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authorKrzysztof Helt <krzysztof.h1@wp.pl>2009-06-30 11:41:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-30 18:56:00 -0700
commit537a1bf059fa312355696fa6db80726e655e7f17 (patch)
tree4f5b3c6917311cfefad21eaf3dd92978334282de /drivers/video/atafb.c
parent70d6027ff2bc8bab180273b77e7ab3e8a62cca51 (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/atafb.c')
-rw-r--r--drivers/video/atafb.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/video/atafb.c b/drivers/video/atafb.c
index 018850c116c..497ff8af03e 100644
--- a/drivers/video/atafb.c
+++ b/drivers/video/atafb.c
@@ -2414,7 +2414,10 @@ static int atafb_get_fix(struct fb_fix_screeninfo *fix, struct fb_info *info)
if (err)
return err;
memset(fix, 0, sizeof(struct fb_fix_screeninfo));
- return fbhw->encode_fix(fix, &par);
+ mutex_lock(&info->mm_lock);
+ err = fbhw->encode_fix(fix, &par);
+ mutex_unlock(&info->mm_lock);
+ return err;
}
static int atafb_get_var(struct fb_var_screeninfo *var, struct fb_info *info)
@@ -2743,7 +2746,9 @@ static int atafb_set_par(struct fb_info *info)
/* Decode wanted screen parameters */
fbhw->decode_var(&info->var, par);
+ mutex_lock(&info->mm_lock);
fbhw->encode_fix(&info->fix, par);
+ mutex_unlock(&info->mm_lock);
/* Set new videomode */
ata_set_par(par);