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/w100fb.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/w100fb.c')
| -rw-r--r-- | drivers/video/w100fb.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/video/w100fb.c b/drivers/video/w100fb.c index d0674f1e3f10..8a141c2c637b 100644 --- a/drivers/video/w100fb.c +++ b/drivers/video/w100fb.c @@ -523,6 +523,7 @@ static int w100fb_set_par(struct fb_info *info) info->fix.ywrapstep = 0; info->fix.line_length = par->xres * BITS_PER_PIXEL / 8; + mutex_lock(&info->mm_lock); if ((par->xres*par->yres*BITS_PER_PIXEL/8) > (MEM_INT_SIZE+1)) { par->extmem_active = 1; info->fix.smem_len = par->mach->mem->size+1; @@ -530,6 +531,7 @@ static int w100fb_set_par(struct fb_info *info) par->extmem_active = 0; info->fix.smem_len = MEM_INT_SIZE+1; } + mutex_unlock(&info->mm_lock); w100fb_activate_var(par); } |