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/fsl-diu-fb.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/fsl-diu-fb.c')
| -rw-r--r-- | drivers/video/fsl-diu-fb.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c index f153c581cbd7..0bf2190928d0 100644 --- a/drivers/video/fsl-diu-fb.c +++ b/drivers/video/fsl-diu-fb.c @@ -750,24 +750,26 @@ static void update_lcdc(struct fb_info *info) static int map_video_memory(struct fb_info *info) { phys_addr_t phys; + u32 smem_len = info->fix.line_length * info->var.yres_virtual; pr_debug("info->var.xres_virtual = %d\n", info->var.xres_virtual); pr_debug("info->var.yres_virtual = %d\n", info->var.yres_virtual); pr_debug("info->fix.line_length = %d\n", info->fix.line_length); + pr_debug("MAP_VIDEO_MEMORY: smem_len = %u\n", smem_len); - info->fix.smem_len = info->fix.line_length * info->var.yres_virtual; - pr_debug("MAP_VIDEO_MEMORY: smem_len = %d\n", info->fix.smem_len); - info->screen_base = fsl_diu_alloc(info->fix.smem_len, &phys); + info->screen_base = fsl_diu_alloc(smem_len, &phys); if (info->screen_base == NULL) { printk(KERN_ERR "Unable to allocate fb memory\n"); return -ENOMEM; } + mutex_lock(&info->mm_lock); info->fix.smem_start = (unsigned long) phys; + info->fix.smem_len = smem_len; + mutex_unlock(&info->mm_lock); info->screen_size = info->fix.smem_len; pr_debug("Allocated fb @ paddr=0x%08lx, size=%d.\n", - info->fix.smem_start, - info->fix.smem_len); + info->fix.smem_start, info->fix.smem_len); pr_debug("screen base %p\n", info->screen_base); return 0; @@ -776,9 +778,11 @@ static int map_video_memory(struct fb_info *info) static void unmap_video_memory(struct fb_info *info) { fsl_diu_free(info->screen_base, info->fix.smem_len); + mutex_lock(&info->mm_lock); info->screen_base = NULL; info->fix.smem_start = 0; info->fix.smem_len = 0; + mutex_unlock(&info->mm_lock); } /* |