From 537a1bf059fa312355696fa6db80726e655e7f17 Mon Sep 17 00:00:00 2001 From: Krzysztof Helt Date: Tue, 30 Jun 2009 11:41:29 -0700 Subject: 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 Cc: Peter Zijlstra Cc: "Rafael J. Wysocki" Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/atmel_lcdfb.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/video/atmel_lcdfb.c') diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c index 5afd64482f5..cb88394ba99 100644 --- a/drivers/video/atmel_lcdfb.c +++ b/drivers/video/atmel_lcdfb.c @@ -270,7 +270,9 @@ static int atmel_lcdfb_alloc_video_memory(struct atmel_lcdfb_info *sinfo) smem_len = (var->xres_virtual * var->yres_virtual * ((var->bits_per_pixel + 7) / 8)); + mutex_lock(&info->mm_lock); info->fix.smem_len = max(smem_len, sinfo->smem_len); + mutex_unlock(&info->mm_lock); info->screen_base = dma_alloc_writecombine(info->device, info->fix.smem_len, (dma_addr_t *)&info->fix.smem_start, GFP_KERNEL); -- cgit v1.2.3