From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>
Cc: Zhen Lei <thunder.leizhen@huawei.com>,
Thomas Zimmermann <tzimmermann@suse.de>,
Xiyu Yang <xiyuyang19@fudan.edu.cn>,
Du Cheng <ducheng2@gmail.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
Zheyu Ma <zheyuma97@gmail.com>,
Matthew Wilcox <willy@infradead.org>,
William Kucharski <william.kucharski@oracle.com>,
Claudio Suarez <cssk@net-c.es>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alex Deucher <alexander.deucher@amd.com>,
Daniel Vetter <daniel.vetter@intel.com>,
Sam Ravnborg <sam@ravnborg.org>
Subject: [PATCH v3 12/17] fbcon: use lock_fb_info in fbcon_open/release
Date: Tue, 5 Apr 2022 23:03:30 +0200 [thread overview]
Message-ID: <20220405210335.3434130-13-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <20220405210335.3434130-1-daniel.vetter@ffwll.ch>
Now we get to the real motiviation, because fbmem.c insists that
that's the right lock for these.
Ofc fbcon.c has a lot more places where it probably should call
lock_fb_info(). But looking at fbmem.c at least most of these seem to
be protected by console_lock() too, which is probably what papers over
any issues.
Note that this means we're shuffling around a bit the locking sections
for some of the console takeover and unbind paths, but not all:
- console binding/unbinding from the console layer never with
lock_fb_info
- unbind (as opposed to unlink) never bother with lock_fb_info
Also the real serialization against set_par and set_pan are still
doing by wrapping the entire ioctl code in console_lock(). So this
shuffling shouldn't be worse than what we had from a "can you trigger
races?" pov, but it's at least clearer.
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Claudio Suarez <cssk@net-c.es>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Du Cheng <ducheng2@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Zheyu Ma <zheyuma97@gmail.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn>
---
drivers/video/fbdev/core/fbcon.c | 5 +++++
drivers/video/fbdev/core/fbmem.c | 4 ----
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index f0213a0e3870..cc960bf49991 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -684,8 +684,10 @@ static int fbcon_invalid_charcount(struct fb_info *info, unsigned charcount)
static void fbcon_release(struct fb_info *info)
{
+ lock_fb_info(info);
if (info->fbops->fb_release)
info->fbops->fb_release(info, 0);
+ unlock_fb_info(info);
module_put(info->fbops->owner);
}
@@ -697,11 +699,14 @@ static int fbcon_open(struct fb_info *info)
if (!try_module_get(info->fbops->owner))
return -ENODEV;
+ lock_fb_info(info);
if (info->fbops->fb_open &&
info->fbops->fb_open(info, 0)) {
+ unlock_fb_info(info);
module_put(info->fbops->owner);
return -ENODEV;
}
+ unlock_fb_info(info);
ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
if (!ops) {
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 34d6bb1bf82e..0e68d9456bc2 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1670,9 +1670,7 @@ static int do_register_framebuffer(struct fb_info *fb_info)
console_lock();
else
atomic_inc(&ignore_console_lock_warning);
- lock_fb_info(fb_info);
ret = fbcon_fb_registered(fb_info);
- unlock_fb_info(fb_info);
if (!lockless_register_fb)
console_unlock();
@@ -1689,9 +1687,7 @@ static void unbind_console(struct fb_info *fb_info)
return;
console_lock();
- lock_fb_info(fb_info);
fbcon_fb_unbind(fb_info);
- unlock_fb_info(fb_info);
console_unlock();
}
--
2.34.1
next prev parent reply other threads:[~2022-04-05 21:04 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-05 21:03 [PATCH v3 00/17] fbcon cleanups Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 01/17] fbcon: delete a few unneeded forward decl Daniel Vetter
2022-04-05 23:36 ` Fabio Estevam
2022-04-05 21:03 ` [PATCH v3 02/17] fbcon: Move fbcon_bmove(_rec) functions Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 03/17] fbcon: Introduce wrapper for console->fb_info lookup Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 04/17] fbcon: delete delayed loading code Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 05/17] fbdev/sysfs: Fix locking Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 06/17] fbcon: Use delayed work for cursor Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 07/17] fbcon: Replace FBCON_FLAGS_INIT with a boolean Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 08/17] fb: Delete fb_info->queue Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 09/17] fbcon: Extract fbcon_open/release helpers Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 10/17] fbcon: Ditch error handling for con2fb_release_oldinfo Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 11/17] fbcon: move more common code into fb_open() Daniel Vetter
2022-04-05 21:03 ` Daniel Vetter [this message]
2022-04-05 21:03 ` [PATCH v3 13/17] fbcon: Consistently protect deferred_takeover with console_lock() Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 14/17] fbcon: Move console_lock for register/unlink/unregister Daniel Vetter
2022-04-11 22:27 ` Nathan Chancellor
2022-04-13 8:13 ` Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 15/17] fbcon: Move more code into fbcon_release Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 16/17] fbcon: untangle fbcon_exit Daniel Vetter
2022-04-05 21:03 ` [PATCH v3 17/17] fbcon: Maintain a private array of fb_info Daniel Vetter
2022-04-08 7:51 ` [PATCH v3 00/17] fbcon cleanups Daniel Vetter
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