diff options
| author | Krzysztof Helt <krzysztof.h1@wp.pl> | 2009-06-30 11:41:29 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-30 18:56:00 -0700 |
| commit | 537a1bf059fa312355696fa6db80726e655e7f17 (patch) | |
| tree | 4f5b3c6917311cfefad21eaf3dd92978334282de /drivers/video/matrox/matroxfb_base.c | |
| parent | 70d6027ff2bc8bab180273b77e7ab3e8a62cca51 (diff) | |
fbdev: add mutex for fb_mmap locking
Add a mutex to avoid a circular locking problem between the mm layer
semaphore and fbdev ioctl mutex through the fb_mmap() call.
Also, add mutex to all places where smem_start and smem_len fields change
so the mutex inside the fb_mmap() is actually used. Changing of these
fields before calling the framebuffer_register() are not mutexed.
This is 2.6.31 material. It removes one lockdep (fb_mmap() and
register_framebuffer()) but there is still another one (fb_release() and
register_framebuffer()). It also cleans up handling of the smem_start and
smem_len fields used by mutexed section of the fb_mmap().
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video/matrox/matroxfb_base.c')
| -rw-r--r-- | drivers/video/matrox/matroxfb_base.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/video/matrox/matroxfb_base.c b/drivers/video/matrox/matroxfb_base.c index 8e7a275df50..59c3a2e1491 100644 --- a/drivers/video/matrox/matroxfb_base.c +++ b/drivers/video/matrox/matroxfb_base.c @@ -724,8 +724,10 @@ static void matroxfb_update_fix(WPMINFO2) struct fb_fix_screeninfo *fix = &ACCESS_FBINFO(fbcon).fix; DBG(__func__) + mutex_lock(&ACCESS_FBINFO(fbcon).mm_lock); fix->smem_start = ACCESS_FBINFO(video.base) + ACCESS_FBINFO(curr.ydstorg.bytes); fix->smem_len = ACCESS_FBINFO(video.len_usable) - ACCESS_FBINFO(curr.ydstorg.bytes); + mutex_unlock(&ACCESS_FBINFO(fbcon).mm_lock); } static int matroxfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) @@ -2081,6 +2083,7 @@ static int matroxfb_probe(struct pci_dev* pdev, const struct pci_device_id* dumm spin_lock_init(&ACCESS_FBINFO(lock.accel)); init_rwsem(&ACCESS_FBINFO(crtc2.lock)); init_rwsem(&ACCESS_FBINFO(altout.lock)); + mutex_init(&ACCESS_FBINFO(fbcon).mm_lock); ACCESS_FBINFO(irq_flags) = 0; init_waitqueue_head(&ACCESS_FBINFO(crtc1.vsync.wait)); init_waitqueue_head(&ACCESS_FBINFO(crtc2.vsync.wait)); |