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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/fsl-diu-fb.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/fsl-diu-fb.c')
-rw-r--r--drivers/video/fsl-diu-fb.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index f153c581cbd..0bf2190928d 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);
}
/*