diff options
| author | Krzysztof Helt <krzysztof.h1@wp.pl> | 2009-06-30 22:41:29 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-07-01 05:56:00 +0400 |
| commit | 537a1bf059fa312355696fa6db80726e655e7f17 (patch) | |
| tree | 4f5b3c6917311cfefad21eaf3dd92978334282de /drivers/video/fbmem.c | |
| parent | 70d6027ff2bc8bab180273b77e7ab3e8a62cca51 (diff) | |
| download | linux-537a1bf059fa312355696fa6db80726e655e7f17.tar.xz | |
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/fbmem.c')
| -rw-r--r-- | drivers/video/fbmem.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c index f8a09bf8d0cd..53ea05645ff8 100644 --- a/drivers/video/fbmem.c +++ b/drivers/video/fbmem.c @@ -1310,8 +1310,6 @@ static long fb_compat_ioctl(struct file *file, unsigned int cmd, static int fb_mmap(struct file *file, struct vm_area_struct * vma) -__acquires(&info->lock) -__releases(&info->lock) { int fbidx = iminor(file->f_path.dentry->d_inode); struct fb_info *info = registered_fb[fbidx]; @@ -1325,16 +1323,14 @@ __releases(&info->lock) off = vma->vm_pgoff << PAGE_SHIFT; if (!fb) return -ENODEV; + mutex_lock(&info->mm_lock); if (fb->fb_mmap) { int res; - mutex_lock(&info->lock); res = fb->fb_mmap(info, vma); - mutex_unlock(&info->lock); + mutex_unlock(&info->mm_lock); return res; } - mutex_lock(&info->lock); - /* frame buffer memory */ start = info->fix.smem_start; len = PAGE_ALIGN((start & ~PAGE_MASK) + info->fix.smem_len); @@ -1342,13 +1338,13 @@ __releases(&info->lock) /* memory mapped io */ off -= len; if (info->var.accel_flags) { - mutex_unlock(&info->lock); + mutex_unlock(&info->mm_lock); return -EINVAL; } start = info->fix.mmio_start; len = PAGE_ALIGN((start & ~PAGE_MASK) + info->fix.mmio_len); } - mutex_unlock(&info->lock); + mutex_unlock(&info->mm_lock); start &= PAGE_MASK; if ((vma->vm_end - vma->vm_start + off) > len) return -EINVAL; @@ -1518,6 +1514,7 @@ register_framebuffer(struct fb_info *fb_info) break; fb_info->node = i; mutex_init(&fb_info->lock); + mutex_init(&fb_info->mm_lock); fb_info->dev = device_create(fb_class, fb_info->device, MKDEV(FB_MAJOR, i), NULL, "fb%d", i); |