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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/matrox/matroxfb_base.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/matrox/matroxfb_base.c')
-rw-r--r--drivers/video/matrox/matroxfb_base.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/video/matrox/matroxfb_base.c b/drivers/video/matrox/matroxfb_base.c
index 8e7a275df50..59c3a2e1491 100644
--- a/drivers/video/matrox/matroxfb_base.c
+++ b/drivers/video/matrox/matroxfb_base.c
@@ -724,8 +724,10 @@ static void matroxfb_update_fix(WPMINFO2)
struct fb_fix_screeninfo *fix = &ACCESS_FBINFO(fbcon).fix;
DBG(__func__)
+ mutex_lock(&ACCESS_FBINFO(fbcon).mm_lock);
fix->smem_start = ACCESS_FBINFO(video.base) + ACCESS_FBINFO(curr.ydstorg.bytes);
fix->smem_len = ACCESS_FBINFO(video.len_usable) - ACCESS_FBINFO(curr.ydstorg.bytes);
+ mutex_unlock(&ACCESS_FBINFO(fbcon).mm_lock);
}
static int matroxfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
@@ -2081,6 +2083,7 @@ static int matroxfb_probe(struct pci_dev* pdev, const struct pci_device_id* dumm
spin_lock_init(&ACCESS_FBINFO(lock.accel));
init_rwsem(&ACCESS_FBINFO(crtc2.lock));
init_rwsem(&ACCESS_FBINFO(altout.lock));
+ mutex_init(&ACCESS_FBINFO(fbcon).mm_lock);
ACCESS_FBINFO(irq_flags) = 0;
init_waitqueue_head(&ACCESS_FBINFO(crtc1.vsync.wait));
init_waitqueue_head(&ACCESS_FBINFO(crtc2.vsync.wait));