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/atafb.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers/video/atafb.c') 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); -- cgit v1.2.3-70-g09d2 From feaa61e49b126c2206051a234b8f14ccc75b9f61 Mon Sep 17 00:00:00 2001 From: Krzysztof Helt Date: Tue, 7 Jul 2009 19:15:16 +0200 Subject: atafb: fix regression with uninitalized fb_info->mm_lock mutex Remove redundant locking of the fb_info->mm_lock mutex before the frambuffer is registered. This fixes a problem with uninitialized the fb_info->mm_lock mutex introduced by the commit 537a1bf059f " fbdev: add mutex for fb_mmap locking" Signed-off-by: Krzysztof Helt Signed-off-by: Linus Torvalds --- drivers/video/atafb.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/video/atafb.c') diff --git a/drivers/video/atafb.c b/drivers/video/atafb.c index 497ff8af03e..8cd279be74e 100644 --- a/drivers/video/atafb.c +++ b/drivers/video/atafb.c @@ -2405,6 +2405,9 @@ static int do_fb_set_var(struct fb_var_screeninfo *var, int isactive) return 0; } +/* fbhw->encode_fix() must be called with fb_info->mm_lock held + * if it is called after the register_framebuffer() - not a case here + */ static int atafb_get_fix(struct fb_fix_screeninfo *fix, struct fb_info *info) { struct atafb_par par; @@ -2414,9 +2417,7 @@ 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)); - mutex_lock(&info->mm_lock); err = fbhw->encode_fix(fix, &par); - mutex_unlock(&info->mm_lock); return err; } -- cgit v1.2.3-70-g09d2