[PATCH 0/3] further BKL removal

[PATCH 0/3] further BKL removal

[Arnd Bergmann]

With the ioctl, block, tty, vfs and llseek series
on their way into linux-next, these three patches
are attacking the hardest remaining issues.

If we get these ready for 2.6.36, the kernel should
be almost usable with the BKL disabled. In all three
cases, I'm cheating a bit, because the BKL still
remains lurking in the dark corners of the three
subsystems (i810/i830 for drm, OSS for sound and
lockd for fs/locks.c).

	Arnd

Cc: Christoph Hellwig <hch@lst.de>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: alsa-devel@alsa-project.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Arnd Bergmann (2):
  drm: kill BKL from common code
  sound: push BKL into open functions

Matthew Wilcox (1):
  Remove BKL from fs/locks.c

 arch/um/drivers/hostaudio_kern.c   |    6 ++
 drivers/gpu/drm/drm_drv.c          |    4 +-
 drivers/gpu/drm/drm_fops.c         |   23 ++++----
 drivers/gpu/drm/i810/i810_dma.c    |   44 +++++++++-----
 drivers/gpu/drm/i810/i810_drv.c    |    2 +-
 drivers/gpu/drm/i810/i810_drv.h    |    1 +
 drivers/gpu/drm/i830/i830_dma.c    |   42 +++++++++----
 drivers/gpu/drm/i830/i830_drv.c    |    2 +-
 drivers/gpu/drm/i830/i830_drv.h    |    1 +
 fs/Kconfig                         |    4 +
 fs/locks.c                         |  116 ++++++++++++++++++++++--------------
 include/drm/drmP.h                 |    2 +-
 sound/core/hwdep.c                 |   14 +++-
 sound/core/oss/mixer_oss.c         |   19 ++++---
 sound/oss/au1550_ac97.c            |   26 +++++---
 sound/oss/dmasound/dmasound_core.c |   28 +++++++--
 sound/oss/msnd_pinnacle.c          |   10 ++-
 sound/oss/sh_dac_audio.c           |    9 ++-
 sound/oss/soundcard.c              |   20 ++++---
 sound/oss/swarm_cs4297a.c          |   17 +++++-
 sound/oss/vwsnd.c                  |    8 +++
 sound/sound_core.c                 |    6 +--
 22 files changed, 267 insertions(+), 137 deletions(-)

[PATCH 1/3] drm: kill BKL from common code

[Arnd Bergmann]

This restricts the use of the big kernel lock to the i830 and i810
device drivers. The three remaining users in common code (open, ioctl
and release) get converted to a new mutex, the drm_global_mutex,
making the locking stricter than the big kernel lock.

This may have a performance impact, but only in those cases that
currently don't use DRM_UNLOCKED flag in the ioctl list and would
benefit from that anyway.

The reason why i810 and i830 cannot use drm_global_mutex in their
mmap functions is a lock-order inversion problem between the current
use of the BKL and mmap_sem in these drivers. Since the BKL has
release-on-sleep semantics, it's harmless but it would cause trouble
if we replace the BKL with a mutex.

Instead, these drivers get their own ioctl wrappers that take the
BKL around every ioctl call and then set their own handlers as
DRM_UNLOCKED.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
---
 drivers/gpu/drm/drm_drv.c       |    4 +-
 drivers/gpu/drm/drm_fops.c      |   23 +++++++++----------
 drivers/gpu/drm/i810/i810_dma.c |   44 +++++++++++++++++++++++++-------------
 drivers/gpu/drm/i810/i810_drv.c |    2 +-
 drivers/gpu/drm/i810/i810_drv.h |    1 +
 drivers/gpu/drm/i830/i830_dma.c |   42 ++++++++++++++++++++++++------------
 drivers/gpu/drm/i830/i830_drv.c |    2 +-
 drivers/gpu/drm/i830/i830_drv.h |    1 +
 include/drm/drmP.h              |    2 +-
 9 files changed, 75 insertions(+), 46 deletions(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 4a66201..76d98f4 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -506,9 +506,9 @@ long drm_ioctl(struct file *filp,
 		if (ioctl->flags & DRM_UNLOCKED)
 			retcode = func(dev, kdata, file_priv);
 		else {
-			lock_kernel();
+			mutex_lock(&drm_global_mutex);
 			retcode = func(dev, kdata, file_priv);
-			unlock_kernel();
+			mutex_unlock(&drm_global_mutex);
 		}
 
 		if (cmd & IOC_OUT) {
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index e7aace2..2ca8df8 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -39,6 +39,9 @@
 #include <linux/slab.h>
 #include <linux/smp_lock.h>
 
+/* from BKL pushdown: note that nothing else serializes idr_find() */
+DEFINE_MUTEX(drm_global_mutex);
+
 static int drm_open_helper(struct inode *inode, struct file *filp,
 			   struct drm_device * dev);
 
@@ -175,8 +178,7 @@ int drm_stub_open(struct inode *inode, struct file *filp)
 
 	DRM_DEBUG("\n");
 
-	/* BKL pushdown: note that nothing else serializes idr_find() */
-	lock_kernel();
+	mutex_lock(&drm_global_mutex);
 	minor = idr_find(&drm_minors_idr, minor_id);
 	if (!minor)
 		goto out;
@@ -197,7 +199,7 @@ int drm_stub_open(struct inode *inode, struct file *filp)
 	fops_put(old_fops);
 
 out:
-	unlock_kernel();
+	mutex_unlock(&drm_global_mutex);
 	return err;
 }
 
@@ -472,7 +474,7 @@ int drm_release(struct inode *inode, struct file *filp)
 	struct drm_device *dev = file_priv->minor->dev;
 	int retcode = 0;
 
-	lock_kernel();
+	mutex_lock(&drm_global_mutex);
 
 	DRM_DEBUG("open_count = %d\n", dev->open_count);
 
@@ -573,17 +575,14 @@ int drm_release(struct inode *inode, struct file *filp)
 		if (atomic_read(&dev->ioctl_count)) {
 			DRM_ERROR("Device busy: %d\n",
 				  atomic_read(&dev->ioctl_count));
-			spin_unlock(&dev->count_lock);
-			unlock_kernel();
-			return -EBUSY;
+			retcode = -EBUSY;
+			goto out;
 		}
-		spin_unlock(&dev->count_lock);
-		unlock_kernel();
-		return drm_lastclose(dev);
+		retcode = drm_lastclose(dev);
 	}
+out:
 	spin_unlock(&dev->count_lock);
-
-	unlock_kernel();
+	mutex_unlock(&drm_global_mutex);
 
 	return retcode;
 }
diff --git a/drivers/gpu/drm/i810/i810_dma.c b/drivers/gpu/drm/i810/i810_dma.c
index 997d917..0090693 100644
--- a/drivers/gpu/drm/i810/i810_dma.c
+++ b/drivers/gpu/drm/i810/i810_dma.c
@@ -37,6 +37,7 @@
 #include <linux/interrupt.h>	/* For task queue support */
 #include <linux/delay.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <linux/pagemap.h>
 
 #define I810_BUF_FREE		2
@@ -1245,22 +1246,35 @@ int i810_driver_dma_quiescent(struct drm_device * dev)
 	return 0;
 }
 
+/*
+ * call the drm_ioctl under the big kernel lock because
+ * to lock against the i810_mmap_buffers function.
+ */
+long i810_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int ret;
+	lock_kernel();
+	ret = drm_ioctl(file, cmd, arg);
+	unlock_kernel();
+	return ret;
+}
+
 struct drm_ioctl_desc i810_ioctls[] = {
-	DRM_IOCTL_DEF(DRM_I810_INIT, i810_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
-	DRM_IOCTL_DEF(DRM_I810_VERTEX, i810_dma_vertex, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_CLEAR, i810_clear_bufs, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_FLUSH, i810_flush_ioctl, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_GETAGE, i810_getage, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_GETBUF, i810_getbuf, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_SWAP, i810_swap_bufs, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_COPY, i810_copybuf, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_DOCOPY, i810_docopy, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_OV0INFO, i810_ov0_info, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_FSTATUS, i810_fstatus, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_OV0FLIP, i810_ov0_flip, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_MC, i810_dma_mc, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
-	DRM_IOCTL_DEF(DRM_I810_RSTATUS, i810_rstatus, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I810_FLIP, i810_flip_bufs, DRM_AUTH)
+	DRM_IOCTL_DEF(DRM_I810_INIT, i810_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_VERTEX, i810_dma_vertex, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_CLEAR, i810_clear_bufs, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_FLUSH, i810_flush_ioctl, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_GETAGE, i810_getage, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_GETBUF, i810_getbuf, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_SWAP, i810_swap_bufs, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_COPY, i810_copybuf, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_DOCOPY, i810_docopy, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_OV0INFO, i810_ov0_info, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_FSTATUS, i810_fstatus, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_OV0FLIP, i810_ov0_flip, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_MC, i810_dma_mc, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_RSTATUS, i810_rstatus, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I810_FLIP, i810_flip_bufs, DRM_AUTH|DRM_UNLOCKED),
 };
 
 int i810_max_ioctl = DRM_ARRAY_SIZE(i810_ioctls);
diff --git a/drivers/gpu/drm/i810/i810_drv.c b/drivers/gpu/drm/i810/i810_drv.c
index c1e0275..b4250b2 100644
--- a/drivers/gpu/drm/i810/i810_drv.c
+++ b/drivers/gpu/drm/i810/i810_drv.c
@@ -59,7 +59,7 @@ static struct drm_driver driver = {
 		 .owner = THIS_MODULE,
 		 .open = drm_open,
 		 .release = drm_release,
-		 .unlocked_ioctl = drm_ioctl,
+		 .unlocked_ioctl = i810_ioctl,
 		 .mmap = drm_mmap,
 		 .poll = drm_poll,
 		 .fasync = drm_fasync,
diff --git a/drivers/gpu/drm/i810/i810_drv.h b/drivers/gpu/drm/i810/i810_drv.h
index 21e2691..cac8f37 100644
--- a/drivers/gpu/drm/i810/i810_drv.h
+++ b/drivers/gpu/drm/i810/i810_drv.h
@@ -126,6 +126,7 @@ extern void i810_driver_reclaim_buffers_locked(struct drm_device * dev,
 					       struct drm_file *file_priv);
 extern int i810_driver_device_is_agp(struct drm_device * dev);
 
+extern long i810_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 extern struct drm_ioctl_desc i810_ioctls[];
 extern int i810_max_ioctl;
 
diff --git a/drivers/gpu/drm/i830/i830_dma.c b/drivers/gpu/drm/i830/i830_dma.c
index 65759a9..7a31d71 100644
--- a/drivers/gpu/drm/i830/i830_dma.c
+++ b/drivers/gpu/drm/i830/i830_dma.c
@@ -36,6 +36,7 @@
 #include "i830_drm.h"
 #include "i830_drv.h"
 #include <linux/interrupt.h>	/* For task queue support */
+#include <linux/smp_lock.h>
 #include <linux/pagemap.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
@@ -1516,21 +1517,34 @@ int i830_driver_dma_quiescent(struct drm_device * dev)
 	return 0;
 }
 
+/*
+ * call the drm_ioctl under the big kernel lock because
+ * to lock against the i830_mmap_buffers function.
+ */
+long i830_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int ret;
+	lock_kernel();
+	ret = drm_ioctl(file, cmd, arg);
+	unlock_kernel();
+	return ret;
+}
+
 struct drm_ioctl_desc i830_ioctls[] = {
-	DRM_IOCTL_DEF(DRM_I830_INIT, i830_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
-	DRM_IOCTL_DEF(DRM_I830_VERTEX, i830_dma_vertex, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_CLEAR, i830_clear_bufs, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_FLUSH, i830_flush_ioctl, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_GETAGE, i830_getage, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_GETBUF, i830_getbuf, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_SWAP, i830_swap_bufs, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_COPY, i830_copybuf, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_DOCOPY, i830_docopy, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_FLIP, i830_flip_bufs, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_IRQ_EMIT, i830_irq_emit, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_IRQ_WAIT, i830_irq_wait, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_GETPARAM, i830_getparam, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I830_SETPARAM, i830_setparam, DRM_AUTH)
+	DRM_IOCTL_DEF(DRM_I830_INIT, i830_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_VERTEX, i830_dma_vertex, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_CLEAR, i830_clear_bufs, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_FLUSH, i830_flush_ioctl, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_GETAGE, i830_getage, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_GETBUF, i830_getbuf, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_SWAP, i830_swap_bufs, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_COPY, i830_copybuf, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_DOCOPY, i830_docopy, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_FLIP, i830_flip_bufs, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_IRQ_EMIT, i830_irq_emit, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_IRQ_WAIT, i830_irq_wait, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_GETPARAM, i830_getparam, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_I830_SETPARAM, i830_setparam, DRM_AUTH|DRM_UNLOCKED),
 };
 
 int i830_max_ioctl = DRM_ARRAY_SIZE(i830_ioctls);
diff --git a/drivers/gpu/drm/i830/i830_drv.c b/drivers/gpu/drm/i830/i830_drv.c
index 44f990b..a5c66aa 100644
--- a/drivers/gpu/drm/i830/i830_drv.c
+++ b/drivers/gpu/drm/i830/i830_drv.c
@@ -70,7 +70,7 @@ static struct drm_driver driver = {
 		 .owner = THIS_MODULE,
 		 .open = drm_open,
 		 .release = drm_release,
-		 .unlocked_ioctl = drm_ioctl,
+		 .unlocked_ioctl = i830_ioctl,
 		 .mmap = drm_mmap,
 		 .poll = drm_poll,
 		 .fasync = drm_fasync,
diff --git a/drivers/gpu/drm/i830/i830_drv.h b/drivers/gpu/drm/i830/i830_drv.h
index da82afe..d8df717 100644
--- a/drivers/gpu/drm/i830/i830_drv.h
+++ b/drivers/gpu/drm/i830/i830_drv.h
@@ -122,6 +122,7 @@ typedef struct drm_i830_private {
 
 } drm_i830_private_t;
 
+long i830_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 extern struct drm_ioctl_desc i830_ioctls[];
 extern int i830_max_ioctl;
 
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index c1b9871..cd0e56b 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -50,7 +50,6 @@
 #include <linux/file.h>
 #include <linux/pci.h>
 #include <linux/jiffies.h>
-#include <linux/smp_lock.h>	/* For (un)lock_kernel */
 #include <linux/dma-mapping.h>
 #include <linux/mm.h>
 #include <linux/cdev.h>
@@ -1138,6 +1137,7 @@ extern long drm_compat_ioctl(struct file *filp,
 extern int drm_lastclose(struct drm_device *dev);
 
 				/* Device support (drm_fops.h) */
+extern struct mutex drm_global_mutex;
 extern int drm_open(struct inode *inode, struct file *filp);
 extern int drm_stub_open(struct inode *inode, struct file *filp);
 extern int drm_fasync(int fd, struct file *filp, int on);
-- 
1.7.1

[PATCH 2/3] Remove BKL from fs/locks.c

[Arnd Bergmann]

From: Matthew Wilcox <willy@linux.intel.com>

I've taken a patch originally written by Matthew Wilcox and
ported it to the current version. Unfortunately, the change
conflicts with the use of lockd, which still heavily uses
the big kernel lock.

As a workaround, I've made the behaviour configurable,
it either uses the BKL when it's enabled or a spinlock
when the BKL (and consequently nfs and lockd) are
disabled.

Original introduction from Willy:

   I've been promising to do this for about seven years now.

   It seems to work well enough, but I haven't run any serious stress
   tests on it.  This implementation uses one spinlock to protect both lock
   lists and all the i_flock chains.  It doesn't seem worth splitting up
   the locking any further.

   I had to move one memory allocation out from under the file_lock_lock.
   I hope I got that logic right.  I'm rather tempted to split out the
   find_conflict algorithm from that function into something that can be
   called separately for the FL_ACCESS case.

   I also have to drop and reacquire the file_lock_lock around the call
   to cond_resched().  This was done automatically for us before by the
   special BKL semantics.

   I had to change vfs_setlease() as it relied on the special BKL ability
   to recursively acquire the same lock.  The internal caller now calls
   __vfs_setlease and the exported interface acquires and releases the
   file_lock_lock around calling __vfs_setlease.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
---
 fs/Kconfig |    4 ++
 fs/locks.c |  116 +++++++++++++++++++++++++++++++++++++-----------------------
 2 files changed, 76 insertions(+), 44 deletions(-)

diff --git a/fs/Kconfig b/fs/Kconfig
index 5f85b59..a624d92 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -55,6 +55,10 @@ config FILE_LOCKING
           for filesystems like NFS and for the flock() system
           call. Disabling this option saves about 11k.
 
+config FLOCKS_SPINLOCK
+	bool
+	default FILE_LOCKING && !LOCK_KERNEL
+
 source "fs/notify/Kconfig"
 
 source "fs/quota/Kconfig"
diff --git a/fs/locks.c b/fs/locks.c
index ab24d49..77c3f00 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -140,9 +140,29 @@ int lease_break_time = 45;
 #define for_each_lock(inode, lockp) \
 	for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
 
+/*
+ * Protects the two list heads below, plus the inode->i_flock list
+ */
 static LIST_HEAD(file_lock_list);
 static LIST_HEAD(blocked_list);
 
+#ifdef CONFIG_FLOCKS_SPINLOCK
+static DEFINE_SPINLOCK(file_lock_lock);
+
+static inline void lock_flocks(void)
+{
+	spin_lock(&file_lock_lock);
+}
+
+static inline void unlock_flocks(void)
+{
+	spin_unlock(&file_lock_lock);
+}
+#else
+#define lock_flocks() lock_kernel()
+#define unlock_flocks() unlock_kernel()
+#endif
+
 static struct kmem_cache *filelock_cache __read_mostly;
 
 /* Allocate an empty lock structure. */
@@ -511,9 +531,9 @@ static void __locks_delete_block(struct file_lock *waiter)
  */
 static void locks_delete_block(struct file_lock *waiter)
 {
-	lock_kernel();
+	lock_flocks();
 	__locks_delete_block(waiter);
-	unlock_kernel();
+	unlock_flocks();
 }
 
 /* Insert waiter into blocker's block list.
@@ -644,7 +664,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
 {
 	struct file_lock *cfl;
 
-	lock_kernel();
+	lock_flocks();
 	for (cfl = filp->f_path.dentry->d_inode->i_flock; cfl; cfl = cfl->fl_next) {
 		if (!IS_POSIX(cfl))
 			continue;
@@ -657,7 +677,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
 			fl->fl_pid = pid_vnr(cfl->fl_nspid);
 	} else
 		fl->fl_type = F_UNLCK;
-	unlock_kernel();
+	unlock_flocks();
 	return;
 }
 EXPORT_SYMBOL(posix_test_lock);
@@ -730,18 +750,16 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
 	int error = 0;
 	int found = 0;
 
-	lock_kernel();
-	if (request->fl_flags & FL_ACCESS)
-		goto find_conflict;
-
-	if (request->fl_type != F_UNLCK) {
-		error = -ENOMEM;
+	if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
 		new_fl = locks_alloc_lock();
-		if (new_fl == NULL)
-			goto out;
-		error = 0;
+		if (!new_fl)
+			return -ENOMEM;
 	}
 
+	lock_flocks();
+	if (request->fl_flags & FL_ACCESS)
+		goto find_conflict;
+
 	for_each_lock(inode, before) {
 		struct file_lock *fl = *before;
 		if (IS_POSIX(fl))
@@ -767,8 +785,11 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
 	 * If a higher-priority process was blocked on the old file lock,
 	 * give it the opportunity to lock the file.
 	 */
-	if (found)
+	if (found) {
+		unlock_flocks();
 		cond_resched();
+		lock_flocks();
+	}
 
 find_conflict:
 	for_each_lock(inode, before) {
@@ -794,7 +815,7 @@ find_conflict:
 	error = 0;
 
 out:
-	unlock_kernel();
+	unlock_flocks();
 	if (new_fl)
 		locks_free_lock(new_fl);
 	return error;
@@ -823,7 +844,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
 		new_fl2 = locks_alloc_lock();
 	}
 
-	lock_kernel();
+	lock_flocks();
 	if (request->fl_type != F_UNLCK) {
 		for_each_lock(inode, before) {
 			fl = *before;
@@ -991,7 +1012,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
 		locks_wake_up_blocks(left);
 	}
  out:
-	unlock_kernel();
+	unlock_flocks();
 	/*
 	 * Free any unused locks.
 	 */
@@ -1066,14 +1087,14 @@ int locks_mandatory_locked(struct inode *inode)
 	/*
 	 * Search the lock list for this inode for any POSIX locks.
 	 */
-	lock_kernel();
+	lock_flocks();
 	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
 		if (!IS_POSIX(fl))
 			continue;
 		if (fl->fl_owner != owner)
 			break;
 	}
-	unlock_kernel();
+	unlock_flocks();
 	return fl ? -EAGAIN : 0;
 }
 
@@ -1186,7 +1207,7 @@ int __break_lease(struct inode *inode, unsigned int mode)
 
 	new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
 
-	lock_kernel();
+	lock_flocks();
 
 	time_out_leases(inode);
 
@@ -1247,8 +1268,10 @@ restart:
 			break_time++;
 	}
 	locks_insert_block(flock, new_fl);
+	unlock_flocks();
 	error = wait_event_interruptible_timeout(new_fl->fl_wait,
 						!new_fl->fl_next, break_time);
+	lock_flocks();
 	__locks_delete_block(new_fl);
 	if (error >= 0) {
 		if (error == 0)
@@ -1263,7 +1286,7 @@ restart:
 	}
 
 out:
-	unlock_kernel();
+	unlock_flocks();
 	if (!IS_ERR(new_fl))
 		locks_free_lock(new_fl);
 	return error;
@@ -1319,7 +1342,7 @@ int fcntl_getlease(struct file *filp)
 	struct file_lock *fl;
 	int type = F_UNLCK;
 
-	lock_kernel();
+	lock_flocks();
 	time_out_leases(filp->f_path.dentry->d_inode);
 	for (fl = filp->f_path.dentry->d_inode->i_flock; fl && IS_LEASE(fl);
 			fl = fl->fl_next) {
@@ -1328,7 +1351,7 @@ int fcntl_getlease(struct file *filp)
 			break;
 		}
 	}
-	unlock_kernel();
+	unlock_flocks();
 	return type;
 }
 
@@ -1341,7 +1364,7 @@ int fcntl_getlease(struct file *filp)
  *	The (input) flp->fl_lmops->fl_break function is required
  *	by break_lease().
  *
- *	Called with kernel lock held.
+ *	Called with file_lock_lock held.
  */
 int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
 {
@@ -1436,7 +1459,15 @@ out:
 }
 EXPORT_SYMBOL(generic_setlease);
 
- /**
+static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
+{
+	if (filp->f_op && filp->f_op->setlease)
+		return filp->f_op->setlease(filp, arg, lease);
+	else
+		return generic_setlease(filp, arg, lease);
+}
+
+/**
  *	vfs_setlease        -       sets a lease on an open file
  *	@filp: file pointer
  *	@arg: type of lease to obtain
@@ -1467,12 +1498,9 @@ int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
 {
 	int error;
 
-	lock_kernel();
-	if (filp->f_op && filp->f_op->setlease)
-		error = filp->f_op->setlease(filp, arg, lease);
-	else
-		error = generic_setlease(filp, arg, lease);
-	unlock_kernel();
+	lock_flocks();
+	error = __vfs_setlease(filp, arg, lease);
+	unlock_flocks();
 
 	return error;
 }
@@ -1499,9 +1527,9 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
 	if (error)
 		return error;
 
-	lock_kernel();
+	lock_flocks();
 
-	error = vfs_setlease(filp, arg, &flp);
+	error = __vfs_setlease(filp, arg, &flp);
 	if (error || arg == F_UNLCK)
 		goto out_unlock;
 
@@ -1516,7 +1544,7 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
 
 	error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
 out_unlock:
-	unlock_kernel();
+	unlock_flocks();
 	return error;
 }
 
@@ -2020,7 +2048,7 @@ void locks_remove_flock(struct file *filp)
 			fl.fl_ops->fl_release_private(&fl);
 	}
 
-	lock_kernel();
+	lock_flocks();
 	before = &inode->i_flock;
 
 	while ((fl = *before) != NULL) {
@@ -2038,7 +2066,7 @@ void locks_remove_flock(struct file *filp)
  		}
 		before = &fl->fl_next;
 	}
-	unlock_kernel();
+	unlock_flocks();
 }
 
 /**
@@ -2053,12 +2081,12 @@ posix_unblock_lock(struct file *filp, struct file_lock *waiter)
 {
 	int status = 0;
 
-	lock_kernel();
+	lock_flocks();
 	if (waiter->fl_next)
 		__locks_delete_block(waiter);
 	else
 		status = -ENOENT;
-	unlock_kernel();
+	unlock_flocks();
 	return status;
 }
 
@@ -2172,7 +2200,7 @@ static int locks_show(struct seq_file *f, void *v)
 
 static void *locks_start(struct seq_file *f, loff_t *pos)
 {
-	lock_kernel();
+	lock_flocks();
 	f->private = (void *)1;
 	return seq_list_start(&file_lock_list, *pos);
 }
@@ -2184,7 +2212,7 @@ static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
 
 static void locks_stop(struct seq_file *f, void *v)
 {
-	unlock_kernel();
+	unlock_flocks();
 }
 
 static const struct seq_operations locks_seq_operations = {
@@ -2231,7 +2259,7 @@ int lock_may_read(struct inode *inode, loff_t start, unsigned long len)
 {
 	struct file_lock *fl;
 	int result = 1;
-	lock_kernel();
+	lock_flocks();
 	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
 		if (IS_POSIX(fl)) {
 			if (fl->fl_type == F_RDLCK)
@@ -2248,7 +2276,7 @@ int lock_may_read(struct inode *inode, loff_t start, unsigned long len)
 		result = 0;
 		break;
 	}
-	unlock_kernel();
+	unlock_flocks();
 	return result;
 }
 
@@ -2271,7 +2299,7 @@ int lock_may_write(struct inode *inode, loff_t start, unsigned long len)
 {
 	struct file_lock *fl;
 	int result = 1;
-	lock_kernel();
+	lock_flocks();
 	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
 		if (IS_POSIX(fl)) {
 			if ((fl->fl_end < start) || (fl->fl_start > (start + len)))
@@ -2286,7 +2314,7 @@ int lock_may_write(struct inode *inode, loff_t start, unsigned long len)
 		result = 0;
 		break;
 	}
-	unlock_kernel();
+	unlock_flocks();
 	return result;
 }
 
-- 
1.7.1

[PATCH 3/3] sound: push BKL into open functions

[Arnd Bergmann]

This moves the lock_kernel() call from soundcore_open
to the individual OSS device drivers, where we can deal
with it one driver at a time if needed, or just kill
off the drivers.

All core components in ALSA already provide
adequate locking in their open()-functions
and do not require the big kernel lock, so
there is no need to add the BKL there.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: alsa-devel@alsa-project.org
---
 arch/um/drivers/hostaudio_kern.c   |    6 ++++++
 sound/core/hwdep.c                 |   14 ++++++++++----
 sound/core/oss/mixer_oss.c         |   19 +++++++++++--------
 sound/oss/au1550_ac97.c            |   26 +++++++++++++++++---------
 sound/oss/dmasound/dmasound_core.c |   28 ++++++++++++++++++++++------
 sound/oss/msnd_pinnacle.c          |   10 +++++++---
 sound/oss/sh_dac_audio.c           |    9 +++++++--
 sound/oss/soundcard.c              |   20 +++++++++++---------
 sound/oss/swarm_cs4297a.c          |   17 ++++++++++++++++-
 sound/oss/vwsnd.c                  |    8 ++++++++
 sound/sound_core.c                 |    6 +-----
 11 files changed, 116 insertions(+), 47 deletions(-)

diff --git a/arch/um/drivers/hostaudio_kern.c b/arch/um/drivers/hostaudio_kern.c
index ae42695..68142df 100644
--- a/arch/um/drivers/hostaudio_kern.c
+++ b/arch/um/drivers/hostaudio_kern.c
@@ -8,6 +8,7 @@
 #include "linux/slab.h"
 #include "linux/sound.h"
 #include "linux/soundcard.h"
+#include "linux/smp_lock.h"
 #include "asm/uaccess.h"
 #include "init.h"
 #include "os.h"
@@ -198,7 +199,10 @@ static int hostaudio_open(struct inode *inode, struct file *file)
 	if (file->f_mode & FMODE_WRITE)
 		w = 1;
 
+	lock_kernel();
 	ret = os_open_file(dsp, of_set_rw(OPENFLAGS(), r, w), 0);
+	unlock_kernel();
+
 	if (ret < 0) {
 		kfree(state);
 		return ret;
@@ -254,7 +258,9 @@ static int hostmixer_open_mixdev(struct inode *inode, struct file *file)
 	if (file->f_mode & FMODE_WRITE)
 		w = 1;
 
+	lock_kernel();
 	ret = os_open_file(mixer, of_set_rw(OPENFLAGS(), r, w), 0);
+	unlock_kernel();
 
 	if (ret < 0) {
 		printk(KERN_ERR "hostaudio_open_mixdev failed to open '%s', "
diff --git a/sound/core/hwdep.c b/sound/core/hwdep.c
index a70ee7f..3439587 100644
--- a/sound/core/hwdep.c
+++ b/sound/core/hwdep.c
@@ -94,13 +94,18 @@ static int snd_hwdep_open(struct inode *inode, struct file * file)
 		hw = snd_lookup_oss_minor_data(iminor(inode),
 					       SNDRV_OSS_DEVICE_TYPE_DMFM);
 #endif
-	} else
-		return -ENXIO;
+	} else {
+		err = -ENXIO;
+		goto out;
+	}
+
+	err = -ENODEV;
 	if (hw == NULL)
-		return -ENODEV;
+		goto out;
 
+	err = -EFAULT;
 	if (!try_module_get(hw->card->module))
-		return -EFAULT;
+		goto out;
 
 	init_waitqueue_entry(&wait, current);
 	add_wait_queue(&hw->open_wait, &wait);
@@ -147,6 +152,7 @@ static int snd_hwdep_open(struct inode *inode, struct file * file)
 	mutex_unlock(&hw->open_mutex);
 	if (err < 0)
 		module_put(hw->card->module);
+out:
 	return err;
 }
 
diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
index f50ebf2..c30b1f3 100644
--- a/sound/core/oss/mixer_oss.c
+++ b/sound/core/oss/mixer_oss.c
@@ -49,17 +49,19 @@ static int snd_mixer_oss_open(struct inode *inode, struct file *file)
 
 	card = snd_lookup_oss_minor_data(iminor(inode),
 					 SNDRV_OSS_DEVICE_TYPE_MIXER);
-	if (card == NULL)
-		return -ENODEV;
-	if (card->mixer_oss == NULL)
-		return -ENODEV;
+	err = -ENODEV;
+	if (card == NULL || card->mixer_oss == NULL)
+		goto out;
+
 	err = snd_card_file_add(card, file);
 	if (err < 0)
-		return err;
+		goto out;
+
 	fmixer = kzalloc(sizeof(*fmixer), GFP_KERNEL);
 	if (fmixer == NULL) {
 		snd_card_file_remove(card, file);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto out;
 	}
 	fmixer->card = card;
 	fmixer->mixer = card->mixer_oss;
@@ -67,9 +69,10 @@ static int snd_mixer_oss_open(struct inode *inode, struct file *file)
 	if (!try_module_get(card->module)) {
 		kfree(fmixer);
 		snd_card_file_remove(card, file);
-		return -EFAULT;
+		err = -EFAULT;
 	}
-	return 0;
+out:
+	return err;
 }
 
 static int snd_mixer_oss_release(struct inode *inode, struct file *file)
diff --git a/sound/oss/au1550_ac97.c b/sound/oss/au1550_ac97.c
index c1070e3..47143a3 100644
--- a/sound/oss/au1550_ac97.c
+++ b/sound/oss/au1550_ac97.c
@@ -43,6 +43,7 @@
 #include <linux/sound.h>
 #include <linux/slab.h>
 #include <linux/soundcard.h>
+#include <linux/smp_lock.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -807,7 +808,9 @@ au1550_llseek(struct file *file, loff_t offset, int origin)
 static int
 au1550_open_mixdev(struct inode *inode, struct file *file)
 {
+	lock_kernel();
 	file->private_data = &au1550_state;
+	unlock_kernel();
 	return 0;
 }
 
@@ -1797,21 +1800,22 @@ au1550_open(struct inode *inode, struct file *file)
 #endif
 
 	file->private_data = s;
+	lock_kernel();
 	/* wait for device to become free */
 	mutex_lock(&s->open_mutex);
 	while (s->open_mode & file->f_mode) {
-		if (file->f_flags & O_NONBLOCK) {
-			mutex_unlock(&s->open_mutex);
-			return -EBUSY;
-		}
+		ret = -EBUSY;
+		if (file->f_flags & O_NONBLOCK)
+			goto out;		
 		add_wait_queue(&s->open_wait, &wait);
 		__set_current_state(TASK_INTERRUPTIBLE);
 		mutex_unlock(&s->open_mutex);
 		schedule();
 		remove_wait_queue(&s->open_wait, &wait);
 		set_current_state(TASK_RUNNING);
+		ret = -ERESTARTSYS;
 		if (signal_pending(current))
-			return -ERESTARTSYS;
+			goto out2;
 		mutex_lock(&s->open_mutex);
 	}
 
@@ -1840,17 +1844,21 @@ au1550_open(struct inode *inode, struct file *file)
 
 	if (file->f_mode & FMODE_READ) {
 		if ((ret = prog_dmabuf_adc(s)))
-			return ret;
+			goto out;
 	}
 	if (file->f_mode & FMODE_WRITE) {
 		if ((ret = prog_dmabuf_dac(s)))
-			return ret;
+			goto out;
 	}
 
 	s->open_mode |= file->f_mode & (FMODE_READ | FMODE_WRITE);
-	mutex_unlock(&s->open_mutex);
 	mutex_init(&s->sem);
-	return 0;
+	ret = 0;
+out:
+	mutex_unlock(&s->open_mutex);
+out2:
+	unlock_kernel();
+	return ret;
 }
 
 static int
diff --git a/sound/oss/dmasound/dmasound_core.c b/sound/oss/dmasound/dmasound_core.c
index 3f3c3f7..5a4f38c 100644
--- a/sound/oss/dmasound/dmasound_core.c
+++ b/sound/oss/dmasound/dmasound_core.c
@@ -323,9 +323,13 @@ static struct {
 
 static int mixer_open(struct inode *inode, struct file *file)
 {
-	if (!try_module_get(dmasound.mach.owner))
+	lock_kernel();
+	if (!try_module_get(dmasound.mach.owner)) {
+		unlock_kernel();
 		return -ENODEV;
+	}
 	mixer.busy = 1;
+	unlock_kernel();
 	return 0;
 }
 
@@ -737,8 +741,11 @@ static int sq_open(struct inode *inode, struct file *file)
 {
 	int rc;
 
-	if (!try_module_get(dmasound.mach.owner))
+	lock_kernel();
+	if (!try_module_get(dmasound.mach.owner)) {
+		unlock_kernel();
 		return -ENODEV;
+	}
 
 	rc = write_sq_open(file); /* checks the f_mode */
 	if (rc)
@@ -781,10 +788,11 @@ static int sq_open(struct inode *inode, struct file *file)
 		sound_set_format(AFMT_MU_LAW);
 	}
 #endif
-
+	unlock_kernel();
 	return 0;
  out:
 	module_put(dmasound.mach.owner);
+	unlock_kernel();
 	return rc;
 }
 
@@ -1226,12 +1234,17 @@ static int state_open(struct inode *inode, struct file *file)
 {
 	char *buffer = state.buf;
 	int len = 0;
+	int ret;
 
+	lock_kernel();
+	ret = -EBUSY;
 	if (state.busy)
-		return -EBUSY;
+		goto out;
 
+	ret = -ENODEV;
 	if (!try_module_get(dmasound.mach.owner))
-		return -ENODEV;
+		goto out;
+
 	state.ptr = 0;
 	state.busy = 1;
 
@@ -1293,7 +1306,10 @@ printk("dmasound: stat buffer used %d bytes\n", len) ;
 		printk(KERN_ERR "dmasound_core: stat buffer overflowed!\n");
 
 	state.len = len;
-	return 0;
+	ret = 0;
+out:
+	unlock_kernel();
+	return ret;
 }
 
 static int state_release(struct inode *inode, struct file *file)
diff --git a/sound/oss/msnd_pinnacle.c b/sound/oss/msnd_pinnacle.c
index a1e3f96..153d822 100644
--- a/sound/oss/msnd_pinnacle.c
+++ b/sound/oss/msnd_pinnacle.c
@@ -756,12 +756,15 @@ static int dev_open(struct inode *inode, struct file *file)
 	int minor = iminor(inode);
 	int err = 0;
 
+	lock_kernel();
 	if (minor == dev.dsp_minor) {
 		if ((file->f_mode & FMODE_WRITE &&
 		     test_bit(F_AUDIO_WRITE_INUSE, &dev.flags)) ||
 		    (file->f_mode & FMODE_READ &&
-		     test_bit(F_AUDIO_READ_INUSE, &dev.flags)))
-			return -EBUSY;
+		     test_bit(F_AUDIO_READ_INUSE, &dev.flags))) {
+			err = -EBUSY;
+			goto out;
+		}
 
 		if ((err = dsp_open(file)) >= 0) {
 			dev.nresets = 0;
@@ -782,7 +785,8 @@ static int dev_open(struct inode *inode, struct file *file)
 		/* nothing */
 	} else
 		err = -EINVAL;
-
+out:
+	unlock_kernel();
 	return err;
 }
 
diff --git a/sound/oss/sh_dac_audio.c b/sound/oss/sh_dac_audio.c
index 4153752..8f0be40 100644
--- a/sound/oss/sh_dac_audio.c
+++ b/sound/oss/sh_dac_audio.c
@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/sound.h>
+#include <linux/smp_lock.h>
 #include <linux/soundcard.h>
 #include <linux/interrupt.h>
 #include <linux/hrtimer.h>
@@ -216,13 +217,17 @@ static int dac_audio_open(struct inode *inode, struct file *file)
 {
 	if (file->f_mode & FMODE_READ)
 		return -ENODEV;
-	if (in_use)
+
+	lock_kernel();
+	if (in_use) {
+		unlock_kernel();
 		return -EBUSY;
+	}
 
 	in_use = 1;
 
 	dac_audio_start();
-
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/sound/oss/soundcard.c b/sound/oss/soundcard.c
index 2d9c513..92aa762 100644
--- a/sound/oss/soundcard.c
+++ b/sound/oss/soundcard.c
@@ -210,42 +210,44 @@ static int sound_open(struct inode *inode, struct file *file)
 		printk(KERN_ERR "Invalid minor device %d\n", dev);
 		return -ENXIO;
 	}
+	lock_kernel();
 	switch (dev & 0x0f) {
 	case SND_DEV_CTL:
 		dev >>= 4;
 		if (dev >= 0 && dev < MAX_MIXER_DEV && mixer_devs[dev] == NULL) {
 			request_module("mixer%d", dev);
 		}
+		retval = -ENXIO;
 		if (dev && (dev >= num_mixers || mixer_devs[dev] == NULL))
-			return -ENXIO;
+			break;
 	
 		if (!try_module_get(mixer_devs[dev]->owner))
-			return -ENXIO;
+			break;
+
+		retval = 0;
 		break;
 
 	case SND_DEV_SEQ:
 	case SND_DEV_SEQ2:
-		if ((retval = sequencer_open(dev, file)) < 0)
-			return retval;
+		retval = sequencer_open(dev, file);
 		break;
 
 	case SND_DEV_MIDIN:
-		if ((retval = MIDIbuf_open(dev, file)) < 0)
-			return retval;
+		retval = MIDIbuf_open(dev, file);
 		break;
 
 	case SND_DEV_DSP:
 	case SND_DEV_DSP16:
 	case SND_DEV_AUDIO:
-		if ((retval = audio_open(dev, file)) < 0)
-			return retval;
+		retval = audio_open(dev, file);
 		break;
 
 	default:
 		printk(KERN_ERR "Invalid minor device %d\n", dev);
-		return -ENXIO;
+		retval = -ENXIO;
 	}
 
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/sound/oss/swarm_cs4297a.c b/sound/oss/swarm_cs4297a.c
index 3136c88..34b0838 100644
--- a/sound/oss/swarm_cs4297a.c
+++ b/sound/oss/swarm_cs4297a.c
@@ -68,6 +68,7 @@
 #include <linux/delay.h>
 #include <linux/sound.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <linux/soundcard.h>
 #include <linux/ac97_codec.h>
 #include <linux/pci.h>
@@ -1534,6 +1535,7 @@ static int cs4297a_open_mixdev(struct inode *inode, struct file *file)
 	CS_DBGOUT(CS_FUNCTION | CS_OPEN, 4,
 		  printk(KERN_INFO "cs4297a: cs4297a_open_mixdev()+\n"));
 
+	lock_kernel();
 	list_for_each(entry, &cs4297a_devs)
 	{
 		s = list_entry(entry, struct cs4297a_state, list);
@@ -1544,6 +1546,8 @@ static int cs4297a_open_mixdev(struct inode *inode, struct file *file)
 	{
 		CS_DBGOUT(CS_FUNCTION | CS_OPEN | CS_ERROR, 2,
 			printk(KERN_INFO "cs4297a: cs4297a_open_mixdev()- -ENODEV\n"));
+
+		unlock_kernel();
 		return -ENODEV;
 	}
 	VALIDATE_STATE(s);
@@ -1551,6 +1555,7 @@ static int cs4297a_open_mixdev(struct inode *inode, struct file *file)
 
 	CS_DBGOUT(CS_FUNCTION | CS_OPEN, 4,
 		  printk(KERN_INFO "cs4297a: cs4297a_open_mixdev()- 0\n"));
+	unlock_kernel();
 
 	return nonseekable_open(inode, file);
 }
@@ -2369,7 +2374,7 @@ static int cs4297a_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static int cs4297a_open(struct inode *inode, struct file *file)
+static int cs4297a_locked_open(struct inode *inode, struct file *file)
 {
 	int minor = iminor(inode);
 	struct cs4297a_state *s=NULL;
@@ -2486,6 +2491,16 @@ static int cs4297a_open(struct inode *inode, struct file *file)
 	return nonseekable_open(inode, file);
 }
 
+static int cs4297a_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	lock_kernel();
+	ret = cs4297a_open(inode, file);
+	unlock_kernel();
+
+	return ret;
+}
 
 // ******************************************************************************************
 //   Wave (audio) file operations struct.
diff --git a/sound/oss/vwsnd.c b/sound/oss/vwsnd.c
index 20b3b32..99c94c4 100644
--- a/sound/oss/vwsnd.c
+++ b/sound/oss/vwsnd.c
@@ -2921,6 +2921,7 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
 
 	DBGE("(inode=0x%p, file=0x%p)\n", inode, file);
 
+	lock_kernel();
 	INC_USE_COUNT;
 	for (devc = vwsnd_dev_list; devc; devc = devc->next_dev)
 		if ((devc->audio_minor & ~0x0F) == (minor & ~0x0F))
@@ -2928,6 +2929,7 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
 
 	if (devc == NULL) {
 		DEC_USE_COUNT;
+		unlock_kernel();
 		return -ENODEV;
 	}
 
@@ -2936,11 +2938,13 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
 		mutex_unlock(&devc->open_mutex);
 		if (file->f_flags & O_NONBLOCK) {
 			DEC_USE_COUNT;
+			unlock_kernel();
 			return -EBUSY;
 		}
 		interruptible_sleep_on(&devc->open_wait);
 		if (signal_pending(current)) {
 			DEC_USE_COUNT;
+			unlock_kernel();
 			return -ERESTARTSYS;
 		}
 		mutex_lock(&devc->open_mutex);
@@ -2993,6 +2997,7 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
 
 	file->private_data = devc;
 	DBGRV();
+	unlock_kernel();
 	return 0;
 }
 
@@ -3062,15 +3067,18 @@ static int vwsnd_mixer_open(struct inode *inode, struct file *file)
 	DBGEV("(inode=0x%p, file=0x%p)\n", inode, file);
 
 	INC_USE_COUNT;
+	lock_kernel();
 	for (devc = vwsnd_dev_list; devc; devc = devc->next_dev)
 		if (devc->mixer_minor == iminor(inode))
 			break;
 
 	if (devc == NULL) {
 		DEC_USE_COUNT;
+		unlock_kernel();
 		return -ENODEV;
 	}
 	file->private_data = devc;
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/sound/sound_core.c b/sound/sound_core.c
index c8627fc..cb61317 100644
--- a/sound/sound_core.c
+++ b/sound/sound_core.c
@@ -629,12 +629,8 @@ static int soundcore_open(struct inode *inode, struct file *file)
 		file->f_op = new_fops;
 		spin_unlock(&sound_loader_lock);
 
-		if (file->f_op->open) {
-			/* TODO: push down BKL into indivial open functions */
-			lock_kernel();
+		if (file->f_op->open)
 			err = file->f_op->open(inode,file);
-			unlock_kernel();
-		}
 
 		if (err) {
 			fops_put(file->f_op);
-- 
1.7.1

Re: [PATCH 2/3] Remove BKL from fs/locks.c

[Christoph Hellwig]

On Sat, Jul 10, 2010 at 11:51:40PM +0200, Arnd Bergmann wrote:
> From: Matthew Wilcox <willy@linux.intel.com>
> 
> I've taken a patch originally written by Matthew Wilcox and
> ported it to the current version. Unfortunately, the change
> conflicts with the use of lockd, which still heavily uses
> the big kernel lock.
> 
> As a workaround, I've made the behaviour configurable,
> it either uses the BKL when it's enabled or a spinlock
> when the BKL (and consequently nfs and lockd) are
> disabled.

Defintively not something we want in mainline.  But keep poking
the nfs guys to sort the lockd mess out for real.

Re: [PATCH 3/3] sound: push BKL into open functions

[Jaroslav Kysela]

On Sat, 10 Jul 2010, Arnd Bergmann wrote:

> --- a/sound/core/hwdep.c
> +++ b/sound/core/hwdep.c
> @@ -94,13 +94,18 @@ static int snd_hwdep_open(struct inode *inode, struct file * file)
> 		hw = snd_lookup_oss_minor_data(iminor(inode),
> 					       SNDRV_OSS_DEVICE_TYPE_DMFM);
> #endif
> -	} else
> -		return -ENXIO;
> +	} else {
> +		err = -ENXIO;
> +		goto out;
> +	}
> +
> +	err = -ENODEV;
> 	if (hw == NULL)
> -		return -ENODEV;
> +		goto out;
>
> +	err = -EFAULT;
> 	if (!try_module_get(hw->card->module))
> -		return -EFAULT;
> +		goto out;
>
> 	init_waitqueue_entry(&wait, current);
> 	add_wait_queue(&hw->open_wait, &wait);
> @@ -147,6 +152,7 @@ static int snd_hwdep_open(struct inode *inode, struct file * file)
> 	mutex_unlock(&hw->open_mutex);
> 	if (err < 0)
> 		module_put(hw->card->module);
> +out:
> 	return err;
> }
>
> diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
> index f50ebf2..c30b1f3 100644
> --- a/sound/core/oss/mixer_oss.c
> +++ b/sound/core/oss/mixer_oss.c
> @@ -49,17 +49,19 @@ static int snd_mixer_oss_open(struct inode *inode, struct file *file)
>
> 	card = snd_lookup_oss_minor_data(iminor(inode),
> 					 SNDRV_OSS_DEVICE_TYPE_MIXER);
> -	if (card == NULL)
> -		return -ENODEV;
> -	if (card->mixer_oss == NULL)
> -		return -ENODEV;
> +	err = -ENODEV;
> +	if (card == NULL || card->mixer_oss == NULL)
> +		goto out;
> +
> 	err = snd_card_file_add(card, file);
> 	if (err < 0)
> -		return err;
> +		goto out;
> +
> 	fmixer = kzalloc(sizeof(*fmixer), GFP_KERNEL);
> 	if (fmixer == NULL) {
> 		snd_card_file_remove(card, file);
> -		return -ENOMEM;
> +		err = -ENOMEM;
> +		goto out;
> 	}
> 	fmixer->card = card;
> 	fmixer->mixer = card->mixer_oss;
> @@ -67,9 +69,10 @@ static int snd_mixer_oss_open(struct inode *inode, struct file *file)
> 	if (!try_module_get(card->module)) {
> 		kfree(fmixer);
> 		snd_card_file_remove(card, file);
> -		return -EFAULT;
> +		err = -EFAULT;
> 	}
> -	return 0;
> +out:
> +	return err;
> }
>

I don't see any reason (benefit) to add gotos to these two functions.

 						Jaroslav

-----
Jaroslav Kysela <perex@perex.cz>
Linux Kernel Sound Maintainer
ALSA Project; Red Hat, Inc.

Re: [PATCH 3/3] sound: push BKL into open functions

[Jaroslav Kysela]

On Sat, 10 Jul 2010, Arnd Bergmann wrote:

> --- a/sound/core/hwdep.c
> +++ b/sound/core/hwdep.c
> @@ -94,13 +94,18 @@ static int snd_hwdep_open(struct inode *inode, struct file * file)
> 		hw = snd_lookup_oss_minor_data(iminor(inode),
> 					       SNDRV_OSS_DEVICE_TYPE_DMFM);
> #endif
> -	} else
> -		return -ENXIO;
> +	} else {
> +		err = -ENXIO;
> +		goto out;
> +	}
> +
> +	err = -ENODEV;
> 	if (hw == NULL)
> -		return -ENODEV;
> +		goto out;
>
> +	err = -EFAULT;
> 	if (!try_module_get(hw->card->module))
> -		return -EFAULT;
> +		goto out;
>
> 	init_waitqueue_entry(&wait, current);
> 	add_wait_queue(&hw->open_wait, &wait);
> @@ -147,6 +152,7 @@ static int snd_hwdep_open(struct inode *inode, struct file * file)
> 	mutex_unlock(&hw->open_mutex);
> 	if (err < 0)
> 		module_put(hw->card->module);
> +out:
> 	return err;
> }
>
> diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
> index f50ebf2..c30b1f3 100644
> --- a/sound/core/oss/mixer_oss.c
> +++ b/sound/core/oss/mixer_oss.c
> @@ -49,17 +49,19 @@ static int snd_mixer_oss_open(struct inode *inode, struct file *file)
>
> 	card = snd_lookup_oss_minor_data(iminor(inode),
> 					 SNDRV_OSS_DEVICE_TYPE_MIXER);
> -	if (card == NULL)
> -		return -ENODEV;
> -	if (card->mixer_oss == NULL)
> -		return -ENODEV;
> +	err = -ENODEV;
> +	if (card == NULL || card->mixer_oss == NULL)
> +		goto out;
> +
> 	err = snd_card_file_add(card, file);
> 	if (err < 0)
> -		return err;
> +		goto out;
> +
> 	fmixer = kzalloc(sizeof(*fmixer), GFP_KERNEL);
> 	if (fmixer == NULL) {
> 		snd_card_file_remove(card, file);
> -		return -ENOMEM;
> +		err = -ENOMEM;
> +		goto out;
> 	}
> 	fmixer->card = card;
> 	fmixer->mixer = card->mixer_oss;
> @@ -67,9 +69,10 @@ static int snd_mixer_oss_open(struct inode *inode, struct file *file)
> 	if (!try_module_get(card->module)) {
> 		kfree(fmixer);
> 		snd_card_file_remove(card, file);
> -		return -EFAULT;
> +		err = -EFAULT;
> 	}
> -	return 0;
> +out:
> +	return err;
> }
>

I don't see any reason (benefit) to add gotos to these two functions.

 						Jaroslav

-----
Jaroslav Kysela <perex@perex.cz>
Linux Kernel Sound Maintainer
ALSA Project; Red Hat, Inc.

Re: [PATCH 3/3] sound: push BKL into open functions

[Arnd Bergmann]

This moves the lock_kernel() call from soundcore_open
to the individual OSS device drivers, where we can deal
with it one driver at a time if needed, or just kill
off the drivers.

All core components in ALSA already provide
adequate locking in their open()-functions
and do not require the big kernel lock, so
there is no need to add the BKL there.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
On Sunday 11 July 2010 09:15:22 Jaroslav Kysela wrote:
> I don't see any reason (benefit) to add gotos to these two functions.
> 
Sorry, I had removed them and then forgot the git-add before
creating the emails. Originally, I had two patches, one for
pushing down the BKL into every sound driver (hence the goto)
and a second patch to remove the BKL again from all the native
alsa drivers. If you prefer, I can also give you the separate
patches, but I figured that since none of the ALSA drivers needs
the BKL, the combined patch would be better.

This is the corrected combined version.

	Arnd

 arch/um/drivers/hostaudio_kern.c   |    6 ++++++
 sound/oss/au1550_ac97.c            |   26 +++++++++++++++++---------
 sound/oss/dmasound/dmasound_core.c |   28 ++++++++++++++++++++++------
 sound/oss/msnd_pinnacle.c          |   10 +++++++---
 sound/oss/sh_dac_audio.c           |    9 +++++++--
 sound/oss/soundcard.c              |   20 +++++++++++---------
 sound/oss/swarm_cs4297a.c          |   17 ++++++++++++++++-
 sound/oss/vwsnd.c                  |    8 ++++++++
 sound/sound_core.c                 |    6 +-----
 9 files changed, 95 insertions(+), 35 deletions(-)

diff --git a/arch/um/drivers/hostaudio_kern.c b/arch/um/drivers/hostaudio_kern.c
index ae42695..68142df 100644
--- a/arch/um/drivers/hostaudio_kern.c
+++ b/arch/um/drivers/hostaudio_kern.c
@@ -8,6 +8,7 @@
 #include "linux/slab.h"
 #include "linux/sound.h"
 #include "linux/soundcard.h"
+#include "linux/smp_lock.h"
 #include "asm/uaccess.h"
 #include "init.h"
 #include "os.h"
@@ -198,7 +199,10 @@ static int hostaudio_open(struct inode *inode, struct file *file)
 	if (file->f_mode & FMODE_WRITE)
 		w = 1;
 
+	lock_kernel();
 	ret = os_open_file(dsp, of_set_rw(OPENFLAGS(), r, w), 0);
+	unlock_kernel();
+
 	if (ret < 0) {
 		kfree(state);
 		return ret;
@@ -254,7 +258,9 @@ static int hostmixer_open_mixdev(struct inode *inode, struct file *file)
 	if (file->f_mode & FMODE_WRITE)
 		w = 1;
 
+	lock_kernel();
 	ret = os_open_file(mixer, of_set_rw(OPENFLAGS(), r, w), 0);
+	unlock_kernel();
 
 	if (ret < 0) {
 		printk(KERN_ERR "hostaudio_open_mixdev failed to open '%s', "
diff --git a/sound/oss/au1550_ac97.c b/sound/oss/au1550_ac97.c
index c1070e3..47143a3 100644
--- a/sound/oss/au1550_ac97.c
+++ b/sound/oss/au1550_ac97.c
@@ -43,6 +43,7 @@
 #include <linux/sound.h>
 #include <linux/slab.h>
 #include <linux/soundcard.h>
+#include <linux/smp_lock.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -807,7 +808,9 @@ au1550_llseek(struct file *file, loff_t offset, int origin)
 static int
 au1550_open_mixdev(struct inode *inode, struct file *file)
 {
+	lock_kernel();
 	file->private_data = &au1550_state;
+	unlock_kernel();
 	return 0;
 }
 
@@ -1797,21 +1800,22 @@ au1550_open(struct inode *inode, struct file *file)
 #endif
 
 	file->private_data = s;
+	lock_kernel();
 	/* wait for device to become free */
 	mutex_lock(&s->open_mutex);
 	while (s->open_mode & file->f_mode) {
-		if (file->f_flags & O_NONBLOCK) {
-			mutex_unlock(&s->open_mutex);
-			return -EBUSY;
-		}
+		ret = -EBUSY;
+		if (file->f_flags & O_NONBLOCK)
+			goto out;		
 		add_wait_queue(&s->open_wait, &wait);
 		__set_current_state(TASK_INTERRUPTIBLE);
 		mutex_unlock(&s->open_mutex);
 		schedule();
 		remove_wait_queue(&s->open_wait, &wait);
 		set_current_state(TASK_RUNNING);
+		ret = -ERESTARTSYS;
 		if (signal_pending(current))
-			return -ERESTARTSYS;
+			goto out2;
 		mutex_lock(&s->open_mutex);
 	}
 
@@ -1840,17 +1844,21 @@ au1550_open(struct inode *inode, struct file *file)
 
 	if (file->f_mode & FMODE_READ) {
 		if ((ret = prog_dmabuf_adc(s)))
-			return ret;
+			goto out;
 	}
 	if (file->f_mode & FMODE_WRITE) {
 		if ((ret = prog_dmabuf_dac(s)))
-			return ret;
+			goto out;
 	}
 
 	s->open_mode |= file->f_mode & (FMODE_READ | FMODE_WRITE);
-	mutex_unlock(&s->open_mutex);
 	mutex_init(&s->sem);
-	return 0;
+	ret = 0;
+out:
+	mutex_unlock(&s->open_mutex);
+out2:
+	unlock_kernel();
+	return ret;
 }
 
 static int
diff --git a/sound/oss/dmasound/dmasound_core.c b/sound/oss/dmasound/dmasound_core.c
index 3f3c3f7..5a4f38c 100644
--- a/sound/oss/dmasound/dmasound_core.c
+++ b/sound/oss/dmasound/dmasound_core.c
@@ -323,9 +323,13 @@ static struct {
 
 static int mixer_open(struct inode *inode, struct file *file)
 {
-	if (!try_module_get(dmasound.mach.owner))
+	lock_kernel();
+	if (!try_module_get(dmasound.mach.owner)) {
+		unlock_kernel();
 		return -ENODEV;
+	}
 	mixer.busy = 1;
+	unlock_kernel();
 	return 0;
 }
 
@@ -737,8 +741,11 @@ static int sq_open(struct inode *inode, struct file *file)
 {
 	int rc;
 
-	if (!try_module_get(dmasound.mach.owner))
+	lock_kernel();
+	if (!try_module_get(dmasound.mach.owner)) {
+		unlock_kernel();
 		return -ENODEV;
+	}
 
 	rc = write_sq_open(file); /* checks the f_mode */
 	if (rc)
@@ -781,10 +788,11 @@ static int sq_open(struct inode *inode, struct file *file)
 		sound_set_format(AFMT_MU_LAW);
 	}
 #endif
-
+	unlock_kernel();
 	return 0;
  out:
 	module_put(dmasound.mach.owner);
+	unlock_kernel();
 	return rc;
 }
 
@@ -1226,12 +1234,17 @@ static int state_open(struct inode *inode, struct file *file)
 {
 	char *buffer = state.buf;
 	int len = 0;
+	int ret;
 
+	lock_kernel();
+	ret = -EBUSY;
 	if (state.busy)
-		return -EBUSY;
+		goto out;
 
+	ret = -ENODEV;
 	if (!try_module_get(dmasound.mach.owner))
-		return -ENODEV;
+		goto out;
+
 	state.ptr = 0;
 	state.busy = 1;
 
@@ -1293,7 +1306,10 @@ printk("dmasound: stat buffer used %d bytes\n", len) ;
 		printk(KERN_ERR "dmasound_core: stat buffer overflowed!\n");
 
 	state.len = len;
-	return 0;
+	ret = 0;
+out:
+	unlock_kernel();
+	return ret;
 }
 
 static int state_release(struct inode *inode, struct file *file)
diff --git a/sound/oss/msnd_pinnacle.c b/sound/oss/msnd_pinnacle.c
index a1e3f96..153d822 100644
--- a/sound/oss/msnd_pinnacle.c
+++ b/sound/oss/msnd_pinnacle.c
@@ -756,12 +756,15 @@ static int dev_open(struct inode *inode, struct file *file)
 	int minor = iminor(inode);
 	int err = 0;
 
+	lock_kernel();
 	if (minor == dev.dsp_minor) {
 		if ((file->f_mode & FMODE_WRITE &&
 		     test_bit(F_AUDIO_WRITE_INUSE, &dev.flags)) ||
 		    (file->f_mode & FMODE_READ &&
-		     test_bit(F_AUDIO_READ_INUSE, &dev.flags)))
-			return -EBUSY;
+		     test_bit(F_AUDIO_READ_INUSE, &dev.flags))) {
+			err = -EBUSY;
+			goto out;
+		}
 
 		if ((err = dsp_open(file)) >= 0) {
 			dev.nresets = 0;
@@ -782,7 +785,8 @@ static int dev_open(struct inode *inode, struct file *file)
 		/* nothing */
 	} else
 		err = -EINVAL;
-
+out:
+	unlock_kernel();
 	return err;
 }
 
diff --git a/sound/oss/sh_dac_audio.c b/sound/oss/sh_dac_audio.c
index 4153752..8f0be40 100644
--- a/sound/oss/sh_dac_audio.c
+++ b/sound/oss/sh_dac_audio.c
@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/sound.h>
+#include <linux/smp_lock.h>
 #include <linux/soundcard.h>
 #include <linux/interrupt.h>
 #include <linux/hrtimer.h>
@@ -216,13 +217,17 @@ static int dac_audio_open(struct inode *inode, struct file *file)
 {
 	if (file->f_mode & FMODE_READ)
 		return -ENODEV;
-	if (in_use)
+
+	lock_kernel();
+	if (in_use) {
+		unlock_kernel();
 		return -EBUSY;
+	}
 
 	in_use = 1;
 
 	dac_audio_start();
-
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/sound/oss/soundcard.c b/sound/oss/soundcard.c
index 2d9c513..92aa762 100644
--- a/sound/oss/soundcard.c
+++ b/sound/oss/soundcard.c
@@ -210,42 +210,44 @@ static int sound_open(struct inode *inode, struct file *file)
 		printk(KERN_ERR "Invalid minor device %d\n", dev);
 		return -ENXIO;
 	}
+	lock_kernel();
 	switch (dev & 0x0f) {
 	case SND_DEV_CTL:
 		dev >>= 4;
 		if (dev >= 0 && dev < MAX_MIXER_DEV && mixer_devs[dev] == NULL) {
 			request_module("mixer%d", dev);
 		}
+		retval = -ENXIO;
 		if (dev && (dev >= num_mixers || mixer_devs[dev] == NULL))
-			return -ENXIO;
+			break;
 	
 		if (!try_module_get(mixer_devs[dev]->owner))
-			return -ENXIO;
+			break;
+
+		retval = 0;
 		break;
 
 	case SND_DEV_SEQ:
 	case SND_DEV_SEQ2:
-		if ((retval = sequencer_open(dev, file)) < 0)
-			return retval;
+		retval = sequencer_open(dev, file);
 		break;
 
 	case SND_DEV_MIDIN:
-		if ((retval = MIDIbuf_open(dev, file)) < 0)
-			return retval;
+		retval = MIDIbuf_open(dev, file);
 		break;
 
 	case SND_DEV_DSP:
 	case SND_DEV_DSP16:
 	case SND_DEV_AUDIO:
-		if ((retval = audio_open(dev, file)) < 0)
-			return retval;
+		retval = audio_open(dev, file);
 		break;
 
 	default:
 		printk(KERN_ERR "Invalid minor device %d\n", dev);
-		return -ENXIO;
+		retval = -ENXIO;
 	}
 
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/sound/oss/swarm_cs4297a.c b/sound/oss/swarm_cs4297a.c
index 3136c88..34b0838 100644
--- a/sound/oss/swarm_cs4297a.c
+++ b/sound/oss/swarm_cs4297a.c
@@ -68,6 +68,7 @@
 #include <linux/delay.h>
 #include <linux/sound.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <linux/soundcard.h>
 #include <linux/ac97_codec.h>
 #include <linux/pci.h>
@@ -1534,6 +1535,7 @@ static int cs4297a_open_mixdev(struct inode *inode, struct file *file)
 	CS_DBGOUT(CS_FUNCTION | CS_OPEN, 4,
 		  printk(KERN_INFO "cs4297a: cs4297a_open_mixdev()+\n"));
 
+	lock_kernel();
 	list_for_each(entry, &cs4297a_devs)
 	{
 		s = list_entry(entry, struct cs4297a_state, list);
@@ -1544,6 +1546,8 @@ static int cs4297a_open_mixdev(struct inode *inode, struct file *file)
 	{
 		CS_DBGOUT(CS_FUNCTION | CS_OPEN | CS_ERROR, 2,
 			printk(KERN_INFO "cs4297a: cs4297a_open_mixdev()- -ENODEV\n"));
+
+		unlock_kernel();
 		return -ENODEV;
 	}
 	VALIDATE_STATE(s);
@@ -1551,6 +1555,7 @@ static int cs4297a_open_mixdev(struct inode *inode, struct file *file)
 
 	CS_DBGOUT(CS_FUNCTION | CS_OPEN, 4,
 		  printk(KERN_INFO "cs4297a: cs4297a_open_mixdev()- 0\n"));
+	unlock_kernel();
 
 	return nonseekable_open(inode, file);
 }
@@ -2369,7 +2374,7 @@ static int cs4297a_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static int cs4297a_open(struct inode *inode, struct file *file)
+static int cs4297a_locked_open(struct inode *inode, struct file *file)
 {
 	int minor = iminor(inode);
 	struct cs4297a_state *s=NULL;
@@ -2486,6 +2491,16 @@ static int cs4297a_open(struct inode *inode, struct file *file)
 	return nonseekable_open(inode, file);
 }
 
+static int cs4297a_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	lock_kernel();
+	ret = cs4297a_open(inode, file);
+	unlock_kernel();
+
+	return ret;
+}
 
 // ******************************************************************************************
 //   Wave (audio) file operations struct.
diff --git a/sound/oss/vwsnd.c b/sound/oss/vwsnd.c
index 20b3b32..99c94c4 100644
--- a/sound/oss/vwsnd.c
+++ b/sound/oss/vwsnd.c
@@ -2921,6 +2921,7 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
 
 	DBGE("(inode=0x%p, file=0x%p)\n", inode, file);
 
+	lock_kernel();
 	INC_USE_COUNT;
 	for (devc = vwsnd_dev_list; devc; devc = devc->next_dev)
 		if ((devc->audio_minor & ~0x0F) == (minor & ~0x0F))
@@ -2928,6 +2929,7 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
 
 	if (devc == NULL) {
 		DEC_USE_COUNT;
+		unlock_kernel();
 		return -ENODEV;
 	}
 
@@ -2936,11 +2938,13 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
 		mutex_unlock(&devc->open_mutex);
 		if (file->f_flags & O_NONBLOCK) {
 			DEC_USE_COUNT;
+			unlock_kernel();
 			return -EBUSY;
 		}
 		interruptible_sleep_on(&devc->open_wait);
 		if (signal_pending(current)) {
 			DEC_USE_COUNT;
+			unlock_kernel();
 			return -ERESTARTSYS;
 		}
 		mutex_lock(&devc->open_mutex);
@@ -2993,6 +2997,7 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
 
 	file->private_data = devc;
 	DBGRV();
+	unlock_kernel();
 	return 0;
 }
 
@@ -3062,15 +3067,18 @@ static int vwsnd_mixer_open(struct inode *inode, struct file *file)
 	DBGEV("(inode=0x%p, file=0x%p)\n", inode, file);
 
 	INC_USE_COUNT;
+	lock_kernel();
 	for (devc = vwsnd_dev_list; devc; devc = devc->next_dev)
 		if (devc->mixer_minor == iminor(inode))
 			break;
 
 	if (devc == NULL) {
 		DEC_USE_COUNT;
+		unlock_kernel();
 		return -ENODEV;
 	}
 	file->private_data = devc;
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/sound/sound_core.c b/sound/sound_core.c
index c8627fc..cb61317 100644
--- a/sound/sound_core.c
+++ b/sound/sound_core.c
@@ -629,12 +629,8 @@ static int soundcore_open(struct inode *inode, struct file *file)
 		file->f_op = new_fops;
 		spin_unlock(&sound_loader_lock);
 
-		if (file->f_op->open) {
-			/* TODO: push down BKL into indivial open functions */
-			lock_kernel();
+		if (file->f_op->open)
 			err = file->f_op->open(inode,file);
-			unlock_kernel();
-		}
 
 		if (err) {
 			fops_put(file->f_op);

Re: [PATCH 2/3] Remove BKL from fs/locks.c

[Arnd Bergmann]

On Sunday 11 July 2010 00:01:10 Christoph Hellwig wrote:
> On Sat, Jul 10, 2010 at 11:51:40PM +0200, Arnd Bergmann wrote:
> > From: Matthew Wilcox <willy@linux.intel.com>
> > 
> > I've taken a patch originally written by Matthew Wilcox and
> > ported it to the current version. Unfortunately, the change
> > conflicts with the use of lockd, which still heavily uses
> > the big kernel lock.
> > 
> > As a workaround, I've made the behaviour configurable,
> > it either uses the BKL when it's enabled or a spinlock
> > when the BKL (and consequently nfs and lockd) are
> > disabled.
> 
> Defintively not something we want in mainline.  But keep poking
> the nfs guys to sort the lockd mess out for real.

Yes, that was the idea. This is the last patch I need to run
all of my machines without the BKL, so I spent a few hours
looking at how to fix lockd. When I couldn't figure it out,
I decided to do an evil hack that happens to work, in order
to build pressure.

	Arnd

Re: [PATCH 3/3] sound: push BKL into open functions

[Takashi Iwai]

At Sun, 11 Jul 2010 12:16:36 +0200,
Arnd Bergmann wrote:
> 
> This moves the lock_kernel() call from soundcore_open
> to the individual OSS device drivers, where we can deal
> with it one driver at a time if needed, or just kill
> off the drivers.
> 
> All core components in ALSA already provide
> adequate locking in their open()-functions
> and do not require the big kernel lock, so
> there is no need to add the BKL there.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> On Sunday 11 July 2010 09:15:22 Jaroslav Kysela wrote:
> > I don't see any reason (benefit) to add gotos to these two functions.
> > 
> Sorry, I had removed them and then forgot the git-add before
> creating the emails. Originally, I had two patches, one for
> pushing down the BKL into every sound driver (hence the goto)
> and a second patch to remove the BKL again from all the native
> alsa drivers. If you prefer, I can also give you the separate
> patches, but I figured that since none of the ALSA drivers needs
> the BKL, the combined patch would be better.
> 
> This is the corrected combined version.

Thanks.  I applied now to sound git tree (with a minor fix of
coding-style in sound/oss/au1550_ac97.c).

BTW, do you have an updated patch for native_ioctl conversion wrt
sound/*?


Takashi

Re: [PATCH 3/3] sound: push BKL into open functions

[Takashi Iwai]

At Sun, 11 Jul 2010 12:16:36 +0200,
Arnd Bergmann wrote:
> 
> This moves the lock_kernel() call from soundcore_open
> to the individual OSS device drivers, where we can deal
> with it one driver at a time if needed, or just kill
> off the drivers.
> 
> All core components in ALSA already provide
> adequate locking in their open()-functions
> and do not require the big kernel lock, so
> there is no need to add the BKL there.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> On Sunday 11 July 2010 09:15:22 Jaroslav Kysela wrote:
> > I don't see any reason (benefit) to add gotos to these two functions.
> > 
> Sorry, I had removed them and then forgot the git-add before
> creating the emails. Originally, I had two patches, one for
> pushing down the BKL into every sound driver (hence the goto)
> and a second patch to remove the BKL again from all the native
> alsa drivers. If you prefer, I can also give you the separate
> patches, but I figured that since none of the ALSA drivers needs
> the BKL, the combined patch would be better.
> 
> This is the corrected combined version.

Thanks.  I applied now to sound git tree (with a minor fix of
coding-style in sound/oss/au1550_ac97.c).

BTW, do you have an updated patch for native_ioctl conversion wrt
sound/*?


Takashi

[PATCH] sound/oss: convert to unlocked_ioctl

[Arnd Bergmann]

These are the final conversions for the ioctl file operation so we can remove
it in the next merge window.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: alsa-devel@alsa-project.org
---
On Monday 12 July 2010 17:53:32 Takashi Iwai wrote:
> 
> BTW, do you have an updated patch for native_ioctl conversion wrt
> sound/*?

Almost forgot that, thanks for reminding me!

	Arnd
---

 sound/oss/au1550_ac97.c            |   54 ++++++++++++++++++++++-------------
 sound/oss/dmasound/dmasound_core.c |   35 ++++++++++++++++++----
 sound/oss/msnd_pinnacle.c          |   15 ++++++---
 sound/oss/sh_dac_audio.c           |   18 ++++++++++--
 sound/oss/swarm_cs4297a.c          |   24 ++++++++++++---
 sound/oss/vwsnd.c                  |   24 ++++++++-------
 6 files changed, 119 insertions(+), 51 deletions(-)

diff --git a/sound/oss/au1550_ac97.c b/sound/oss/au1550_ac97.c
index fb913e5..0fd256c 100644
--- a/sound/oss/au1550_ac97.c
+++ b/sound/oss/au1550_ac97.c
@@ -827,22 +827,26 @@ mixdev_ioctl(struct ac97_codec *codec, unsigned int cmd,
 	return codec->mixer_ioctl(codec, cmd, arg);
 }
 
-static int
-au1550_ioctl_mixdev(struct inode *inode, struct file *file,
-			       unsigned int cmd, unsigned long arg)
+static long
+au1550_ioctl_mixdev(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct au1550_state *s = (struct au1550_state *)file->private_data;
 	struct ac97_codec *codec = s->codec;
+	int ret;
+
+	lock_kernel();
+	ret = mixdev_ioctl(codec, cmd, arg);
+	unlock_kernel();
 
-	return mixdev_ioctl(codec, cmd, arg);
+	return ret;
 }
 
 static /*const */ struct file_operations au1550_mixer_fops = {
-	owner:THIS_MODULE,
-	llseek:au1550_llseek,
-	ioctl:au1550_ioctl_mixdev,
-	open:au1550_open_mixdev,
-	release:au1550_release_mixdev,
+	.owner		= THIS_MODULE,
+	.llseek		= au1550_llseek,
+	.unlocked_ioctl	= au1550_ioctl_mixdev,
+	.open		= au1550_open_mixdev,
+	.release	= au1550_release_mixdev,
 };
 
 static int
@@ -1346,8 +1350,7 @@ dma_count_done(struct dmabuf *db)
 
 
 static int
-au1550_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
-							unsigned long arg)
+au1550_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct au1550_state *s = (struct au1550_state *)file->private_data;
 	unsigned long   flags;
@@ -1783,6 +1786,17 @@ au1550_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 	return mixdev_ioctl(s->codec, cmd, arg);
 }
 
+static long
+au1550_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int ret;
+
+	lock_kernel();
+	ret = au1550_ioctl(file, cmd, arg);
+	unlock_kernel();
+
+	return ret;
+}
 
 static int
 au1550_open(struct inode *inode, struct file *file)
@@ -1893,15 +1907,15 @@ au1550_release(struct inode *inode, struct file *file)
 }
 
 static /*const */ struct file_operations au1550_audio_fops = {
-	owner:		THIS_MODULE,
-	llseek:		au1550_llseek,
-	read:		au1550_read,
-	write:		au1550_write,
-	poll:		au1550_poll,
-	ioctl:		au1550_ioctl,
-	mmap:		au1550_mmap,
-	open:		au1550_open,
-	release:	au1550_release,
+	.owner		= THIS_MODULE,
+	.llseek		= au1550_llseek,
+	.read		= au1550_read,
+	.write		= au1550_write,
+	.poll		= au1550_poll,
+	.unlocked_ioctl	= au1550_unlocked_ioctl,
+	.mmap		= au1550_mmap,
+	.open		= au1550_open,
+	.release	= au1550_release,
 };
 
 MODULE_AUTHOR("Advanced Micro Devices (AMD), dan@embeddededge.com");
diff --git a/sound/oss/dmasound/dmasound_core.c b/sound/oss/dmasound/dmasound_core.c
index 5a4f38c..6ecd41a 100644
--- a/sound/oss/dmasound/dmasound_core.c
+++ b/sound/oss/dmasound/dmasound_core.c
@@ -341,8 +341,8 @@ static int mixer_release(struct inode *inode, struct file *file)
 	unlock_kernel();
 	return 0;
 }
-static int mixer_ioctl(struct inode *inode, struct file *file, u_int cmd,
-		       u_long arg)
+
+static int mixer_ioctl(struct file *file, u_int cmd, u_long arg)
 {
 	if (_SIOC_DIR(cmd) & _SIOC_WRITE)
 	    mixer.modify_counter++;
@@ -366,11 +366,22 @@ static int mixer_ioctl(struct inode *inode, struct file *file, u_int cmd,
 	return -EINVAL;
 }
 
+static long mixer_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
+{
+	int ret;
+
+	lock_kernel();
+	ret = mixer_ioctl(file, cmd, arg);
+	unlock_kernel();
+
+	return ret;
+}
+
 static const struct file_operations mixer_fops =
 {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
-	.ioctl		= mixer_ioctl,
+	.unlocked_ioctl	= mixer_unlocked_ioctl,
 	.open		= mixer_open,
 	.release	= mixer_release,
 };
@@ -963,8 +974,7 @@ printk("dmasound_core: tried to set_queue_frags on a locked queue\n") ;
 	return 0 ;
 }
 
-static int sq_ioctl(struct inode *inode, struct file *file, u_int cmd,
-		    u_long arg)
+static int sq_ioctl(struct file *file, u_int cmd, u_long arg)
 {
 	int val, result;
 	u_long fmt;
@@ -1122,18 +1132,29 @@ static int sq_ioctl(struct inode *inode, struct file *file, u_int cmd,
 		return IOCTL_OUT(arg,val);
 
 	default:
-		return mixer_ioctl(inode, file, cmd, arg);
+		return mixer_ioctl(file, cmd, arg);
 	}
 	return -EINVAL;
 }
 
+static long sq_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
+{
+	int ret;
+
+	lock_kernel();
+	ret = sq_ioctl(file, cmd, arg);
+	unlock_kernel();
+
+	return ret;
+}
+
 static const struct file_operations sq_fops =
 {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.write		= sq_write,
 	.poll		= sq_poll,
-	.ioctl		= sq_ioctl,
+	.unlocked_ioctl	= sq_unlocked_ioctl,
 	.open		= sq_open,
 	.release	= sq_release,
 };
diff --git a/sound/oss/msnd_pinnacle.c b/sound/oss/msnd_pinnacle.c
index 153d822..9ffd29f 100644
--- a/sound/oss/msnd_pinnacle.c
+++ b/sound/oss/msnd_pinnacle.c
@@ -639,21 +639,26 @@ static int mixer_ioctl(unsigned int cmd, unsigned long arg)
 	return -EINVAL;
 }
 
-static int dev_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
+static long dev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	int minor = iminor(inode);
+	int ret;
 
 	if (cmd == OSS_GETVERSION) {
 		int sound_version = SOUND_VERSION;
 		return put_user(sound_version, (int __user *)arg);
 	}
 
+	ret = -EINVAL;
+
+	lock_kernel();
 	if (minor == dev.dsp_minor)
-		return dsp_ioctl(file, cmd, arg);
+		ret = dsp_ioctl(file, cmd, arg);
 	else if (minor == dev.mixer_minor)
-		return mixer_ioctl(cmd, arg);
+		ret = mixer_ioctl(cmd, arg);
+	unlock_kernel();
 
-	return -EINVAL;
+	return ret;
 }
 
 static void dsp_write_flush(void)
@@ -1109,7 +1114,7 @@ static const struct file_operations dev_fileops = {
 	.owner		= THIS_MODULE,
 	.read		= dev_read,
 	.write		= dev_write,
-	.ioctl		= dev_ioctl,
+	.unlocked_ioctl	= dev_ioctl,
 	.open		= dev_open,
 	.release	= dev_release,
 };
diff --git a/sound/oss/sh_dac_audio.c b/sound/oss/sh_dac_audio.c
index 8f0be40..fdb58eb 100644
--- a/sound/oss/sh_dac_audio.c
+++ b/sound/oss/sh_dac_audio.c
@@ -15,6 +15,7 @@
 #include <linux/linkage.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
+#include <linux/smp_lock.h>
 #include <linux/sound.h>
 #include <linux/smp_lock.h>
 #include <linux/soundcard.h>
@@ -93,7 +94,7 @@ static void dac_audio_set_rate(void)
 	wakeups_per_second = ktime_set(0, 1000000000 / rate);
 }
 
-static int dac_audio_ioctl(struct inode *inode, struct file *file,
+static int dac_audio_ioctl(struct file *file,
 			   unsigned int cmd, unsigned long arg)
 {
 	int val;
@@ -159,6 +160,17 @@ static int dac_audio_ioctl(struct inode *inode, struct file *file,
 	return -EINVAL;
 }
 
+static long dac_audio_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
+{
+	int ret;
+
+	lock_kernel();
+	ret = dac_audio_ioctl(file, cmd, arg);
+	unlock_kernel();
+
+	return ret;
+}
+
 static ssize_t dac_audio_write(struct file *file, const char *buf, size_t count,
 			       loff_t * ppos)
 {
@@ -242,8 +254,8 @@ static int dac_audio_release(struct inode *inode, struct file *file)
 
 const struct file_operations dac_audio_fops = {
       .read =		dac_audio_read,
-      .write =	dac_audio_write,
-      .ioctl =	dac_audio_ioctl,
+      .write =		dac_audio_write,
+      .unlocked_ioctl =	dac_audio_unlocked_ioctl,
       .open =		dac_audio_open,
       .release =	dac_audio_release,
 };
diff --git a/sound/oss/swarm_cs4297a.c b/sound/oss/swarm_cs4297a.c
index 34b0838..b15840a 100644
--- a/sound/oss/swarm_cs4297a.c
+++ b/sound/oss/swarm_cs4297a.c
@@ -1571,11 +1571,15 @@ static int cs4297a_release_mixdev(struct inode *inode, struct file *file)
 }
 
 
-static int cs4297a_ioctl_mixdev(struct inode *inode, struct file *file,
+static int cs4297a_ioctl_mixdev(struct file *file,
 			       unsigned int cmd, unsigned long arg)
 {
-	return mixer_ioctl((struct cs4297a_state *) file->private_data, cmd,
+	int ret;
+	lock_kernel();
+	ret = mixer_ioctl((struct cs4297a_state *) file->private_data, cmd,
 			   arg);
+	unlock_kernel();
+	return ret;
 }
 
 
@@ -1585,7 +1589,7 @@ static int cs4297a_ioctl_mixdev(struct inode *inode, struct file *file,
 static const struct file_operations cs4297a_mixer_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
-	.ioctl		= cs4297a_ioctl_mixdev,
+	.unlocked_ioctl	= cs4297a_ioctl_mixdev,
 	.open		= cs4297a_open_mixdev,
 	.release	= cs4297a_release_mixdev,
 };
@@ -1949,7 +1953,7 @@ static int cs4297a_mmap(struct file *file, struct vm_area_struct *vma)
 }
 
 
-static int cs4297a_ioctl(struct inode *inode, struct file *file,
+static int cs4297a_ioctl(struct file *file,
 			unsigned int cmd, unsigned long arg)
 {
 	struct cs4297a_state *s =
@@ -2342,6 +2346,16 @@ static int cs4297a_ioctl(struct inode *inode, struct file *file,
 	return mixer_ioctl(s, cmd, arg);
 }
 
+static long cs4297a_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
+{
+	int ret;
+
+	lock_kernel();
+	ret = cs4297a_ioctl(file, cmd, arg);
+	unlock_kernel();
+
+	return ret;
+}
 
 static int cs4297a_release(struct inode *inode, struct file *file)
 {
@@ -2511,7 +2525,7 @@ static const struct file_operations cs4297a_audio_fops = {
 	.read		= cs4297a_read,
 	.write		= cs4297a_write,
 	.poll		= cs4297a_poll,
-	.ioctl		= cs4297a_ioctl,
+	.unlocked_ioctl	= cs4297a_unlocked_ioctl,
 	.mmap		= cs4297a_mmap,
 	.open		= cs4297a_open,
 	.release	= cs4297a_release,
diff --git a/sound/oss/vwsnd.c b/sound/oss/vwsnd.c
index 99c94c4..8cd73cd 100644
--- a/sound/oss/vwsnd.c
+++ b/sound/oss/vwsnd.c
@@ -2429,8 +2429,7 @@ static unsigned int vwsnd_audio_poll(struct file *file,
 	return mask;
 }
 
-static int vwsnd_audio_do_ioctl(struct inode *inode,
-				struct file *file,
+static int vwsnd_audio_do_ioctl(struct file *file,
 				unsigned int cmd,
 				unsigned long arg)
 {
@@ -2446,8 +2445,8 @@ static int vwsnd_audio_do_ioctl(struct inode *inode,
 	int ival;
 
 	
-	DBGEV("(inode=0x%p, file=0x%p, cmd=0x%x, arg=0x%lx)\n",
-	      inode, file, cmd, arg);
+	DBGEV("(file=0x%p, cmd=0x%x, arg=0x%lx)\n",
+	      file, cmd, arg);
 	switch (cmd) {
 	case OSS_GETVERSION:		/* _SIOR ('M', 118, int) */
 		DBGX("OSS_GETVERSION\n");
@@ -2885,17 +2884,19 @@ static int vwsnd_audio_do_ioctl(struct inode *inode,
 	return -EINVAL;
 }
 
-static int vwsnd_audio_ioctl(struct inode *inode,
-				struct file *file,
+static long vwsnd_audio_ioctl(struct file *file,
 				unsigned int cmd,
 				unsigned long arg)
 {
 	vwsnd_dev_t *devc = (vwsnd_dev_t *) file->private_data;
 	int ret;
 
+	lock_kernel();
 	mutex_lock(&devc->io_mutex);
-	ret = vwsnd_audio_do_ioctl(inode, file, cmd, arg);
+	ret = vwsnd_audio_do_ioctl(file, cmd, arg);
 	mutex_unlock(&devc->io_mutex);
+	unlock_kernel();
+
 	return ret;
 }
 
@@ -3049,7 +3050,7 @@ static const struct file_operations vwsnd_audio_fops = {
 	.read =		vwsnd_audio_read,
 	.write =	vwsnd_audio_write,
 	.poll =		vwsnd_audio_poll,
-	.ioctl =	vwsnd_audio_ioctl,
+	.unlocked_ioctl = vwsnd_audio_ioctl,
 	.mmap =		vwsnd_audio_mmap,
 	.open =		vwsnd_audio_open,
 	.release =	vwsnd_audio_release,
@@ -3211,8 +3212,7 @@ static int mixer_write_ioctl(vwsnd_dev_t *devc, unsigned int nr, void __user *ar
 
 /* This is the ioctl entry to the mixer driver. */
 
-static int vwsnd_mixer_ioctl(struct inode *ioctl,
-			      struct file *file,
+static long vwsnd_mixer_ioctl(struct file *file,
 			      unsigned int cmd,
 			      unsigned long arg)
 {
@@ -3223,6 +3223,7 @@ static int vwsnd_mixer_ioctl(struct inode *ioctl,
 
 	DBGEV("(devc=0x%p, cmd=0x%x, arg=0x%lx)\n", devc, cmd, arg);
 
+	lock_kernel();
 	mutex_lock(&devc->mix_mutex);
 	{
 		if ((cmd & ~nrmask) == MIXER_READ(0))
@@ -3233,13 +3234,14 @@ static int vwsnd_mixer_ioctl(struct inode *ioctl,
 			retval = -EINVAL;
 	}
 	mutex_unlock(&devc->mix_mutex);
+	unlock_kernel();
 	return retval;
 }
 
 static const struct file_operations vwsnd_mixer_fops = {
 	.owner =	THIS_MODULE,
 	.llseek =	no_llseek,
-	.ioctl =	vwsnd_mixer_ioctl,
+	.unlocked_ioctl = vwsnd_mixer_ioctl,
 	.open =		vwsnd_mixer_open,
 	.release =	vwsnd_mixer_release,
 };
-- 
1.7.1

Re: [PATCH] sound/oss: convert to unlocked_ioctl

[Takashi Iwai]

At Mon, 12 Jul 2010 19:53:18 +0200,
Arnd Bergmann wrote:
> 
> These are the final conversions for the ioctl file operation so we can remove
> it in the next merge window.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Cc: Jaroslav Kysela <perex@perex.cz>
> Cc: Takashi Iwai <tiwai@suse.de>
> Cc: alsa-devel@alsa-project.org
> ---
> On Monday 12 July 2010 17:53:32 Takashi Iwai wrote:
> > 
> > BTW, do you have an updated patch for native_ioctl conversion wrt
> > sound/*?
> 
> Almost forgot that, thanks for reminding me!

Thanks, applied now.

Now the rest is eliminating each lock_kernel() in sound/oss/*.c :)


Takashi

Re: [PATCH] sound/oss: convert to unlocked_ioctl

[Takashi Iwai]

At Mon, 12 Jul 2010 19:53:18 +0200,
Arnd Bergmann wrote:
> 
> These are the final conversions for the ioctl file operation so we can remove
> it in the next merge window.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Cc: Jaroslav Kysela <perex@perex.cz>
> Cc: Takashi Iwai <tiwai@suse.de>
> Cc: alsa-devel@alsa-project.org
> ---
> On Monday 12 July 2010 17:53:32 Takashi Iwai wrote:
> > 
> > BTW, do you have an updated patch for native_ioctl conversion wrt
> > sound/*?
> 
> Almost forgot that, thanks for reminding me!

Thanks, applied now.

Now the rest is eliminating each lock_kernel() in sound/oss/*.c :)


Takashi

Re: [PATCH] sound/oss: convert to unlocked_ioctl

[Arnd Bergmann]

On Monday 12 July 2010 22:38:25 Takashi Iwai wrote:
> Now the rest is eliminating each lock_kernel() in sound/oss/*.c :)

For other files, I've used a script (see below) to do this, it probably
works with the OSS files as well, although I have not tried yet.

Of course, another option for OSS device drivers would be to
remove the entire driver ;). Either way, my feeling is that the
OSS drivers are not stopping anyone from building a kernel without
CONFIG_BKL once we have introduced that symbol and made the drivers
depend on it.

	Arnd

---
#!/bin/bash
file=$1
name=$2
if grep -q lock_kernel ${file} ; then
    if grep -q 'include.*linux.mutex.h' ${file} ; then
            sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
    else
            sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
    fi
    sed -i ${file} \
        -e "/^#include.*linux.mutex.h/,$ {
                1,/^\(static\|int\|long\)/ {
                     /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }"  \
    -e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
    -e '/[      ]*cycle_kernel_lock();/d'
else
    sed -i -e '/include.*\<smp_lock.h\>/d' ${file}  \
                -e '/cycle_kernel_lock()/d'
fi

Re: [PATCH 1/3] drm: kill BKL from common code

[Andreas Schwab]

Arnd Bergmann <arnd@arndb.de> writes:

> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 4a66201..76d98f4 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -506,9 +506,9 @@ long drm_ioctl(struct file *filp,
>  		if (ioctl->flags & DRM_UNLOCKED)
>  			retcode = func(dev, kdata, file_priv);
>  		else {
> -			lock_kernel();
> +			mutex_lock(&drm_global_mutex);
>  			retcode = func(dev, kdata, file_priv);
> -			unlock_kernel();
> +			mutex_unlock(&drm_global_mutex);

How is this supposed to work in the context of sleeping ioctls, like
drm_lock?

[drm:drm_ioctl], pid=2461, cmd=0x8008642a, nr=0x2a, dev 0xe200, auth=1
[drm:drm_lock], 1 (pid 2461) requests lock (0x80000003), flags = 0x00000000
[drm:drm_ioctl], pid=2520, cmd=0x8008642b, nr=0x2b, dev 0xe200, auth=1

# ps 2461 2520
  PID TTY      STAT   TIME COMMAND
 2461 tty7     Ss+    0:01 /usr/bin/Xorg -br :0 vt7 -nolisten tcp -auth /var/lib
 2520 pts/2    D+     0:00 glxgears

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: [PATCH 1/3] drm: kill BKL from common code

[Arnd Bergmann]

On Tuesday 24 August 2010 20:46:40 Andreas Schwab wrote:
> Arnd Bergmann <arnd@arndb.de> writes:
> 
> > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > index 4a66201..76d98f4 100644
> > --- a/drivers/gpu/drm/drm_drv.c
> > +++ b/drivers/gpu/drm/drm_drv.c
> > @@ -506,9 +506,9 @@ long drm_ioctl(struct file *filp,
> >               if (ioctl->flags & DRM_UNLOCKED)
> >                       retcode = func(dev, kdata, file_priv);
> >               else {
> > -                     lock_kernel();
> > +                     mutex_lock(&drm_global_mutex);
> >                       retcode = func(dev, kdata, file_priv);
> > -                     unlock_kernel();
> > +                     mutex_unlock(&drm_global_mutex);
> 
> How is this supposed to work in the context of sleeping ioctls, like
> drm_lock?
> 
> [drm:drm_ioctl], pid=2461, cmd=0x8008642a, nr=0x2a, dev 0xe200, auth=1
> [drm:drm_lock], 1 (pid 2461) requests lock (0x80000003), flags = 0x00000000
> [drm:drm_ioctl], pid=2520, cmd=0x8008642b, nr=0x2b, dev 0xe200, auth=1
> 
> # ps 2461 2520
>   PID TTY      STAT   TIME COMMAND
>  2461 tty7     Ss+    0:01 /usr/bin/Xorg -br :0 vt7 -nolisten tcp -auth /var/lib
>  2520 pts/2    D+     0:00 glxgears

I was assuming that no ioctl sleeps indefinitely, which is normally the
case. As I described in the changelog, all locked ioctls are serialized
with the drm_global_mutex, while they used to be only serialized when
not sleeping before.

I did not realize that DRM has mutexes that are held across ioctls.
To restore the old behavior, apply this patch:

diff --git a/drivers/gpu/drm/drm_lock.c b/drivers/gpu/drm/drm_lock.c
index e2f70a5..9bf93bc 100644
--- a/drivers/gpu/drm/drm_lock.c
+++ b/drivers/gpu/drm/drm_lock.c
@@ -92,7 +92,9 @@ int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv)
 		}
 
 		/* Contention */
+		mutex_unlock(&drm_global_mutex);
 		schedule();
+		mutex_lock(&drm_global_mutex);
 		if (signal_pending(current)) {
 			ret = -EINTR;
 			break;

However, it would be better instead to mark the drm_lock and drm_unlock
ioctls as DRM_UNLOCKED so they are not called under drm_global_mutex to
start with, like this:

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 90288ec..469bc18 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -91,8 +91,8 @@ static struct drm_ioctl_desc drm_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_IOCTL_ADD_DRAW, drm_adddraw, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 	DRM_IOCTL_DEF(DRM_IOCTL_RM_DRAW, drm_rmdraw, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 
-	DRM_IOCTL_DEF(DRM_IOCTL_LOCK, drm_lock, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_IOCTL_UNLOCK, drm_unlock, DRM_AUTH),
+	DRM_IOCTL_DEF(DRM_IOCTL_LOCK, drm_lock, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_IOCTL_UNLOCK, drm_unlock, DRM_AUTH|DRM_UNLOCKED),
 
 	DRM_IOCTL_DEF(DRM_IOCTL_FINISH, drm_noop, DRM_AUTH),

Ideally, all the ioctls should be marked as DRM_UNLOCKED and the path calling
ioctl under drm_global_mutex be removed, but that requires auditing of each
call by someone who understands the drm locking better than I do.

Apply only one of the two patches at a time, they are mutually exclusive.

	Arnd