actually used anywhere.  Remove the
unused functionality as we generally just remove unused code anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arm/configs/bcm2835_defconfig          |  1 -
 arch/arm/configs/mxs_defconfig              |  1 -
 arch/mips/configs/nlm_xlp_defconfig         |  1 -
 arch/mips/configs/nlm_xlr_defconfig         |  1 -
 arch/parisc/configs/generic-32bit_defconfig |  1 -
 arch/parisc/configs/generic-64bit_defconfig |  1 -
 arch/powerpc/configs/ppc6xx_defconfig       |  1 -
 arch/s390/configs/debug_defconfig           |  1 -
 arch/s390/configs/defconfig                 |  1 -
 arch/sh/configs/edosk7760_defconfig         |  1 -
 arch/sh/configs/sdk7780_defconfig           |  1 -
 arch/x86/configs/i386_defconfig             |  1 -
 arch/x86/configs/x86_64_defconfig           |  1 -
 arch/x86/tools/relocs.c                     |  4 +-
 include/asm-generic/vmlinux.lds.h           | 28 --------
 include/linux/export.h                      |  8 ---
 include/linux/module.h                      | 12 ----
 init/Kconfig                                | 17 -----
 kernel/module.c                             | 71 ++-------------------
 scripts/checkpatch.pl                       |  6 +-
 scripts/mod/modpost.c                       | 39 +----------
 scripts/mod/modpost.h                       |  2 -
 scripts/module.lds.S                        |  4 --
 tools/include/linux/export.h                |  2 -
 24 files changed, 13 insertions(+), 193 deletions(-)

diff --git a/arch/arm/configs/bcm2835_defconfig b/arch/arm/configs/bcm2835_defconfig
index 44ff9cd88d8161..d6c6c2e031c43a 100644
--- a/arch/arm/configs/bcm2835_defconfig
+++ b/arch/arm/configs/bcm2835_defconfig
@@ -177,7 +177,6 @@ CONFIG_BOOT_PRINTK_DELAY=y
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_MUST_CHECK is not set
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_MEMORY_INIT=y
 CONFIG_LOCKUP_DETECTOR=y
 CONFIG_SCHED_TRACER=y
diff --git a/arch/arm/configs/mxs_defconfig b/arch/arm/configs/mxs_defconfig
index a9c6f32a9b1c9d..ca32446b187f5d 100644
--- a/arch/arm/configs/mxs_defconfig
+++ b/arch/arm/configs/mxs_defconfig
@@ -164,7 +164,6 @@ CONFIG_FONTS=y
 CONFIG_PRINTK_TIME=y
 CONFIG_DEBUG_INFO=y
 CONFIG_FRAME_WARN=2048
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_SOFTLOCKUP_DETECTOR=y
diff --git a/arch/mips/configs/nlm_xlp_defconfig b/arch/mips/configs/nlm_xlp_defconfig
index 72a211d2d556fd..32c29061172325 100644
--- a/arch/mips/configs/nlm_xlp_defconfig
+++ b/arch/mips/configs/nlm_xlp_defconfig
@@ -549,7 +549,6 @@ CONFIG_PRINTK_TIME=y
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_FRAME_WARN=1024
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_MEMORY_INIT=y
 CONFIG_DETECT_HUNG_TASK=y
 CONFIG_SCHEDSTATS=y
diff --git a/arch/mips/configs/nlm_xlr_defconfig b/arch/mips/configs/nlm_xlr_defconfig
index 4ecb157e56d427..bf9b9244929ecd 100644
--- a/arch/mips/configs/nlm_xlr_defconfig
+++ b/arch/mips/configs/nlm_xlr_defconfig
@@ -500,7 +500,6 @@ CONFIG_CRC7=m
 CONFIG_PRINTK_TIME=y
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_MUST_CHECK is not set
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_MEMORY_INIT=y
 CONFIG_DETECT_HUNG_TASK=y
 CONFIG_SCHEDSTATS=y
diff --git a/arch/parisc/configs/generic-32bit_defconfig b/arch/parisc/configs/generic-32bit_defconfig
index 3cbcfad5f7249d..7611d48c599e01 100644
--- a/arch/parisc/configs/generic-32bit_defconfig
+++ b/arch/parisc/configs/generic-32bit_defconfig
@@ -22,7 +22,6 @@ CONFIG_PCI_LBA=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
-CONFIG_UNUSED_SYMBOLS=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 CONFIG_BINFMT_MISC=m
diff --git a/arch/parisc/configs/generic-64bit_defconfig b/arch/parisc/configs/generic-64bit_defconfig
index 8f81fcbf04c413..53054b81461a10 100644
--- a/arch/parisc/configs/generic-64bit_defconfig
+++ b/arch/parisc/configs/generic-64bit_defconfig
@@ -31,7 +31,6 @@ CONFIG_MODULE_FORCE_LOAD=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
 CONFIG_MODVERSIONS=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_BLK_DEV_INTEGRITY=y
 CONFIG_BINFMT_MISC=m
 # CONFIG_COMPACTION is not set
diff --git a/arch/powerpc/configs/ppc6xx_defconfig b/arch/powerpc/configs/ppc6xx_defconfig
index ef09f3cce1fa85..34c3859040f9f7 100644
--- a/arch/powerpc/configs/ppc6xx_defconfig
+++ b/arch/powerpc/configs/ppc6xx_defconfig
@@ -1072,7 +1072,6 @@ CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_KOI8_R=m
 CONFIG_NLS_KOI8_U=m
 CONFIG_DEBUG_INFO=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_HEADERS_INSTALL=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
diff --git a/arch/s390/configs/debug_defconfig b/arch/s390/configs/debug_defconfig
index c4f6ff98a612cd..58e54d17e3154b 100644
--- a/arch/s390/configs/debug_defconfig
+++ b/arch/s390/configs/debug_defconfig
@@ -71,7 +71,6 @@ CONFIG_MODULE_FORCE_UNLOAD=y
 CONFIG_MODVERSIONS=y
 CONFIG_MODULE_SRCVERSION_ALL=y
 CONFIG_MODULE_SIG_SHA256=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_BLK_DEV_INTEGRITY=y
 CONFIG_BLK_DEV_THROTTLING=y
 CONFIG_BLK_WBT=y
diff --git a/arch/s390/configs/defconfig b/arch/s390/configs/defconfig
index 51135893cffe34..b5e62c0d3e23e0 100644
--- a/arch/s390/configs/defconfig
+++ b/arch/s390/configs/defconfig
@@ -66,7 +66,6 @@ CONFIG_MODULE_FORCE_UNLOAD=y
 CONFIG_MODVERSIONS=y
 CONFIG_MODULE_SRCVERSION_ALL=y
 CONFIG_MODULE_SIG_SHA256=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_BLK_DEV_THROTTLING=y
 CONFIG_BLK_WBT=y
 CONFIG_BLK_CGROUP_IOLATENCY=y
diff --git a/arch/sh/configs/edosk7760_defconfig b/arch/sh/configs/edosk7760_defconfig
index 02ba622985769d..d77f54e906fd04 100644
--- a/arch/sh/configs/edosk7760_defconfig
+++ b/arch/sh/configs/edosk7760_defconfig
@@ -102,7 +102,6 @@ CONFIG_NLS_UTF8=y
 CONFIG_PRINTK_TIME=y
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_MAGIC_SYSRQ=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DEBUG_SHIRQ=y
 CONFIG_DETECT_HUNG_TASK=y
diff --git a/arch/sh/configs/sdk7780_defconfig b/arch/sh/configs/sdk7780_defconfig
index d00376eb044f8a..6c719ab4332ac9 100644
--- a/arch/sh/configs/sdk7780_defconfig
+++ b/arch/sh/configs/sdk7780_defconfig
@@ -128,7 +128,6 @@ CONFIG_NLS_ISO8859_15=y
 CONFIG_NLS_UTF8=y
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_MAGIC_SYSRQ=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DETECT_HUNG_TASK=y
 # CONFIG_SCHED_DEBUG is not set
diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig
index 78210793d357cf..9c9c4a888b1dbf 100644
--- a/arch/x86/configs/i386_defconfig
+++ b/arch/x86/configs/i386_defconfig
@@ -50,7 +50,6 @@ CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
-# CONFIG_UNUSED_SYMBOLS is not set
 CONFIG_BINFMT_MISC=y
 CONFIG_NET=y
 CONFIG_PACKET=y
diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig
index 9936528e19393a..b60bd2d8603499 100644
--- a/arch/x86/configs/x86_64_defconfig
+++ b/arch/x86/configs/x86_64_defconfig
@@ -48,7 +48,6 @@ CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
-# CONFIG_UNUSED_SYMBOLS is not set
 CONFIG_BINFMT_MISC=y
 CONFIG_NET=y
 CONFIG_PACKET=y
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 0d210d0e83e241..b9c577a3cacca6 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -61,8 +61,8 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
 	"__(start|end)_pci_.*|"
 	"__(start|end)_builtin_fw|"
-	"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl)|"
-	"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl)|"
+	"__(start|stop)___ksymtab(|_gpl)|"
+	"__(start|stop)___kcrctab(|_gpl)|"
 	"__(start|stop)___param|"
 	"__(start|stop)___modver|"
 	"__(start|stop)___bug_table|"
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 83243506e68b00..1fa338ac6a5477 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -481,20 +481,6 @@
 		__stop___ksymtab_gpl = .;				\
 	}								\
 									\
-	/* Kernel symbol table: Normal unused symbols */		\
-	__ksymtab_unused  : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) {	\
-		__start___ksymtab_unused = .;				\
-		KEEP(*(SORT(___ksymtab_unused+*)))			\
-		__stop___ksymtab_unused = .;				\
-	}								\
-									\
-	/* Kernel symbol table: GPL-only unused symbols */		\
-	__ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \
-		__start___ksymtab_unused_gpl = .;			\
-		KEEP(*(SORT(___ksymtab_unused_gpl+*)))			\
-		__stop___ksymtab_unused_gpl = .;			\
-	}								\
-									\
 	/* Kernel symbol table: Normal symbols */			\
 	__kcrctab         : AT(ADDR(__kcrctab) - LOAD_OFFSET) {		\
 		__start___kcrctab = .;					\
@@ -509,20 +495,6 @@
 		__stop___kcrctab_gpl = .;				\
 	}								\
 									\
-	/* Kernel symbol table: Normal unused symbols */		\
-	__kcrctab_unused  : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) {	\
-		__start___kcrctab_unused = .;				\
-		KEEP(*(SORT(___kcrctab_unused+*)))			\
-		__stop___kcrctab_unused = .;				\
-	}								\
-									\
-	/* Kernel symbol table: GPL-only unused symbols */		\
-	__kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \
-		__start___kcrctab_unused_gpl = .;			\
-		KEEP(*(SORT(___kcrctab_unused_gpl+*)))			\
-		__stop___kcrctab_unused_gpl = .;			\
-	}								\
-									\
 	/* Kernel symbol table: strings */				\
         __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
 		*(__ksymtab_strings)					\
diff --git a/include/linux/export.h b/include/linux/export.h
index 362b64f8d4a7c2..6271a5d9c988fa 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -160,14 +160,6 @@ struct kernel_symbol {
 #define EXPORT_SYMBOL_NS(sym, ns)	__EXPORT_SYMBOL(sym, "", #ns)
 #define EXPORT_SYMBOL_NS_GPL(sym, ns)	__EXPORT_SYMBOL(sym, "_gpl", #ns)
 
-#ifdef CONFIG_UNUSED_SYMBOLS
-#define EXPORT_UNUSED_SYMBOL(sym)	_EXPORT_SYMBOL(sym, "_unused")
-#define EXPORT_UNUSED_SYMBOL_GPL(sym)	_EXPORT_SYMBOL(sym, "_unused_gpl")
-#else
-#define EXPORT_UNUSED_SYMBOL(sym)
-#define EXPORT_UNUSED_SYMBOL_GPL(sym)
-#endif
-
 #endif /* !__ASSEMBLY__ */
 
 #endif /* _LINUX_EXPORT_H */
diff --git a/include/linux/module.h b/include/linux/module.h
index e6e50ee3041238..59f094fa6f7441 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -392,18 +392,6 @@ struct module {
 	const s32 *gpl_crcs;
 	bool using_gplonly_symbols;
 
-#ifdef CONFIG_UNUSED_SYMBOLS
-	/* unused exported symbols. */
-	const struct kernel_symbol *unused_syms;
-	const s32 *unused_crcs;
-	unsigned int num_unused_syms;
-
-	/* GPL-only, unused exported symbols. */
-	unsigned int num_unused_gpl_syms;
-	const struct kernel_symbol *unused_gpl_syms;
-	const s32 *unused_gpl_crcs;
-#endif
-
 #ifdef CONFIG_MODULE_SIG
 	/* Signature was verified. */
 	bool sig_ok;
diff --git a/init/Kconfig b/init/Kconfig
index b77c60f8b963d4..11b803b45c1995 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2262,25 +2262,8 @@ config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
 
 	  If unsure, say N.
 
-config UNUSED_SYMBOLS
-	bool "Enable unused/obsolete exported symbols"
-	default y if X86
-	help
-	  Unused but exported symbols make the kernel needlessly bigger.  For
-	  that reason most of these unused exports will soon be removed.  This
-	  option is provided temporarily to provide a transition period in case
-	  some external kernel module needs one of these symbols anyway. If you
-	  encounter such a case in your module, consider if you are actually
-	  using the right API.  (rationale: since nobody in the kernel is using
-	  this in a module, there is a pretty good chance it's actually the
-	  wrong interface to use).  If you really need the symbol, please send a
-	  mail to the linux kernel mailing list mentioning the symbol and why
-	  you really need it, and what the merge plan to the mainline kernel for
-	  your module is.
-
 config TRIM_UNUSED_KSYMS
 	bool "Trim unused exported kernel symbols"
-	depends on !UNUSED_SYMBOLS
 	help
 	  The kernel and some modules make many symbols available for
 	  other modules to use via EXPORT_SYMBOL() and variants. Depending
diff --git a/kernel/module.c b/kernel/module.c
index 492b6fa5a662c8..f8b831edb69b12 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -415,14 +415,6 @@ extern const struct kernel_symbol __start___ksymtab_gpl[];
 extern const struct kernel_symbol __stop___ksymtab_gpl[];
 extern const s32 __start___kcrctab[];
 extern const s32 __start___kcrctab_gpl[];
-#ifdef CONFIG_UNUSED_SYMBOLS
-extern const struct kernel_symbol __start___ksymtab_unused[];
-extern const struct kernel_symbol __stop___ksymtab_unused[];
-extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
-extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
-extern const s32 __start___kcrctab_unused[];
-extern const s32 __start___kcrctab_unused_gpl[];
-#endif
 
 #ifndef CONFIG_MODVERSIONS
 #define symversion(base, idx) NULL
@@ -437,7 +429,6 @@ struct symsearch {
 		NOT_GPL_ONLY,
 		GPL_ONLY,
 	} license;
-	bool unused;
 };
 
 struct find_symbol_arg {
@@ -461,19 +452,6 @@ static bool check_exported_symbol(const struct symsearch *syms,
 
 	if (!fsa->gplok && syms->license == GPL_ONLY)
 		return false;
-
-#ifdef CONFIG_UNUSED_SYMBOLS
-	if (syms->unused && fsa->warn) {
-		pr_warn("Symbol %s is marked as UNUSED, however this module is "
-			"using it.\n", fsa->name);
-		pr_warn("This symbol will go away in the future.\n");
-		pr_warn("Please evaluate if this is the right api to use and "
-			"if it really is, submit a report to the linux kernel "
-			"mailing list together with submitting your code for "
-			"inclusion.\n");
-	}
-#endif
-
 	fsa->owner = owner;
 	fsa->crc = symversion(syms->crcs, symnum);
 	fsa->sym = &syms->start[symnum];
@@ -540,18 +518,10 @@ static bool find_symbol(struct find_symbol_arg *fsa)
 {
 	static const struct symsearch arr[] = {
 		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
-		  NOT_GPL_ONLY, false },
+		  NOT_GPL_ONLY },
 		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
 		  __start___kcrctab_gpl,
-		  GPL_ONLY, false },
-#ifdef CONFIG_UNUSED_SYMBOLS
-		{ __start___ksymtab_unused, __stop___ksymtab_unused,
-		  __start___kcrctab_unused,
-		  NOT_GPL_ONLY, true },
-		{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
-		  __start___kcrctab_unused_gpl,
-		  GPL_ONLY, true },
-#endif
+		  GPL_ONLY },
 	};
 	struct module *mod;
 	unsigned int i;
@@ -566,20 +536,10 @@ static bool find_symbol(struct find_symbol_arg *fsa)
 				lockdep_is_held(&module_mutex)) {
 		struct symsearch arr[] = {
 			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
-			  NOT_GPL_ONLY, false },
+			  NOT_GPL_ONLY },
 			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
 			  mod->gpl_crcs,
-			  GPL_ONLY, false },
-#ifdef CONFIG_UNUSED_SYMBOLS
-			{ mod->unused_syms,
-			  mod->unused_syms + mod->num_unused_syms,
-			  mod->unused_crcs,
-			  NOT_GPL_ONLY, true },
-			{ mod->unused_gpl_syms,
-			  mod->unused_gpl_syms + mod->num_unused_gpl_syms,
-			  mod->unused_gpl_crcs,
-			  GPL_ONLY, true },
-#endif
+			  GPL_ONLY },
 		};
 
 		if (mod->state == MODULE_STATE_UNFORMED)
@@ -2279,10 +2239,6 @@ static int verify_exported_symbols(struct module *mod)
 	} arr[] = {
 		{ mod->syms, mod->num_syms },
 		{ mod->gpl_syms, mod->num_gpl_syms },
-#ifdef CONFIG_UNUSED_SYMBOLS
-		{ mod->unused_syms, mod->num_unused_syms },
-		{ mod->unused_gpl_syms, mod->num_unused_gpl_syms },
-#endif
 	};
 
 	for (i = 0; i < ARRAY_SIZE(arr); i++) {
@@ -3197,16 +3153,6 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 				     &mod->num_gpl_syms);
 	mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
 
-#ifdef CONFIG_UNUSED_SYMBOLS
-	mod->unused_syms = section_objs(info, "__ksymtab_unused",
-					sizeof(*mod->unused_syms),
-					&mod->num_unused_syms);
-	mod->unused_crcs = section_addr(info, "__kcrctab_unused");
-	mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl",
-					    sizeof(*mod->unused_gpl_syms),
-					    &mod->num_unused_gpl_syms);
-	mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl");
-#endif
 #ifdef CONFIG_CONSTRUCTORS
 	mod->ctors = section_objs(info, ".ctors",
 				  sizeof(*mod->ctors), &mod->num_ctors);
@@ -3387,13 +3333,8 @@ static int check_module_license_and_versions(struct module *mod)
 		pr_warn("%s: module license taints kernel.\n", mod->name);
 
 #ifdef CONFIG_MODVERSIONS
-	if ((mod->num_syms && !mod->crcs)
-	    || (mod->num_gpl_syms && !mod->gpl_crcs)
-#ifdef CONFIG_UNUSED_SYMBOLS
-	    || (mod->num_unused_syms && !mod->unused_crcs)
-	    || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
-#endif
-		) {
+	if ((mod->num_syms && !mod->crcs) ||
+	    (mod->num_gpl_syms && !mod->gpl_crcs)) {
 		return try_to_force_load(mod,
 					 "no versions for exported symbols");
 	}
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 92e888ed939f98..eabd2d5467b156 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4290,8 +4290,7 @@ sub process {
 		if (defined $realline_next &&
 		    exists $lines[$realline_next - 1] &&
 		    !defined $suppress_export{$realline_next} &&
-		    ($lines[$realline_next - 1] =~ /EXPORT_SYMBOL.*\((.*)\)/ ||
-		     $lines[$realline_next - 1] =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
+		    ($lines[$realline_next - 1] =~ /EXPORT_SYMBOL.*\((.*)\)/)) {
 			# Handle definitions which produce identifiers with
 			# a prefix:
 			#   XXX(foo);
@@ -4318,8 +4317,7 @@ sub process {
 		}
 		if (!defined $suppress_export{$linenr} &&
 		    $prevline =~ /^.\s*$/ &&
-		    ($line =~ /EXPORT_SYMBOL.*\((.*)\)/ ||
-		     $line =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
+		    ($line =~ /EXPORT_SYMBOL.*\((.*)\)/)) {
 #print "FOO B <$lines[$linenr - 1]>\n";
 			$suppress_export{$linenr} = 2;
 		}
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 25c1446055d16b..20fc57837881ab 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -43,8 +43,9 @@ static int allow_missing_ns_imports;
 static bool error_occurred;
 
 enum export {
-	export_plain,      export_unused,     export_gpl,
-	export_unused_gpl, export_unknown
+	export_plain,
+	export_gpl,
+	export_unknown
 };
 
 /* In kernel, this size is defined in linux/module.h;
@@ -301,9 +302,7 @@ static const struct {
 	enum export export;
 } export_list[] = {
 	{ .str = "EXPORT_SYMBOL",            .export = export_plain },
-	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
-	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
 	{ .str = "(unknown)",                .export = export_unknown },
 };
 
@@ -362,12 +361,8 @@ static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
 
 	if (strstarts(secname, "___ksymtab+"))
 		return export_plain;
-	else if (strstarts(secname, "___ksymtab_unused+"))
-		return export_unused;
 	else if (strstarts(secname, "___ksymtab_gpl+"))
 		return export_gpl;
-	else if (strstarts(secname, "___ksymtab_unused_gpl+"))
-		return export_unused_gpl;
 	else
 		return export_unknown;
 }
@@ -376,12 +371,8 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 {
 	if (sec == elf->export_sec)
 		return export_plain;
-	else if (sec == elf->export_unused_sec)
-		return export_unused;
 	else if (sec == elf->export_gpl_sec)
 		return export_gpl;
-	else if (sec == elf->export_unused_gpl_sec)
-		return export_unused_gpl;
 	else
 		return export_unknown;
 }
@@ -585,12 +576,8 @@ static int parse_elf(struct elf_info *info, const char *filename)
 			info->modinfo_len = sechdrs[i].sh_size;
 		} else if (strcmp(secname, "__ksymtab") == 0)
 			info->export_sec = i;
-		else if (strcmp(secname, "__ksymtab_unused") == 0)
-			info->export_unused_sec = i;
 		else if (strcmp(secname, "__ksymtab_gpl") == 0)
 			info->export_gpl_sec = i;
-		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
-			info->export_unused_gpl_sec = i;
 
 		if (sechdrs[i].sh_type == SHT_SYMTAB) {
 			unsigned int sh_link_idx;
@@ -2141,32 +2128,13 @@ static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
 		error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
 		      m, s);
 		break;
-	case export_unused_gpl:
-		error("GPL-incompatible module %s.ko uses GPL-only symbol marked UNUSED '%s'\n",
-		      m, s);
-		break;
 	case export_plain:
-	case export_unused:
 	case export_unknown:
 		/* ignore */
 		break;
 	}
 }
 
-static void check_for_unused(enum export exp, const char *m, const char *s)
-{
-	switch (exp) {
-	case export_unused:
-	case export_unused_gpl:
-		warn("module %s.ko uses symbol '%s' marked UNUSED\n",
-		     m, s);
-		break;
-	default:
-		/* ignore */
-		break;
-	}
-}
-
 static void check_exports(struct module *mod)
 {
 	struct symbol *s, *exp;
@@ -2197,7 +2165,6 @@ static void check_exports(struct module *mod)
 
 		if (!mod->gpl_compatible)
 			check_for_gpl_usage(exp->export, basename, exp->name);
-		check_for_unused(exp->export, basename, exp->name);
 	}
 }
 
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 834220de002bd1..0c47ff95c0e227 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -139,9 +139,7 @@ struct elf_info {
 	Elf_Sym      *symtab_start;
 	Elf_Sym      *symtab_stop;
 	Elf_Section  export_sec;
-	Elf_Section  export_unused_sec;
 	Elf_Section  export_gpl_sec;
-	Elf_Section  export_unused_gpl_sec;
 	char         *strtab;
 	char	     *modinfo;
 	unsigned int modinfo_len;
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index d82b452e8a7168..24e8af579ce378 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -11,12 +11,8 @@ SECTIONS {
 
 	__ksymtab		0 : { *(SORT(___ksymtab+*)) }
 	__ksymtab_gpl		0 : { *(SORT(___ksymtab_gpl+*)) }
-	__ksymtab_unused	0 : { *(SORT(___ksymtab_unused+*)) }
-	__ksymtab_unused_gpl	0 : { *(SORT(___ksymtab_unused_gpl+*)) }
 	__kcrctab		0 : { *(SORT(___kcrctab+*)) }
 	__kcrctab_gpl		0 : { *(SORT(___kcrctab_gpl+*)) }
-	__kcrctab_unused	0 : { *(SORT(___kcrctab_unused+*)) }
-	__kcrctab_unused_gpl	0 : { *(SORT(___kcrctab_unused_gpl+*)) }
 
 	.init_array		0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }
 
diff --git a/tools/include/linux/export.h b/tools/include/linux/export.h
index 9f61349a8944e1..acb6f4daa2f0b4 100644
--- a/tools/include/linux/export.h
+++ b/tools/include/linux/export.h
@@ -3,7 +3,5 @@
 
 #define EXPORT_SYMBOL(sym)
 #define EXPORT_SYMBOL_GPL(sym)
-#define EXPORT_UNUSED_SYMBOL(sym)
-#define EXPORT_UNUSED_SYMBOL_GPL(sym)
 
 #endif
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
  2021-01-28 18:14   ` Christoph Hellwig
  (?)
@ 2021-01-28 20:50     ` Thiago Jung Bauermann
  -1 siblings, 0 replies; 69+ messages in thread
From: Thiago Jung Bauermann @ 2021-01-28 20:50 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence, Michal Marek, linux-kbuild,
	Masahiro Yamada, linux-kernel, dri-devel, live-patching,
	linuxppc-dev


Hi Christoph,

Christoph Hellwig <hch@lst.de> writes:

> diff --git a/kernel/module.c b/kernel/module.c
> index 981302f616b411..6772fb2680eb3e 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -668,7 +668,6 @@ static struct module *find_module_all(const char *name, size_t len,
>  
>  struct module *find_module(const char *name)
>  {
> -	module_assert_mutex();

Does it make sense to replace the assert above with the warn below (untested)?

     RCU_LOCKDEP_WARN(rcu_read_lock_sched_held());

>  	return find_module_all(name, strlen(name), false);
>  }

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-01-28 20:50     ` Thiago Jung Bauermann
  0 siblings, 0 replies; 69+ messages in thread
From: Thiago Jung Bauermann @ 2021-01-28 20:50 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, Miroslav Benes, linuxppc-dev


Hi Christoph,

Christoph Hellwig <hch@lst.de> writes:

> diff --git a/kernel/module.c b/kernel/module.c
> index 981302f616b411..6772fb2680eb3e 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -668,7 +668,6 @@ static struct module *find_module_all(const char *name, size_t len,
>  
>  struct module *find_module(const char *name)
>  {
> -	module_assert_mutex();

Does it make sense to replace the assert above with the warn below (untested)?

     RCU_LOCKDEP_WARN(rcu_read_lock_sched_held());

>  	return find_module_all(name, strlen(name), false);
>  }

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-01-28 20:50     ` Thiago Jung Bauermann
  0 siblings, 0 replies; 69+ messages in thread
From: Thiago Jung Bauermann @ 2021-01-28 20:50 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, linux-kernel,
	live-patching, Michal Marek, Joe Lawrence, dri-devel,
	Thomas Zimmermann, Jessica Yu, Frederic Barrat, Miroslav Benes,
	linuxppc-dev


Hi Christoph,

Christoph Hellwig <hch@lst.de> writes:

> diff --git a/kernel/module.c b/kernel/module.c
> index 981302f616b411..6772fb2680eb3e 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -668,7 +668,6 @@ static struct module *find_module_all(const char *name, size_t len,
>  
>  struct module *find_module(const char *name)
>  {
> -	module_assert_mutex();

Does it make sense to replace the assert above with the warn below (untested)?

     RCU_LOCKDEP_WARN(rcu_read_lock_sched_held());

>  	return find_module_all(name, strlen(name), false);
>  }

-- 
Thiago Jung Bauermann
IBM Linux Technology Center
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
  2021-01-28 20:50     ` Thiago Jung Bauermann
@ 2021-01-29  5:10       ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-29  5:10 UTC (permalink / raw)
  To: Thiago Jung Bauermann
  Cc: Christoph Hellwig, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Jessica Yu, Josh Poimboeuf,
	Jiri Kosina, Miroslav Benes, Petr Mladek, Joe Lawrence,
	Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

On Thu, Jan 28, 2021 at 05:50:56PM -0300, Thiago Jung Bauermann wrote:
> >  struct module *find_module(const char *name)
> >  {
> > -	module_assert_mutex();
> 
> Does it make sense to replace the assert above with the warn below (untested)?
> 
>      RCU_LOCKDEP_WARN(rcu_read_lock_sched_held());

One caller actually holds module_mutex still.  And find_module_all,
which implements the actual logic already asserts that either
module_mutex is held or rcu_read_lock, so I don't tink we need an
extra one here.

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-01-29  5:10       ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-29  5:10 UTC (permalink / raw)
  To: Thiago Jung Bauermann
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, Miroslav Benes, linuxppc-dev,
	Christoph Hellwig

On Thu, Jan 28, 2021 at 05:50:56PM -0300, Thiago Jung Bauermann wrote:
> >  struct module *find_module(const char *name)
> >  {
> > -	module_assert_mutex();
> 
> Does it make sense to replace the assert above with the warn below (untested)?
> 
>      RCU_LOCKDEP_WARN(rcu_read_lock_sched_held());

One caller actually holds module_mutex still.  And find_module_all,
which implements the actual logic already asserts that either
module_mutex is held or rcu_read_lock, so I don't tink we need an
extra one here.

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
  2021-01-28 18:14 ` [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol Christoph Hellwig
@ 2021-01-29  9:43   ` Petr Mladek
  2021-02-01 11:47       ` Christoph Hellwig
  2021-02-01 14:02     ` Miroslav Benes
  1 sibling, 1 reply; 69+ messages in thread
From: Petr Mladek @ 2021-01-29  9:43 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jiri Kosina, Andrew Donnellan, linux-kbuild, David Airlie,
	Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst, linux-kernel,
	Maxime Ripard, live-patching, Michal Marek, Joe Lawrence,
	dri-devel, Thomas Zimmermann, Jessica Yu, Frederic Barrat,
	Daniel Vetter, Miroslav Benes, linuxppc-dev

On Thu 2021-01-28 19:14:13, Christoph Hellwig wrote:
> Require an explicit call to module_kallsyms_on_each_symbol to look
> for symbols in modules instead of the call from kallsyms_on_each_symbol,
> and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
> of leaving that up to the caller.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  kernel/kallsyms.c       | 6 +++++-
>  kernel/livepatch/core.c | 6 +-----
>  kernel/module.c         | 8 ++++----
>  3 files changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
> index fe9de067771c34..a0d3f0865916f9 100644
> --- a/kernel/kallsyms.c
> +++ b/kernel/kallsyms.c
> @@ -177,6 +177,10 @@ unsigned long kallsyms_lookup_name(const char *name)
>  	return module_kallsyms_lookup_name(name);
>  }
>  
> +/*
> + * Iterate over all symbols in vmlinux.  For symbols from modules use
> + * module_kallsyms_on_each_symbol instead.
> + */
>  int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
>  				      unsigned long),
>  			    void *data)
> @@ -192,7 +196,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
>  		if (ret != 0)
>  			return ret;
>  	}
> -	return module_kallsyms_on_each_symbol(fn, data);
> +	return 0;
>  }
>  
>  static unsigned long get_symbol_pos(unsigned long addr,
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index 262cd9b003b9f0..f591dac5e86ef4 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -164,12 +164,8 @@ static int klp_find_object_symbol(const char *objname, const char *name,
>  		.pos = sympos,
>  	};
>  
> -	mutex_lock(&module_mutex);
> -	if (objname)
> +	if (objname || !kallsyms_on_each_symbol(klp_find_callback, &args))
>  		module_kallsyms_on_each_symbol(klp_find_callback, &args);
> -	else
> -		kallsyms_on_each_symbol(klp_find_callback, &args);
> -	mutex_unlock(&module_mutex);

This change is not needed. (objname == NULL) means that we are
interested only in symbols in "vmlinux".

module_kallsyms_on_each_symbol(klp_find_callback, &args)
will always fail when objname == NULL.

Best Regards,
Petr

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
  2021-01-28 18:14   ` Christoph Hellwig
@ 2021-01-29 10:04     ` Petr Mladek
  -1 siblings, 0 replies; 69+ messages in thread
From: Petr Mladek @ 2021-01-29 10:04 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Joe Lawrence, Masahiro Yamada, Michal Marek, linux-kernel,
	linuxppc-dev, dri-devel, live-patching, linux-kbuild

On Thu 2021-01-28 19:14:12, Christoph Hellwig wrote:
> Allow for a RCU-sched critical section around find_module, following
> the lower level find_module_all helper, and switch the two callers
> outside of module.c to use such a RCU-sched critical section instead
> of module_mutex.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

It looks good and safe.

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-01-29 10:04     ` Petr Mladek
  0 siblings, 0 replies; 69+ messages in thread
From: Petr Mladek @ 2021-01-29 10:04 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jiri Kosina, Andrew Donnellan, linux-kbuild, David Airlie,
	Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst, linux-kernel,
	Maxime Ripard, live-patching, Michal Marek, Joe Lawrence,
	dri-devel, Thomas Zimmermann, Jessica Yu, Frederic Barrat,
	Daniel Vetter, Miroslav Benes, linuxppc-dev

On Thu 2021-01-28 19:14:12, Christoph Hellwig wrote:
> Allow for a RCU-sched critical section around find_module, following
> the lower level find_module_all helper, and switch the two callers
> outside of module.c to use such a RCU-sched critical section instead
> of module_mutex.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

It looks good and safe.

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 03/13] module: unexport find_module and module_mutex
  2021-01-28 18:14   ` Christoph Hellwig
  (?)
@ 2021-01-29 15:16   ` Miroslav Benes
  -1 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-01-29 15:16 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, linuxppc-dev

On Thu, 28 Jan 2021, Christoph Hellwig wrote:

> find_module is not used by modular code any more, and random driver code
> has no business calling it to start with.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Miroslav Benes <mbenes@suse.cz>

M

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
  2021-01-28 18:14   ` Christoph Hellwig
                     ` (2 preceding siblings ...)
  (?)
@ 2021-01-29 15:29   ` Miroslav Benes
  2021-02-01 11:46       ` Christoph Hellwig
  2021-02-01 12:10       ` Jessica Yu
  -1 siblings, 2 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-01-29 15:29 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, linuxppc-dev

On Thu, 28 Jan 2021, Christoph Hellwig wrote:

> Allow for a RCU-sched critical section around find_module, following
> the lower level find_module_all helper, and switch the two callers
> outside of module.c to use such a RCU-sched critical section instead
> of module_mutex.

That's a nice idea.
 
> @@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object *obj)
>  	if (!klp_is_module(obj))
>  		return;
>  
> -	mutex_lock(&module_mutex);
> +	rcu_read_lock_sched();
>  	/*
>  	 * We do not want to block removal of patched modules and therefore
>  	 * we do not take a reference here. The patches are removed by
> @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj)
>  	if (mod && mod->klp_alive)

RCU always baffles me a bit, so I'll ask. Don't we need 
rcu_dereference_sched() here? "mod" comes from a RCU-protected list, so I 
wonder.

>  		obj->mod = mod;
>  
> -	mutex_unlock(&module_mutex);
> +	rcu_read_unlock_sched();
>  }

Thanks

Miroslav

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
  2021-01-29  5:10       ` Christoph Hellwig
@ 2021-01-29 21:29         ` Thiago Jung Bauermann
  -1 siblings, 0 replies; 69+ messages in thread
From: Thiago Jung Bauermann @ 2021-01-29 21:29 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence, Michal Marek, linux-kbuild,
	Masahiro Yamada, linux-kernel, dri-devel, live-patching,
	linuxppc-dev


Christoph Hellwig <hch@lst.de> writes:

> On Thu, Jan 28, 2021 at 05:50:56PM -0300, Thiago Jung Bauermann wrote:
>> >  struct module *find_module(const char *name)
>> >  {
>> > -	module_assert_mutex();
>> 
>> Does it make sense to replace the assert above with the warn below (untested)?
>> 
>>      RCU_LOCKDEP_WARN(rcu_read_lock_sched_held());
>
> One caller actually holds module_mutex still.  And find_module_all,
> which implements the actual logic already asserts that either
> module_mutex is held or rcu_read_lock, so I don't tink we need an
> extra one here.

Ok, thanks for the clarification.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-01-29 21:29         ` Thiago Jung Bauermann
  0 siblings, 0 replies; 69+ messages in thread
From: Thiago Jung Bauermann @ 2021-01-29 21:29 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, Miroslav Benes, linuxppc-dev


Christoph Hellwig <hch@lst.de> writes:

> On Thu, Jan 28, 2021 at 05:50:56PM -0300, Thiago Jung Bauermann wrote:
>> >  struct module *find_module(const char *name)
>> >  {
>> > -	module_assert_mutex();
>> 
>> Does it make sense to replace the assert above with the warn below (untested)?
>> 
>>      RCU_LOCKDEP_WARN(rcu_read_lock_sched_held());
>
> One caller actually holds module_mutex still.  And find_module_all,
> which implements the actual logic already asserts that either
> module_mutex is held or rcu_read_lock, so I don't tink we need an
> extra one here.

Ok, thanks for the clarification.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
  2021-01-29 15:29   ` Miroslav Benes
@ 2021-02-01 11:46       ` Christoph Hellwig
  2021-02-01 12:10       ` Jessica Yu
  1 sibling, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-02-01 11:46 UTC (permalink / raw)
  To: Miroslav Benes
  Cc: Christoph Hellwig, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Jessica Yu, Josh Poimboeuf,
	Jiri Kosina, Petr Mladek, Joe Lawrence, Masahiro Yamada,
	Michal Marek, linux-kernel, linuxppc-dev, dri-devel,
	live-patching, linux-kbuild

On Fri, Jan 29, 2021 at 04:29:02PM +0100, Miroslav Benes wrote:
> >  
> > -	mutex_lock(&module_mutex);
> > +	rcu_read_lock_sched();
> >  	/*
> >  	 * We do not want to block removal of patched modules and therefore
> >  	 * we do not take a reference here. The patches are removed by
> > @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj)
> >  	if (mod && mod->klp_alive)
> 
> RCU always baffles me a bit, so I'll ask. Don't we need 
> rcu_dereference_sched() here? "mod" comes from a RCU-protected list, so I 
> wonder.

rcu_dereference* is only used for dereferencing points where that
reference itself is RCU protected, that is the lookup of mod itself down
in find_module_all in this case.

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-02-01 11:46       ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-02-01 11:46 UTC (permalink / raw)
  To: Miroslav Benes
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, linuxppc-dev, Christoph Hellwig

On Fri, Jan 29, 2021 at 04:29:02PM +0100, Miroslav Benes wrote:
> >  
> > -	mutex_lock(&module_mutex);
> > +	rcu_read_lock_sched();
> >  	/*
> >  	 * We do not want to block removal of patched modules and therefore
> >  	 * we do not take a reference here. The patches are removed by
> > @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj)
> >  	if (mod && mod->klp_alive)
> 
> RCU always baffles me a bit, so I'll ask. Don't we need 
> rcu_dereference_sched() here? "mod" comes from a RCU-protected list, so I 
> wonder.

rcu_dereference* is only used for dereferencing points where that
reference itself is RCU protected, that is the lookup of mod itself down
in find_module_all in this case.

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
  2021-01-29  9:43   ` Petr Mladek
@ 2021-02-01 11:47       ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-02-01 11:47 UTC (permalink / raw)
  To: Petr Mladek
  Cc: Christoph Hellwig, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Jessica Yu, Josh Poimboeuf,
	Jiri Kosina, Miroslav Benes, Joe Lawrence, Masahiro Yamada,
	Michal Marek, linux-kernel, linuxppc-dev, dri-devel,
	live-patching, linux-kbuild

On Fri, Jan 29, 2021 at 10:43:36AM +0100, Petr Mladek wrote:
> > --- a/kernel/livepatch/core.c
> > +++ b/kernel/livepatch/core.c
> > @@ -164,12 +164,8 @@ static int klp_find_object_symbol(const char *objname, const char *name,
> >  		.pos = sympos,
> >  	};
> >  
> > -	mutex_lock(&module_mutex);
> > -	if (objname)
> > +	if (objname || !kallsyms_on_each_symbol(klp_find_callback, &args))
> >  		module_kallsyms_on_each_symbol(klp_find_callback, &args);
> > -	else
> > -		kallsyms_on_each_symbol(klp_find_callback, &args);
> > -	mutex_unlock(&module_mutex);
> 
> This change is not needed. (objname == NULL) means that we are
> interested only in symbols in "vmlinux".
> 
> module_kallsyms_on_each_symbol(klp_find_callback, &args)
> will always fail when objname == NULL.

I just tried to keep the old behavior.  I can respin it with your
recommended change noting the change in behavior, though.

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
@ 2021-02-01 11:47       ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-02-01 11:47 UTC (permalink / raw)
  To: Petr Mladek
  Cc: Jiri Kosina, Andrew Donnellan, linux-kbuild, David Airlie,
	Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst, linux-kernel,
	Maxime Ripard, live-patching, Michal Marek, Joe Lawrence,
	dri-devel, Thomas Zimmermann, Jessica Yu, Frederic Barrat,
	Daniel Vetter, Miroslav Benes, linuxppc-dev, Christoph Hellwig

On Fri, Jan 29, 2021 at 10:43:36AM +0100, Petr Mladek wrote:
> > --- a/kernel/livepatch/core.c
> > +++ b/kernel/livepatch/core.c
> > @@ -164,12 +164,8 @@ static int klp_find_object_symbol(const char *objname, const char *name,
> >  		.pos = sympos,
> >  	};
> >  
> > -	mutex_lock(&module_mutex);
> > -	if (objname)
> > +	if (objname || !kallsyms_on_each_symbol(klp_find_callback, &args))
> >  		module_kallsyms_on_each_symbol(klp_find_callback, &args);
> > -	else
> > -		kallsyms_on_each_symbol(klp_find_callback, &args);
> > -	mutex_unlock(&module_mutex);
> 
> This change is not needed. (objname == NULL) means that we are
> interested only in symbols in "vmlinux".
> 
> module_kallsyms_on_each_symbol(klp_find_callback, &args)
> will always fail when objname == NULL.

I just tried to keep the old behavior.  I can respin it with your
recommended change noting the change in behavior, though.

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
  2021-01-29 15:29   ` Miroslav Benes
  2021-02-01 11:46       ` Christoph Hellwig
@ 2021-02-01 12:10       ` Jessica Yu
  1 sibling, 0 replies; 69+ messages in thread
From: Jessica Yu @ 2021-02-01 12:10 UTC (permalink / raw)
  To: Miroslav Benes
  Cc: Christoph Hellwig, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Josh Poimboeuf, Jiri Kosina,
	Petr Mladek, Joe Lawrence, Masahiro Yamada, Michal Marek,
	linux-kernel, linuxppc-dev, dri-devel, live-patching,
	linux-kbuild

+++ Miroslav Benes [29/01/21 16:29 +0100]:
>On Thu, 28 Jan 2021, Christoph Hellwig wrote:
>
>> Allow for a RCU-sched critical section around find_module, following
>> the lower level find_module_all helper, and switch the two callers
>> outside of module.c to use such a RCU-sched critical section instead
>> of module_mutex.
>
>That's a nice idea.
>
>> @@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object *obj)
>>  	if (!klp_is_module(obj))
>>  		return;
>>
>> -	mutex_lock(&module_mutex);
>> +	rcu_read_lock_sched();
>>  	/*
>>  	 * We do not want to block removal of patched modules and therefore
>>  	 * we do not take a reference here. The patches are removed by
>> @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj)
>>  	if (mod && mod->klp_alive)
>
>RCU always baffles me a bit, so I'll ask. Don't we need
>rcu_dereference_sched() here? "mod" comes from a RCU-protected list, so I
>wonder.

Same here :-) I had to double check the RCU documentation. For our
modules list case I believe the rcu list API should take care of that
for us. Worth noting is this snippet from Documentation/RCU/whatisRCU.txt:

    rcu_dereference() is typically used indirectly, via the _rcu
    list-manipulation primitives, such as list_for_each_entry_rcu()



^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-02-01 12:10       ` Jessica Yu
  0 siblings, 0 replies; 69+ messages in thread
From: Jessica Yu @ 2021-02-01 12:10 UTC (permalink / raw)
  To: Miroslav Benes
  Cc: Petr Mladek, Joe Lawrence, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Jiri Kosina, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	dri-devel, Thomas Zimmermann, Josh Poimboeuf, Frederic Barrat,
	Daniel Vetter, linuxppc-dev, Christoph Hellwig

+++ Miroslav Benes [29/01/21 16:29 +0100]:
>On Thu, 28 Jan 2021, Christoph Hellwig wrote:
>
>> Allow for a RCU-sched critical section around find_module, following
>> the lower level find_module_all helper, and switch the two callers
>> outside of module.c to use such a RCU-sched critical section instead
>> of module_mutex.
>
>That's a nice idea.
>
>> @@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object *obj)
>>  	if (!klp_is_module(obj))
>>  		return;
>>
>> -	mutex_lock(&module_mutex);
>> +	rcu_read_lock_sched();
>>  	/*
>>  	 * We do not want to block removal of patched modules and therefore
>>  	 * we do not take a reference here. The patches are removed by
>> @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj)
>>  	if (mod && mod->klp_alive)
>
>RCU always baffles me a bit, so I'll ask. Don't we need
>rcu_dereference_sched() here? "mod" comes from a RCU-protected list, so I
>wonder.

Same here :-) I had to double check the RCU documentation. For our
modules list case I believe the rcu list API should take care of that
for us. Worth noting is this snippet from Documentation/RCU/whatisRCU.txt:

    rcu_dereference() is typically used indirectly, via the _rcu
    list-manipulation primitives, such as list_for_each_entry_rcu()



^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-02-01 12:10       ` Jessica Yu
  0 siblings, 0 replies; 69+ messages in thread
From: Jessica Yu @ 2021-02-01 12:10 UTC (permalink / raw)
  To: Miroslav Benes
  Cc: Petr Mladek, Joe Lawrence, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Jiri Kosina, linux-kernel,
	live-patching, Michal Marek, dri-devel, Thomas Zimmermann,
	Josh Poimboeuf, Frederic Barrat, linuxppc-dev, Christoph Hellwig

+++ Miroslav Benes [29/01/21 16:29 +0100]:
>On Thu, 28 Jan 2021, Christoph Hellwig wrote:
>
>> Allow for a RCU-sched critical section around find_module, following
>> the lower level find_module_all helper, and switch the two callers
>> outside of module.c to use such a RCU-sched critical section instead
>> of module_mutex.
>
>That's a nice idea.
>
>> @@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object *obj)
>>  	if (!klp_is_module(obj))
>>  		return;
>>
>> -	mutex_lock(&module_mutex);
>> +	rcu_read_lock_sched();
>>  	/*
>>  	 * We do not want to block removal of patched modules and therefore
>>  	 * we do not take a reference here. The patches are removed by
>> @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj)
>>  	if (mod && mod->klp_alive)
>
>RCU always baffles me a bit, so I'll ask. Don't we need
>rcu_dereference_sched() here? "mod" comes from a RCU-protected list, so I
>wonder.

Same here :-) I had to double check the RCU documentation. For our
modules list case I believe the rcu list API should take care of that
for us. Worth noting is this snippet from Documentation/RCU/whatisRCU.txt:

    rcu_dereference() is typically used indirectly, via the _rcu
    list-manipulation primitives, such as list_for_each_entry_rcu()


_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
  2021-02-01 12:10       ` Jessica Yu
  (?)
@ 2021-02-01 13:16         ` Miroslav Benes
  -1 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-01 13:16 UTC (permalink / raw)
  To: Jessica Yu
  Cc: Christoph Hellwig, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Josh Poimboeuf, Jiri Kosina,
	Petr Mladek, Joe Lawrence, Masahiro Yamada, Michal Marek,
	linux-kernel, linuxppc-dev, dri-devel, live-patching,
	linux-kbuild

On Mon, 1 Feb 2021, Jessica Yu wrote:

> +++ Miroslav Benes [29/01/21 16:29 +0100]:
> >On Thu, 28 Jan 2021, Christoph Hellwig wrote:
> >
> >> Allow for a RCU-sched critical section around find_module, following
> >> the lower level find_module_all helper, and switch the two callers
> >> outside of module.c to use such a RCU-sched critical section instead
> >> of module_mutex.
> >
> >That's a nice idea.
> >
> >> @@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object
> >> *obj)
> >>   if (!klp_is_module(obj))
> >>    return;
> >>
> >> -	mutex_lock(&module_mutex);
> >> +	rcu_read_lock_sched();
> >>   /*
> >>    * We do not want to block removal of patched modules and therefore
> >>    * we do not take a reference here. The patches are removed by
> >> @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object
> >> *obj)
> >>   if (mod && mod->klp_alive)
> >
> >RCU always baffles me a bit, so I'll ask. Don't we need
> >rcu_dereference_sched() here? "mod" comes from a RCU-protected list, so I
> >wonder.
> 
> Same here :-) I had to double check the RCU documentation. For our
> modules list case I believe the rcu list API should take care of that
> for us. Worth noting is this snippet from Documentation/RCU/whatisRCU.txt:
> 
>    rcu_dereference() is typically used indirectly, via the _rcu
>    list-manipulation primitives, such as list_for_each_entry_rcu()

Ok, thanks to both for checking and explanation.

Ack to the patch then.

Miroslav

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-02-01 13:16         ` Miroslav Benes
  0 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-01 13:16 UTC (permalink / raw)
  To: Jessica Yu
  Cc: Petr Mladek, Joe Lawrence, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Jiri Kosina, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	dri-devel, Thomas Zimmermann, Josh Poimboeuf, Frederic Barrat,
	Daniel Vetter, linuxppc-dev, Christoph Hellwig

On Mon, 1 Feb 2021, Jessica Yu wrote:

> +++ Miroslav Benes [29/01/21 16:29 +0100]:
> >On Thu, 28 Jan 2021, Christoph Hellwig wrote:
> >
> >> Allow for a RCU-sched critical section around find_module, following
> >> the lower level find_module_all helper, and switch the two callers
> >> outside of module.c to use such a RCU-sched critical section instead
> >> of module_mutex.
> >
> >That's a nice idea.
> >
> >> @@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object
> >> *obj)
> >>   if (!klp_is_module(obj))
> >>    return;
> >>
> >> -	mutex_lock(&module_mutex);
> >> +	rcu_read_lock_sched();
> >>   /*
> >>    * We do not want to block removal of patched modules and therefore
> >>    * we do not take a reference here. The patches are removed by
> >> @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object
> >> *obj)
> >>   if (mod && mod->klp_alive)
> >
> >RCU always baffles me a bit, so I'll ask. Don't we need
> >rcu_dereference_sched() here? "mod" comes from a RCU-protected list, so I
> >wonder.
> 
> Same here :-) I had to double check the RCU documentation. For our
> modules list case I believe the rcu list API should take care of that
> for us. Worth noting is this snippet from Documentation/RCU/whatisRCU.txt:
> 
>    rcu_dereference() is typically used indirectly, via the _rcu
>    list-manipulation primitives, such as list_for_each_entry_rcu()

Ok, thanks to both for checking and explanation.

Ack to the patch then.

Miroslav

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 04/13] module: use RCU to synchronize find_module
@ 2021-02-01 13:16         ` Miroslav Benes
  0 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-01 13:16 UTC (permalink / raw)
  To: Jessica Yu
  Cc: Petr Mladek, Joe Lawrence, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Jiri Kosina, linux-kernel,
	live-patching, Michal Marek, dri-devel, Thomas Zimmermann,
	Josh Poimboeuf, Frederic Barrat, linuxppc-dev, Christoph Hellwig

On Mon, 1 Feb 2021, Jessica Yu wrote:

> +++ Miroslav Benes [29/01/21 16:29 +0100]:
> >On Thu, 28 Jan 2021, Christoph Hellwig wrote:
> >
> >> Allow for a RCU-sched critical section around find_module, following
> >> the lower level find_module_all helper, and switch the two callers
> >> outside of module.c to use such a RCU-sched critical section instead
> >> of module_mutex.
> >
> >That's a nice idea.
> >
> >> @@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object
> >> *obj)
> >>   if (!klp_is_module(obj))
> >>    return;
> >>
> >> -	mutex_lock(&module_mutex);
> >> +	rcu_read_lock_sched();
> >>   /*
> >>    * We do not want to block removal of patched modules and therefore
> >>    * we do not take a reference here. The patches are removed by
> >> @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object
> >> *obj)
> >>   if (mod && mod->klp_alive)
> >
> >RCU always baffles me a bit, so I'll ask. Don't we need
> >rcu_dereference_sched() here? "mod" comes from a RCU-protected list, so I
> >wonder.
> 
> Same here :-) I had to double check the RCU documentation. For our
> modules list case I believe the rcu list API should take care of that
> for us. Worth noting is this snippet from Documentation/RCU/whatisRCU.txt:
> 
>    rcu_dereference() is typically used indirectly, via the _rcu
>    list-manipulation primitives, such as list_for_each_entry_rcu()

Ok, thanks to both for checking and explanation.

Ack to the patch then.

Miroslav
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
  2021-02-01 11:47       ` Christoph Hellwig
  (?)
@ 2021-02-01 13:37         ` Miroslav Benes
  -1 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-01 13:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Jessica Yu, Josh Poimboeuf,
	Jiri Kosina, Joe Lawrence, Masahiro Yamada, Michal Marek,
	linux-kernel, linuxppc-dev, dri-devel, live-patching,
	linux-kbuild

On Mon, 1 Feb 2021, Christoph Hellwig wrote:

> On Fri, Jan 29, 2021 at 10:43:36AM +0100, Petr Mladek wrote:
> > > --- a/kernel/livepatch/core.c
> > > +++ b/kernel/livepatch/core.c
> > > @@ -164,12 +164,8 @@ static int klp_find_object_symbol(const char *objname, const char *name,
> > >  		.pos = sympos,
> > >  	};
> > >  
> > > -	mutex_lock(&module_mutex);
> > > -	if (objname)
> > > +	if (objname || !kallsyms_on_each_symbol(klp_find_callback, &args))
> > >  		module_kallsyms_on_each_symbol(klp_find_callback, &args);
> > > -	else
> > > -		kallsyms_on_each_symbol(klp_find_callback, &args);
> > > -	mutex_unlock(&module_mutex);
> > 
> > This change is not needed. (objname == NULL) means that we are
> > interested only in symbols in "vmlinux".
> > 
> > module_kallsyms_on_each_symbol(klp_find_callback, &args)
> > will always fail when objname == NULL.
> 
> I just tried to keep the old behavior.  I can respin it with your
> recommended change noting the change in behavior, though.

Yes, please. It would be cleaner that way.

Miroslav

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
@ 2021-02-01 13:37         ` Miroslav Benes
  0 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-01 13:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, linuxppc-dev

On Mon, 1 Feb 2021, Christoph Hellwig wrote:

> On Fri, Jan 29, 2021 at 10:43:36AM +0100, Petr Mladek wrote:
> > > --- a/kernel/livepatch/core.c
> > > +++ b/kernel/livepatch/core.c
> > > @@ -164,12 +164,8 @@ static int klp_find_object_symbol(const char *objname, const char *name,
> > >  		.pos = sympos,
> > >  	};
> > >  
> > > -	mutex_lock(&module_mutex);
> > > -	if (objname)
> > > +	if (objname || !kallsyms_on_each_symbol(klp_find_callback, &args))
> > >  		module_kallsyms_on_each_symbol(klp_find_callback, &args);
> > > -	else
> > > -		kallsyms_on_each_symbol(klp_find_callback, &args);
> > > -	mutex_unlock(&module_mutex);
> > 
> > This change is not needed. (objname == NULL) means that we are
> > interested only in symbols in "vmlinux".
> > 
> > module_kallsyms_on_each_symbol(klp_find_callback, &args)
> > will always fail when objname == NULL.
> 
> I just tried to keep the old behavior.  I can respin it with your
> recommended change noting the change in behavior, though.

Yes, please. It would be cleaner that way.

Miroslav

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
@ 2021-02-01 13:37         ` Miroslav Benes
  0 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-01 13:37 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, linux-kernel,
	live-patching, Michal Marek, Joe Lawrence, dri-devel,
	Thomas Zimmermann, Jessica Yu, Frederic Barrat, linuxppc-dev

On Mon, 1 Feb 2021, Christoph Hellwig wrote:

> On Fri, Jan 29, 2021 at 10:43:36AM +0100, Petr Mladek wrote:
> > > --- a/kernel/livepatch/core.c
> > > +++ b/kernel/livepatch/core.c
> > > @@ -164,12 +164,8 @@ static int klp_find_object_symbol(const char *objname, const char *name,
> > >  		.pos = sympos,
> > >  	};
> > >  
> > > -	mutex_lock(&module_mutex);
> > > -	if (objname)
> > > +	if (objname || !kallsyms_on_each_symbol(klp_find_callback, &args))
> > >  		module_kallsyms_on_each_symbol(klp_find_callback, &args);
> > > -	else
> > > -		kallsyms_on_each_symbol(klp_find_callback, &args);
> > > -	mutex_unlock(&module_mutex);
> > 
> > This change is not needed. (objname == NULL) means that we are
> > interested only in symbols in "vmlinux".
> > 
> > module_kallsyms_on_each_symbol(klp_find_callback, &args)
> > will always fail when objname == NULL.
> 
> I just tried to keep the old behavior.  I can respin it with your
> recommended change noting the change in behavior, though.

Yes, please. It would be cleaner that way.

Miroslav
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
  2021-01-28 18:14 ` [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol Christoph Hellwig
  2021-01-29  9:43   ` Petr Mladek
@ 2021-02-01 14:02     ` Miroslav Benes
  1 sibling, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-01 14:02 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Petr Mladek,
	Joe Lawrence, Masahiro Yamada, Michal Marek, linux-kernel,
	linuxppc-dev, dri-devel, live-patching, linux-kbuild

One more thing...

> @@ -4379,8 +4379,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
>  	unsigned int i;
>  	int ret;
>  
> -	module_assert_mutex();
> -
> +	mutex_lock(&module_mutex);
>  	list_for_each_entry(mod, &modules, list) {
>  		/* We hold module_mutex: no need for rcu_dereference_sched */
>  		struct mod_kallsyms *kallsyms = mod->kallsyms;

This was the last user of module_assert_mutex(), which can be removed now.

Miroslav

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
@ 2021-02-01 14:02     ` Miroslav Benes
  0 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-01 14:02 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, linuxppc-dev

One more thing...

> @@ -4379,8 +4379,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
>  	unsigned int i;
>  	int ret;
>  
> -	module_assert_mutex();
> -
> +	mutex_lock(&module_mutex);
>  	list_for_each_entry(mod, &modules, list) {
>  		/* We hold module_mutex: no need for rcu_dereference_sched */
>  		struct mod_kallsyms *kallsyms = mod->kallsyms;

This was the last user of module_assert_mutex(), which can be removed now.

Miroslav

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
@ 2021-02-01 14:02     ` Miroslav Benes
  0 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-01 14:02 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, linux-kernel,
	live-patching, Michal Marek, Joe Lawrence, dri-devel,
	Thomas Zimmermann, Jessica Yu, Frederic Barrat, linuxppc-dev

One more thing...

> @@ -4379,8 +4379,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
>  	unsigned int i;
>  	int ret;
>  
> -	module_assert_mutex();
> -
> +	mutex_lock(&module_mutex);
>  	list_for_each_entry(mod, &modules, list) {
>  		/* We hold module_mutex: no need for rcu_dereference_sched */
>  		struct mod_kallsyms *kallsyms = mod->kallsyms;

This was the last user of module_assert_mutex(), which can be removed now.

Miroslav
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
  2021-02-01 13:37         ` Miroslav Benes
@ 2021-02-01 16:28           ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-02-01 16:28 UTC (permalink / raw)
  To: Miroslav Benes
  Cc: Christoph Hellwig, Petr Mladek, Frederic Barrat,
	Andrew Donnellan, Maarten Lankhorst, Maxime Ripard,
	Thomas Zimmermann, David Airlie, Daniel Vetter, Jessica Yu,
	Josh Poimboeuf, Jiri Kosina, Joe Lawrence, Masahiro Yamada,
	Michal Marek, linux-kernel, linuxppc-dev, dri-devel,
	live-patching, linux-kbuild

On Mon, Feb 01, 2021 at 02:37:12PM +0100, Miroslav Benes wrote:
> > > This change is not needed. (objname == NULL) means that we are
> > > interested only in symbols in "vmlinux".
> > > 
> > > module_kallsyms_on_each_symbol(klp_find_callback, &args)
> > > will always fail when objname == NULL.
> > 
> > I just tried to keep the old behavior.  I can respin it with your
> > recommended change noting the change in behavior, though.
> 
> Yes, please. It would be cleaner that way.

Let me know if this works for you:

---
From 18af41e88d088cfb8680d1669fcae2bc2ede5328 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Wed, 20 Jan 2021 16:23:16 +0100
Subject: kallsyms: refactor {,module_}kallsyms_on_each_symbol

Require an explicit call to module_kallsyms_on_each_symbol to look
for symbols in modules instead of the call from kallsyms_on_each_symbol,
and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
of leaving that up to the caller.  Note that this slightly changes the
behavior for the livepatch code in that the symbols from vmlinux are not
iterated anymore if objname is set, but that actually is the desired
behavior in this case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/kallsyms.c       |  6 +++++-
 kernel/livepatch/core.c |  2 --
 kernel/module.c         | 13 ++++---------
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index fe9de067771c34..a0d3f0865916f9 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -177,6 +177,10 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+/*
+ * Iterate over all symbols in vmlinux.  For symbols from modules use
+ * module_kallsyms_on_each_symbol instead.
+ */
 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 				      unsigned long),
 			    void *data)
@@ -192,7 +196,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 		if (ret != 0)
 			return ret;
 	}
-	return module_kallsyms_on_each_symbol(fn, data);
+	return 0;
 }
 
 static unsigned long get_symbol_pos(unsigned long addr,
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 262cd9b003b9f0..335d988bd81117 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -164,12 +164,10 @@ static int klp_find_object_symbol(const char *objname, const char *name,
 		.pos = sympos,
 	};
 
-	mutex_lock(&module_mutex);
 	if (objname)
 		module_kallsyms_on_each_symbol(klp_find_callback, &args);
 	else
 		kallsyms_on_each_symbol(klp_find_callback, &args);
-	mutex_unlock(&module_mutex);
 
 	/*
 	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;
diff --git a/kernel/module.c b/kernel/module.c
index 6772fb2680eb3e..25345792c770d1 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -255,11 +255,6 @@ static void mod_update_bounds(struct module *mod)
 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 #endif /* CONFIG_KGDB_KDB */
 
-static void module_assert_mutex(void)
-{
-	lockdep_assert_held(&module_mutex);
-}
-
 static void module_assert_mutex_or_preempt(void)
 {
 #ifdef CONFIG_LOCKDEP
@@ -4379,8 +4374,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	unsigned int i;
 	int ret;
 
-	module_assert_mutex();
-
+	mutex_lock(&module_mutex);
 	list_for_each_entry(mod, &modules, list) {
 		/* We hold module_mutex: no need for rcu_dereference_sched */
 		struct mod_kallsyms *kallsyms = mod->kallsyms;
@@ -4396,10 +4390,11 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
 				 mod, kallsyms_symbol_value(sym));
 			if (ret != 0)
-				return ret;
+				break;
 		}
 	}
-	return 0;
+	mutex_unlock(&module_mutex);
+	return ret;
 }
 #endif /* CONFIG_KALLSYMS */
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
@ 2021-02-01 16:28           ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-02-01 16:28 UTC (permalink / raw)
  To: Miroslav Benes
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, linuxppc-dev, Christoph Hellwig

On Mon, Feb 01, 2021 at 02:37:12PM +0100, Miroslav Benes wrote:
> > > This change is not needed. (objname == NULL) means that we are
> > > interested only in symbols in "vmlinux".
> > > 
> > > module_kallsyms_on_each_symbol(klp_find_callback, &args)
> > > will always fail when objname == NULL.
> > 
> > I just tried to keep the old behavior.  I can respin it with your
> > recommended change noting the change in behavior, though.
> 
> Yes, please. It would be cleaner that way.

Let me know if this works for you:

---
From 18af41e88d088cfb8680d1669fcae2bc2ede5328 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Wed, 20 Jan 2021 16:23:16 +0100
Subject: kallsyms: refactor {,module_}kallsyms_on_each_symbol

Require an explicit call to module_kallsyms_on_each_symbol to look
for symbols in modules instead of the call from kallsyms_on_each_symbol,
and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
of leaving that up to the caller.  Note that this slightly changes the
behavior for the livepatch code in that the symbols from vmlinux are not
iterated anymore if objname is set, but that actually is the desired
behavior in this case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/kallsyms.c       |  6 +++++-
 kernel/livepatch/core.c |  2 --
 kernel/module.c         | 13 ++++---------
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index fe9de067771c34..a0d3f0865916f9 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -177,6 +177,10 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+/*
+ * Iterate over all symbols in vmlinux.  For symbols from modules use
+ * module_kallsyms_on_each_symbol instead.
+ */
 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 				      unsigned long),
 			    void *data)
@@ -192,7 +196,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 		if (ret != 0)
 			return ret;
 	}
-	return module_kallsyms_on_each_symbol(fn, data);
+	return 0;
 }
 
 static unsigned long get_symbol_pos(unsigned long addr,
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 262cd9b003b9f0..335d988bd81117 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -164,12 +164,10 @@ static int klp_find_object_symbol(const char *objname, const char *name,
 		.pos = sympos,
 	};
 
-	mutex_lock(&module_mutex);
 	if (objname)
 		module_kallsyms_on_each_symbol(klp_find_callback, &args);
 	else
 		kallsyms_on_each_symbol(klp_find_callback, &args);
-	mutex_unlock(&module_mutex);
 
 	/*
 	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;
diff --git a/kernel/module.c b/kernel/module.c
index 6772fb2680eb3e..25345792c770d1 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -255,11 +255,6 @@ static void mod_update_bounds(struct module *mod)
 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 #endif /* CONFIG_KGDB_KDB */
 
-static void module_assert_mutex(void)
-{
-	lockdep_assert_held(&module_mutex);
-}
-
 static void module_assert_mutex_or_preempt(void)
 {
 #ifdef CONFIG_LOCKDEP
@@ -4379,8 +4374,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	unsigned int i;
 	int ret;
 
-	module_assert_mutex();
-
+	mutex_lock(&module_mutex);
 	list_for_each_entry(mod, &modules, list) {
 		/* We hold module_mutex: no need for rcu_dereference_sched */
 		struct mod_kallsyms *kallsyms = mod->kallsyms;
@@ -4396,10 +4390,11 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
 				 mod, kallsyms_symbol_value(sym));
 			if (ret != 0)
-				return ret;
+				break;
 		}
 	}
-	return 0;
+	mutex_unlock(&module_mutex);
+	return ret;
 }
 #endif /* CONFIG_KALLSYMS */
 
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
  2021-02-01 16:28           ` Christoph Hellwig
  (?)
@ 2021-02-02 10:45             ` Miroslav Benes
  -1 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-02 10:45 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Jessica Yu, Josh Poimboeuf,
	Jiri Kosina, Joe Lawrence, Masahiro Yamada, Michal Marek,
	linux-kernel, linuxppc-dev, dri-devel, live-patching,
	linux-kbuild

On Mon, 1 Feb 2021, Christoph Hellwig wrote:

> On Mon, Feb 01, 2021 at 02:37:12PM +0100, Miroslav Benes wrote:
> > > > This change is not needed. (objname == NULL) means that we are
> > > > interested only in symbols in "vmlinux".
> > > > 
> > > > module_kallsyms_on_each_symbol(klp_find_callback, &args)
> > > > will always fail when objname == NULL.
> > > 
> > > I just tried to keep the old behavior.  I can respin it with your
> > > recommended change noting the change in behavior, though.
> > 
> > Yes, please. It would be cleaner that way.
> 
> Let me know if this works for you:
> 
> ---
> >From 18af41e88d088cfb8680d1669fcae2bc2ede5328 Mon Sep 17 00:00:00 2001
> From: Christoph Hellwig <hch@lst.de>
> Date: Wed, 20 Jan 2021 16:23:16 +0100
> Subject: kallsyms: refactor {,module_}kallsyms_on_each_symbol
> 
> Require an explicit call to module_kallsyms_on_each_symbol to look
> for symbols in modules instead of the call from kallsyms_on_each_symbol,
> and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
> of leaving that up to the caller.  Note that this slightly changes the
> behavior for the livepatch code in that the symbols from vmlinux are not
> iterated anymore if objname is set, but that actually is the desired
> behavior in this case.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Miroslav Benes <mbenes@suse.cz>

Thanks Christoph

M

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
@ 2021-02-02 10:45             ` Miroslav Benes
  0 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-02 10:45 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, linuxppc-dev

On Mon, 1 Feb 2021, Christoph Hellwig wrote:

> On Mon, Feb 01, 2021 at 02:37:12PM +0100, Miroslav Benes wrote:
> > > > This change is not needed. (objname == NULL) means that we are
> > > > interested only in symbols in "vmlinux".
> > > > 
> > > > module_kallsyms_on_each_symbol(klp_find_callback, &args)
> > > > will always fail when objname == NULL.
> > > 
> > > I just tried to keep the old behavior.  I can respin it with your
> > > recommended change noting the change in behavior, though.
> > 
> > Yes, please. It would be cleaner that way.
> 
> Let me know if this works for you:
> 
> ---
> >From 18af41e88d088cfb8680d1669fcae2bc2ede5328 Mon Sep 17 00:00:00 2001
> From: Christoph Hellwig <hch@lst.de>
> Date: Wed, 20 Jan 2021 16:23:16 +0100
> Subject: kallsyms: refactor {,module_}kallsyms_on_each_symbol
> 
> Require an explicit call to module_kallsyms_on_each_symbol to look
> for symbols in modules instead of the call from kallsyms_on_each_symbol,
> and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
> of leaving that up to the caller.  Note that this slightly changes the
> behavior for the livepatch code in that the symbols from vmlinux are not
> iterated anymore if objname is set, but that actually is the desired
> behavior in this case.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Miroslav Benes <mbenes@suse.cz>

Thanks Christoph

M

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
@ 2021-02-02 10:45             ` Miroslav Benes
  0 siblings, 0 replies; 69+ messages in thread
From: Miroslav Benes @ 2021-02-02 10:45 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, linux-kernel,
	live-patching, Michal Marek, Joe Lawrence, dri-devel,
	Thomas Zimmermann, Jessica Yu, Frederic Barrat, linuxppc-dev

On Mon, 1 Feb 2021, Christoph Hellwig wrote:

> On Mon, Feb 01, 2021 at 02:37:12PM +0100, Miroslav Benes wrote:
> > > > This change is not needed. (objname == NULL) means that we are
> > > > interested only in symbols in "vmlinux".
> > > > 
> > > > module_kallsyms_on_each_symbol(klp_find_callback, &args)
> > > > will always fail when objname == NULL.
> > > 
> > > I just tried to keep the old behavior.  I can respin it with your
> > > recommended change noting the change in behavior, though.
> > 
> > Yes, please. It would be cleaner that way.
> 
> Let me know if this works for you:
> 
> ---
> >From 18af41e88d088cfb8680d1669fcae2bc2ede5328 Mon Sep 17 00:00:00 2001
> From: Christoph Hellwig <hch@lst.de>
> Date: Wed, 20 Jan 2021 16:23:16 +0100
> Subject: kallsyms: refactor {,module_}kallsyms_on_each_symbol
> 
> Require an explicit call to module_kallsyms_on_each_symbol to look
> for symbols in modules instead of the call from kallsyms_on_each_symbol,
> and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
> of leaving that up to the caller.  Note that this slightly changes the
> behavior for the livepatch code in that the symbols from vmlinux are not
> iterated anymore if objname is set, but that actually is the desired
> behavior in this case.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Miroslav Benes <mbenes@suse.cz>

Thanks Christoph

M
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 02/13] drm: remove drm_fb_helper_modinit
  2021-01-28 18:14 ` [PATCH 02/13] drm: remove drm_fb_helper_modinit Christoph Hellwig
  2021-02-03 10:34     ` Daniel Vetter
@ 2021-02-03 10:34     ` Daniel Vetter
  0 siblings, 0 replies; 69+ messages in thread
From: Daniel Vetter @ 2021-02-03 10:34 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence, Masahiro Yamada, Michal Marek,
	linux-kernel, linuxppc-dev, dri-devel, live-patching,
	linux-kbuild

On Thu, Jan 28, 2021 at 07:14:10PM +0100, Christoph Hellwig wrote:
> drm_fb_helper_modinit has a lot of boilerplate for what is not very
> simple functionality.  Just open code it in the only caller using
> IS_ENABLED and IS_MODULE, and skip the find_module check as a
> request_module is harmless if the module is already loaded (and not
> other caller has this find_module check either).
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Hm I thought I've acked this one already somewhere for merging through
your tree.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/drm_crtc_helper_internal.h | 10 ---------
>  drivers/gpu/drm/drm_fb_helper.c            | 21 ------------------
>  drivers/gpu/drm/drm_kms_helper_common.c    | 25 +++++++++++-----------
>  3 files changed, 12 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h b/drivers/gpu/drm/drm_crtc_helper_internal.h
> index 25ce42e799952c..61e09f8a8d0ff0 100644
> --- a/drivers/gpu/drm/drm_crtc_helper_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
> @@ -32,16 +32,6 @@
>  #include <drm/drm_encoder.h>
>  #include <drm/drm_modes.h>
>  
> -/* drm_fb_helper.c */
> -#ifdef CONFIG_DRM_FBDEV_EMULATION
> -int drm_fb_helper_modinit(void);
> -#else
> -static inline int drm_fb_helper_modinit(void)
> -{
> -	return 0;
> -}
> -#endif
> -
>  /* drm_dp_aux_dev.c */
>  #ifdef CONFIG_DRM_DP_AUX_CHARDEV
>  int drm_dp_aux_dev_init(void);
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 4b81195106875d..0b9f1ae1b7864c 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -2499,24 +2499,3 @@ void drm_fbdev_generic_setup(struct drm_device *dev,
>  	drm_client_register(&fb_helper->client);
>  }
>  EXPORT_SYMBOL(drm_fbdev_generic_setup);
> -
> -/* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
> - * but the module doesn't depend on any fb console symbols.  At least
> - * attempt to load fbcon to avoid leaving the system without a usable console.
> - */
> -int __init drm_fb_helper_modinit(void)
> -{
> -#if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
> -	const char name[] = "fbcon";
> -	struct module *fbcon;
> -
> -	mutex_lock(&module_mutex);
> -	fbcon = find_module(name);
> -	mutex_unlock(&module_mutex);
> -
> -	if (!fbcon)
> -		request_module_nowait(name);
> -#endif
> -	return 0;
> -}
> -EXPORT_SYMBOL(drm_fb_helper_modinit);
> diff --git a/drivers/gpu/drm/drm_kms_helper_common.c b/drivers/gpu/drm/drm_kms_helper_common.c
> index 221a8528c9937a..f933da1656eb52 100644
> --- a/drivers/gpu/drm/drm_kms_helper_common.c
> +++ b/drivers/gpu/drm/drm_kms_helper_common.c
> @@ -64,19 +64,18 @@ MODULE_PARM_DESC(edid_firmware,
>  
>  static int __init drm_kms_helper_init(void)
>  {
> -	int ret;
> -
> -	/* Call init functions from specific kms helpers here */
> -	ret = drm_fb_helper_modinit();
> -	if (ret < 0)
> -		goto out;
> -
> -	ret = drm_dp_aux_dev_init();
> -	if (ret < 0)
> -		goto out;
> -
> -out:
> -	return ret;
> +	/*
> +	 * The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
> +	 * but the module doesn't depend on any fb console symbols.  At least
> +	 * attempt to load fbcon to avoid leaving the system without a usable
> +	 * console.
> +	 */
> +	if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) &&
> +	    IS_MODULE(CONFIG_FRAMEBUFFER_CONSOLE) &&
> +	    !IS_ENABLED(CONFIG_EXPERT))
> +		request_module_nowait("fbcon");
> +
> +	return drm_dp_aux_dev_init();
>  }
>  
>  static void __exit drm_kms_helper_exit(void)
> -- 
> 2.29.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 02/13] drm: remove drm_fb_helper_modinit
@ 2021-02-03 10:34     ` Daniel Vetter
  0 siblings, 0 replies; 69+ messages in thread
From: Daniel Vetter @ 2021-02-03 10:34 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, Maarten Lankhorst,
	linux-kernel, Maxime Ripard, live-patching, Michal Marek,
	Joe Lawrence, dri-devel, Thomas Zimmermann, Jessica Yu,
	Frederic Barrat, Daniel Vetter, Miroslav Benes, linuxppc-dev

On Thu, Jan 28, 2021 at 07:14:10PM +0100, Christoph Hellwig wrote:
> drm_fb_helper_modinit has a lot of boilerplate for what is not very
> simple functionality.  Just open code it in the only caller using
> IS_ENABLED and IS_MODULE, and skip the find_module check as a
> request_module is harmless if the module is already loaded (and not
> other caller has this find_module check either).
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Hm I thought I've acked this one already somewhere for merging through
your tree.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/drm_crtc_helper_internal.h | 10 ---------
>  drivers/gpu/drm/drm_fb_helper.c            | 21 ------------------
>  drivers/gpu/drm/drm_kms_helper_common.c    | 25 +++++++++++-----------
>  3 files changed, 12 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h b/drivers/gpu/drm/drm_crtc_helper_internal.h
> index 25ce42e799952c..61e09f8a8d0ff0 100644
> --- a/drivers/gpu/drm/drm_crtc_helper_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
> @@ -32,16 +32,6 @@
>  #include <drm/drm_encoder.h>
>  #include <drm/drm_modes.h>
>  
> -/* drm_fb_helper.c */
> -#ifdef CONFIG_DRM_FBDEV_EMULATION
> -int drm_fb_helper_modinit(void);
> -#else
> -static inline int drm_fb_helper_modinit(void)
> -{
> -	return 0;
> -}
> -#endif
> -
>  /* drm_dp_aux_dev.c */
>  #ifdef CONFIG_DRM_DP_AUX_CHARDEV
>  int drm_dp_aux_dev_init(void);
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 4b81195106875d..0b9f1ae1b7864c 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -2499,24 +2499,3 @@ void drm_fbdev_generic_setup(struct drm_device *dev,
>  	drm_client_register(&fb_helper->client);
>  }
>  EXPORT_SYMBOL(drm_fbdev_generic_setup);
> -
> -/* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
> - * but the module doesn't depend on any fb console symbols.  At least
> - * attempt to load fbcon to avoid leaving the system without a usable console.
> - */
> -int __init drm_fb_helper_modinit(void)
> -{
> -#if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
> -	const char name[] = "fbcon";
> -	struct module *fbcon;
> -
> -	mutex_lock(&module_mutex);
> -	fbcon = find_module(name);
> -	mutex_unlock(&module_mutex);
> -
> -	if (!fbcon)
> -		request_module_nowait(name);
> -#endif
> -	return 0;
> -}
> -EXPORT_SYMBOL(drm_fb_helper_modinit);
> diff --git a/drivers/gpu/drm/drm_kms_helper_common.c b/drivers/gpu/drm/drm_kms_helper_common.c
> index 221a8528c9937a..f933da1656eb52 100644
> --- a/drivers/gpu/drm/drm_kms_helper_common.c
> +++ b/drivers/gpu/drm/drm_kms_helper_common.c
> @@ -64,19 +64,18 @@ MODULE_PARM_DESC(edid_firmware,
>  
>  static int __init drm_kms_helper_init(void)
>  {
> -	int ret;
> -
> -	/* Call init functions from specific kms helpers here */
> -	ret = drm_fb_helper_modinit();
> -	if (ret < 0)
> -		goto out;
> -
> -	ret = drm_dp_aux_dev_init();
> -	if (ret < 0)
> -		goto out;
> -
> -out:
> -	return ret;
> +	/*
> +	 * The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
> +	 * but the module doesn't depend on any fb console symbols.  At least
> +	 * attempt to load fbcon to avoid leaving the system without a usable
> +	 * console.
> +	 */
> +	if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) &&
> +	    IS_MODULE(CONFIG_FRAMEBUFFER_CONSOLE) &&
> +	    !IS_ENABLED(CONFIG_EXPERT))
> +		request_module_nowait("fbcon");
> +
> +	return drm_dp_aux_dev_init();
>  }
>  
>  static void __exit drm_kms_helper_exit(void)
> -- 
> 2.29.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 02/13] drm: remove drm_fb_helper_modinit
@ 2021-02-03 10:34     ` Daniel Vetter
  0 siblings, 0 replies; 69+ messages in thread
From: Daniel Vetter @ 2021-02-03 10:34 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Petr Mladek, Jiri Kosina, Andrew Donnellan, linux-kbuild,
	David Airlie, Masahiro Yamada, Josh Poimboeuf, linux-kernel,
	live-patching, Michal Marek, Joe Lawrence, dri-devel,
	Thomas Zimmermann, Jessica Yu, Frederic Barrat, Miroslav Benes,
	linuxppc-dev

On Thu, Jan 28, 2021 at 07:14:10PM +0100, Christoph Hellwig wrote:
> drm_fb_helper_modinit has a lot of boilerplate for what is not very
> simple functionality.  Just open code it in the only caller using
> IS_ENABLED and IS_MODULE, and skip the find_module check as a
> request_module is harmless if the module is already loaded (and not
> other caller has this find_module check either).
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Hm I thought I've acked this one already somewhere for merging through
your tree.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/drm_crtc_helper_internal.h | 10 ---------
>  drivers/gpu/drm/drm_fb_helper.c            | 21 ------------------
>  drivers/gpu/drm/drm_kms_helper_common.c    | 25 +++++++++++-----------
>  3 files changed, 12 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h b/drivers/gpu/drm/drm_crtc_helper_internal.h
> index 25ce42e799952c..61e09f8a8d0ff0 100644
> --- a/drivers/gpu/drm/drm_crtc_helper_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
> @@ -32,16 +32,6 @@
>  #include <drm/drm_encoder.h>
>  #include <drm/drm_modes.h>
>  
> -/* drm_fb_helper.c */
> -#ifdef CONFIG_DRM_FBDEV_EMULATION
> -int drm_fb_helper_modinit(void);
> -#else
> -static inline int drm_fb_helper_modinit(void)
> -{
> -	return 0;
> -}
> -#endif
> -
>  /* drm_dp_aux_dev.c */
>  #ifdef CONFIG_DRM_DP_AUX_CHARDEV
>  int drm_dp_aux_dev_init(void);
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 4b81195106875d..0b9f1ae1b7864c 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -2499,24 +2499,3 @@ void drm_fbdev_generic_setup(struct drm_device *dev,
>  	drm_client_register(&fb_helper->client);
>  }
>  EXPORT_SYMBOL(drm_fbdev_generic_setup);
> -
> -/* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
> - * but the module doesn't depend on any fb console symbols.  At least
> - * attempt to load fbcon to avoid leaving the system without a usable console.
> - */
> -int __init drm_fb_helper_modinit(void)
> -{
> -#if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
> -	const char name[] = "fbcon";
> -	struct module *fbcon;
> -
> -	mutex_lock(&module_mutex);
> -	fbcon = find_module(name);
> -	mutex_unlock(&module_mutex);
> -
> -	if (!fbcon)
> -		request_module_nowait(name);
> -#endif
> -	return 0;
> -}
> -EXPORT_SYMBOL(drm_fb_helper_modinit);
> diff --git a/drivers/gpu/drm/drm_kms_helper_common.c b/drivers/gpu/drm/drm_kms_helper_common.c
> index 221a8528c9937a..f933da1656eb52 100644
> --- a/drivers/gpu/drm/drm_kms_helper_common.c
> +++ b/drivers/gpu/drm/drm_kms_helper_common.c
> @@ -64,19 +64,18 @@ MODULE_PARM_DESC(edid_firmware,
>  
>  static int __init drm_kms_helper_init(void)
>  {
> -	int ret;
> -
> -	/* Call init functions from specific kms helpers here */
> -	ret = drm_fb_helper_modinit();
> -	if (ret < 0)
> -		goto out;
> -
> -	ret = drm_dp_aux_dev_init();
> -	if (ret < 0)
> -		goto out;
> -
> -out:
> -	return ret;
> +	/*
> +	 * The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
> +	 * but the module doesn't depend on any fb console symbols.  At least
> +	 * attempt to load fbcon to avoid leaving the system without a usable
> +	 * console.
> +	 */
> +	if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) &&
> +	    IS_MODULE(CONFIG_FRAMEBUFFER_CONSOLE) &&
> +	    !IS_ENABLED(CONFIG_EXPERT))
> +		request_module_nowait("fbcon");
> +
> +	return drm_dp_aux_dev_init();
>  }
>  
>  static void __exit drm_kms_helper_exit(void)
> -- 
> 2.29.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 02/13] drm: remove drm_fb_helper_modinit
  2021-02-03 10:34     ` Daniel Vetter
  (?)
  (?)
@ 2021-02-03 10:49     ` Christoph Hellwig
  -1 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-02-03 10:49 UTC (permalink / raw)
  To: Christoph Hellwig, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Jessica Yu, Josh Poimboeuf, Jiri Kosina,
	Miroslav Benes, Petr Mladek, Joe Lawrence, Masahiro Yamada,
	Michal Marek, linux-kernel, linuxppc-dev, dri-devel,
	live-patching, linux-kbuild

On Wed, Feb 03, 2021 at 11:34:50AM +0100, Daniel Vetter wrote:
> On Thu, Jan 28, 2021 at 07:14:10PM +0100, Christoph Hellwig wrote:
> > drm_fb_helper_modinit has a lot of boilerplate for what is not very
> > simple functionality.  Just open code it in the only caller using
> > IS_ENABLED and IS_MODULE, and skip the find_module check as a
> > request_module is harmless if the module is already loaded (and not
> > other caller has this find_module check either).
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> Hm I thought I've acked this one already somewhere for merging through
> your tree.
> 
> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The difference is that this new version loses the find_module entirely,
while the previous one replaced it with the module_loaded helper that
didn't make it to the second version of the series.

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 01/13] powerpc/powernv: remove get_cxl_module
  2021-02-02 12:13   ` Christoph Hellwig
  (?)
@ 2021-02-04 10:44     ` Michael Ellerman
  -1 siblings, 0 replies; 69+ messages in thread
From: Michael Ellerman @ 2021-02-04 10:44 UTC (permalink / raw)
  To: Christoph Hellwig, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Jessica Yu, Josh Poimboeuf,
	Jiri Kosina, Miroslav Benes, Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

Christoph Hellwig <hch@lst.de> writes:
> The static inline get_cxl_module function is entirely unused since commit
> 8bf6b91a5125a ("Revert "powerpc/powernv: Add support for the cxl kernel
> api on the real phb"), so remove it.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
>  arch/powerpc/platforms/powernv/pci-cxl.c | 22 ----------------------
>  1 file changed, 22 deletions(-)

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheers

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 01/13] powerpc/powernv: remove get_cxl_module
@ 2021-02-04 10:44     ` Michael Ellerman
  0 siblings, 0 replies; 69+ messages in thread
From: Michael Ellerman @ 2021-02-04 10:44 UTC (permalink / raw)
  To: Christoph Hellwig, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Jessica Yu, Josh Poimboeuf,
	Jiri Kosina, Miroslav Benes, Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

Christoph Hellwig <hch@lst.de> writes:
> The static inline get_cxl_module function is entirely unused since commit
> 8bf6b91a5125a ("Revert "powerpc/powernv: Add support for the cxl kernel
> api on the real phb"), so remove it.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
>  arch/powerpc/platforms/powernv/pci-cxl.c | 22 ----------------------
>  1 file changed, 22 deletions(-)

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheers

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 01/13] powerpc/powernv: remove get_cxl_module
@ 2021-02-04 10:44     ` Michael Ellerman
  0 siblings, 0 replies; 69+ messages in thread
From: Michael Ellerman @ 2021-02-04 10:44 UTC (permalink / raw)
  To: Christoph Hellwig, Frederic Barrat, Andrew Donnellan,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Jessica Yu, Josh Poimboeuf,
	Jiri Kosina, Miroslav Benes, Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

Christoph Hellwig <hch@lst.de> writes:
> The static inline get_cxl_module function is entirely unused since commit
> 8bf6b91a5125a ("Revert "powerpc/powernv: Add support for the cxl kernel
> api on the real phb"), so remove it.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
>  arch/powerpc/platforms/powernv/pci-cxl.c | 22 ----------------------
>  1 file changed, 22 deletions(-)

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheers
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 01/13] powerpc/powernv: remove get_cxl_module
  2021-02-02 12:13 module loader dead code removal and cleanups v3 Christoph Hellwig
@ 2021-02-02 12:13   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-02-02 12:13 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

The static inline get_cxl_module function is entirely unused since commit
8bf6b91a5125a ("Revert "powerpc/powernv: Add support for the cxl kernel
api on the real phb"), so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
---
 arch/powerpc/platforms/powernv/pci-cxl.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-cxl.c b/arch/powerpc/platforms/powernv/pci-cxl.c
index 8c739c94ed28d6..53172862d23bd3 100644
--- a/arch/powerpc/platforms/powernv/pci-cxl.c
+++ b/arch/powerpc/platforms/powernv/pci-cxl.c
@@ -150,25 +150,3 @@ int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
 	return 0;
 }
 EXPORT_SYMBOL(pnv_cxl_ioda_msi_setup);
-
-#if IS_MODULE(CONFIG_CXL)
-static inline int get_cxl_module(void)
-{
-	struct module *cxl_module;
-
-	mutex_lock(&module_mutex);
-
-	cxl_module = find_module("cxl");
-	if (cxl_module)
-		__module_get(cxl_module);
-
-	mutex_unlock(&module_mutex);
-
-	if (!cxl_module)
-		return -ENODEV;
-
-	return 0;
-}
-#else
-static inline int get_cxl_module(void) { return 0; }
-#endif
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 01/13] powerpc/powernv: remove get_cxl_module
@ 2021-02-02 12:13   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-02-02 12:13 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

The static inline get_cxl_module function is entirely unused since commit
8bf6b91a5125a ("Revert "powerpc/powernv: Add support for the cxl kernel
api on the real phb"), so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
---
 arch/powerpc/platforms/powernv/pci-cxl.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-cxl.c b/arch/powerpc/platforms/powernv/pci-cxl.c
index 8c739c94ed28d6..53172862d23bd3 100644
--- a/arch/powerpc/platforms/powernv/pci-cxl.c
+++ b/arch/powerpc/platforms/powernv/pci-cxl.c
@@ -150,25 +150,3 @@ int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
 	return 0;
 }
 EXPORT_SYMBOL(pnv_cxl_ioda_msi_setup);
-
-#if IS_MODULE(CONFIG_CXL)
-static inline int get_cxl_module(void)
-{
-	struct module *cxl_module;
-
-	mutex_lock(&module_mutex);
-
-	cxl_module = find_module("cxl");
-	if (cxl_module)
-		__module_get(cxl_module);
-
-	mutex_unlock(&module_mutex);
-
-	if (!cxl_module)
-		return -ENODEV;
-
-	return 0;
-}
-#else
-static inline int get_cxl_module(void) { return 0; }
-#endif
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 01/13] powerpc/powernv: remove get_cxl_module
  2021-01-21  7:49   ` Christoph Hellwig
  (?)
@ 2021-01-21  9:09     ` Andrew Donnellan
  -1 siblings, 0 replies; 69+ messages in thread
From: Andrew Donnellan @ 2021-01-21  9:09 UTC (permalink / raw)
  To: Christoph Hellwig, Frederic Barrat, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

On 21/1/21 6:49 pm, Christoph Hellwig wrote:
> The static inline get_cxl_module function is entirely unused,
> remove it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

The one user of this was removed in 8bf6b91a5125a ("Revert 
"powerpc/powernv: Add support for the cxl kernel api on the real phb").

Thanks for picking this up.

Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 01/13] powerpc/powernv: remove get_cxl_module
@ 2021-01-21  9:09     ` Andrew Donnellan
  0 siblings, 0 replies; 69+ messages in thread
From: Andrew Donnellan @ 2021-01-21  9:09 UTC (permalink / raw)
  To: Christoph Hellwig, Frederic Barrat, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

On 21/1/21 6:49 pm, Christoph Hellwig wrote:
> The static inline get_cxl_module function is entirely unused,
> remove it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

The one user of this was removed in 8bf6b91a5125a ("Revert 
"powerpc/powernv: Add support for the cxl kernel api on the real phb").

Thanks for picking this up.

Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited

^ permalink raw reply	[flat|nested] 69+ messages in thread

* Re: [PATCH 01/13] powerpc/powernv: remove get_cxl_module
@ 2021-01-21  9:09     ` Andrew Donnellan
  0 siblings, 0 replies; 69+ messages in thread
From: Andrew Donnellan @ 2021-01-21  9:09 UTC (permalink / raw)
  To: Christoph Hellwig, Frederic Barrat, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

On 21/1/21 6:49 pm, Christoph Hellwig wrote:
> The static inline get_cxl_module function is entirely unused,
> remove it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

The one user of this was removed in 8bf6b91a5125a ("Revert 
"powerpc/powernv: Add support for the cxl kernel api on the real phb").

Thanks for picking this up.

Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 01/13] powerpc/powernv: remove get_cxl_module
  2021-01-21  7:49 module loader dead code removal and cleanusp Christoph Hellwig
@ 2021-01-21  7:49   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-21  7:49 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Masahiro Yamada, Michal Marek, linux-kernel, linuxppc-dev,
	dri-devel, live-patching, linux-kbuild

The static inline get_cxl_module function is entirely unused,
remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/powerpc/platforms/powernv/pci-cxl.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-cxl.c b/arch/powerpc/platforms/powernv/pci-cxl.c
index 8c739c94ed28d6..53172862d23bd3 100644
--- a/arch/powerpc/platforms/powernv/pci-cxl.c
+++ b/arch/powerpc/platforms/powernv/pci-cxl.c
@@ -150,25 +150,3 @@ int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
 	return 0;
 }
 EXPORT_SYMBOL(pnv_cxl_ioda_msi_setup);
-
-#if IS_MODULE(CONFIG_CXL)
-static inline int get_cxl_module(void)
-{
-	struct module *cxl_module;
-
-	mutex_lock(&module_mutex);
-
-	cxl_module = find_module("cxl");
-	if (cxl_module)
-		__module_get(cxl_module);
-
-	mutex_unlock(&module_mutex);
-
-	if (!cxl_module)
-		return -ENODEV;
-
-	return 0;
-}
-#else
-static inline int get_cxl_module(void) { return 0; }
-#endif
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

* [PATCH 01/13] powerpc/powernv: remove get_cxl_module
@ 2021-01-21  7:49   ` Christoph Hellwig
  0 siblings, 0 replies; 69+ messages in thread
From: Christoph Hellwig @ 2021-01-21  7:49 UTC (permalink / raw)
  To: Frederic Barrat, Andrew Donnellan, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Jessica Yu, Josh Poimboeuf, Jiri Kosina, Miroslav Benes,
	Petr Mladek, Joe Lawrence
  Cc: Michal Marek, linux-kbuild, Masahiro Yamada, linux-kernel,
	dri-devel, live-patching, linuxppc-dev

The static inline get_cxl_module function is entirely unused,
remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/powerpc/platforms/powernv/pci-cxl.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-cxl.c b/arch/powerpc/platforms/powernv/pci-cxl.c
index 8c739c94ed28d6..53172862d23bd3 100644
--- a/arch/powerpc/platforms/powernv/pci-cxl.c
+++ b/arch/powerpc/platforms/powernv/pci-cxl.c
@@ -150,25 +150,3 @@ int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
 	return 0;
 }
 EXPORT_SYMBOL(pnv_cxl_ioda_msi_setup);
-
-#if IS_MODULE(CONFIG_CXL)
-static inline int get_cxl_module(void)
-{
-	struct module *cxl_module;
-
-	mutex_lock(&module_mutex);
-
-	cxl_module = find_module("cxl");
-	if (cxl_module)
-		__module_get(cxl_module);
-
-	mutex_unlock(&module_mutex);
-
-	if (!cxl_module)
-		return -ENODEV;
-
-	return 0;
-}
-#else
-static inline int get_cxl_module(void) { return 0; }
-#endif
-- 
2.29.2


^ permalink raw reply	[flat|nested] 69+ messages in thread

end of thread, other threads:[~2021-02-04 11:21 UTC | newest]

Thread overview: 69+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-01-28 18:14 module loader dead code removal and cleanups v2 Christoph Hellwig
2021-01-28 18:14 ` Christoph Hellwig
2021-01-28 18:14 ` [PATCH 01/13] powerpc/powernv: remove get_cxl_module Christoph Hellwig
2021-01-28 18:14   ` Christoph Hellwig
2021-01-28 18:14 ` [PATCH 02/13] drm: remove drm_fb_helper_modinit Christoph Hellwig
2021-02-03 10:34   ` Daniel Vetter
2021-02-03 10:34     ` Daniel Vetter
2021-02-03 10:34     ` Daniel Vetter
2021-02-03 10:49     ` Christoph Hellwig
2021-01-28 18:14 ` [PATCH 03/13] module: unexport find_module and module_mutex Christoph Hellwig
2021-01-28 18:14   ` Christoph Hellwig
2021-01-29 15:16   ` Miroslav Benes
2021-01-28 18:14 ` [PATCH 04/13] module: use RCU to synchronize find_module Christoph Hellwig
2021-01-28 18:14   ` Christoph Hellwig
2021-01-28 20:50   ` Thiago Jung Bauermann
2021-01-28 20:50     ` Thiago Jung Bauermann
2021-01-28 20:50     ` Thiago Jung Bauermann
2021-01-29  5:10     ` Christoph Hellwig
2021-01-29  5:10       ` Christoph Hellwig
2021-01-29 21:29       ` Thiago Jung Bauermann
2021-01-29 21:29         ` Thiago Jung Bauermann
2021-01-29 10:04   ` Petr Mladek
2021-01-29 10:04     ` Petr Mladek
2021-01-29 15:29   ` Miroslav Benes
2021-02-01 11:46     ` Christoph Hellwig
2021-02-01 11:46       ` Christoph Hellwig
2021-02-01 12:10     ` Jessica Yu
2021-02-01 12:10       ` Jessica Yu
2021-02-01 12:10       ` Jessica Yu
2021-02-01 13:16       ` Miroslav Benes
2021-02-01 13:16         ` Miroslav Benes
2021-02-01 13:16         ` Miroslav Benes
2021-01-28 18:14 ` [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol Christoph Hellwig
2021-01-29  9:43   ` Petr Mladek
2021-02-01 11:47     ` Christoph Hellwig
2021-02-01 11:47       ` Christoph Hellwig
2021-02-01 13:37       ` Miroslav Benes
2021-02-01 13:37         ` Miroslav Benes
2021-02-01 13:37         ` Miroslav Benes
2021-02-01 16:28         ` Christoph Hellwig
2021-02-01 16:28           ` Christoph Hellwig
2021-02-02 10:45           ` Miroslav Benes
2021-02-02 10:45             ` Miroslav Benes
2021-02-02 10:45             ` Miroslav Benes
2021-02-01 14:02   ` Miroslav Benes
2021-02-01 14:02     ` Miroslav Benes
2021-02-01 14:02     ` Miroslav Benes
2021-01-28 18:14 ` [PATCH 06/13] kallsyms: only build {, module_}kallsyms_on_each_symbol when required Christoph Hellwig
2021-01-28 18:14 ` [PATCH 07/13] module: mark module_mutex static Christoph Hellwig
2021-01-28 18:14   ` Christoph Hellwig
2021-01-28 18:14 ` [PATCH 08/13] module: remove each_symbol_in_section Christoph Hellwig
2021-01-28 18:14 ` [PATCH 09/13] module: merge each_symbol_section into find_symbol Christoph Hellwig
2021-01-28 18:14 ` [PATCH 10/13] module: pass struct find_symbol_args to find_symbol Christoph Hellwig
2021-01-28 18:14   ` Christoph Hellwig
2021-01-28 18:14 ` [PATCH 11/13] module: move struct symsearch to module.c Christoph Hellwig
2021-01-28 18:14   ` Christoph Hellwig
2021-01-28 18:14 ` [PATCH 12/13] module: remove EXPORT_SYMBOL_GPL_FUTURE Christoph Hellwig
2021-01-28 18:14   ` Christoph Hellwig
2021-01-28 18:14 ` [PATCH 13/13] module: remove EXPORT_UNUSED_SYMBOL* Christoph Hellwig
  -- strict thread matches above, loose matches on Subject: below --
2021-02-02 12:13 module loader dead code removal and cleanups v3 Christoph Hellwig
2021-02-02 12:13 ` [PATCH 01/13] powerpc/powernv: remove get_cxl_module Christoph Hellwig
2021-02-02 12:13   ` Christoph Hellwig
2021-02-04 10:44   ` Michael Ellerman
2021-02-04 10:44     ` Michael Ellerman
2021-02-04 10:44     ` Michael Ellerman
2021-01-21  7:49 module loader dead code removal and cleanusp Christoph Hellwig
2021-01-21  7:49 ` [PATCH 01/13] powerpc/powernv: remove get_cxl_module Christoph Hellwig
2021-01-21  7:49   ` Christoph Hellwig
2021-01-21  9:09   ` Andrew Donnellan
2021-01-21  9:09     ` Andrew Donnellan
2021-01-21  9:09     ` Andrew Donnellan

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