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authorArjan van de Ven <arjan@linux.intel.com>2008-05-20 09:53:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-05-20 10:12:26 -0700
commit81b2dbcad86732ffc02bad87aa25c4651199fc77 (patch)
tree6c956c561fbaaa7e04ef612695bf5d3d0b5faef2
parentbabd90b274e6b43a7dc7bb08562bf566cbabdbf8 (diff)
Fix a deadlock in the bttv driver
vidiocgmbuf() does this: mutex_lock(&fh->cap.vb_lock); retval = videobuf_mmap_setup(&fh->cap, gbuffers, gbufsize, V4L2_MEMORY_MMAP); and videobuf_mmap_setup() then just does mutex_lock(&q->vb_lock); ret = __videobuf_mmap_setup(q, bcount, bsize, memory); mutex_unlock(&q->vb_lock); which is an obvious double-take deadlock. This patch fixes this by having vidiocgmbuf() just call the __videobuf_mmap_setup function instead. Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org> Reported-by: Koos Vriezen <koos.vriezen@gmail.com> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/media/video/bt8xx/bttv-driver.c2
-rw-r--r--drivers/media/video/videobuf-core.c3
-rw-r--r--include/media/videobuf-core.h3
3 files changed, 6 insertions, 2 deletions
diff --git a/drivers/media/video/bt8xx/bttv-driver.c b/drivers/media/video/bt8xx/bttv-driver.c
index 2ca3e9cfb2b..0165aac533b 100644
--- a/drivers/media/video/bt8xx/bttv-driver.c
+++ b/drivers/media/video/bt8xx/bttv-driver.c
@@ -2613,7 +2613,7 @@ static int vidiocgmbuf(struct file *file, void *priv, struct video_mbuf *mbuf)
struct bttv_fh *fh = priv;
mutex_lock(&fh->cap.vb_lock);
- retval = videobuf_mmap_setup(&fh->cap, gbuffers, gbufsize,
+ retval = __videobuf_mmap_setup(&fh->cap, gbuffers, gbufsize,
V4L2_MEMORY_MMAP);
if (retval < 0) {
mutex_unlock(&fh->cap.vb_lock);
diff --git a/drivers/media/video/videobuf-core.c b/drivers/media/video/videobuf-core.c
index 982f4463896..0a88c44ace0 100644
--- a/drivers/media/video/videobuf-core.c
+++ b/drivers/media/video/videobuf-core.c
@@ -331,7 +331,7 @@ int videobuf_mmap_free(struct videobuf_queue *q)
}
/* Locking: Caller holds q->vb_lock */
-static int __videobuf_mmap_setup(struct videobuf_queue *q,
+int __videobuf_mmap_setup(struct videobuf_queue *q,
unsigned int bcount, unsigned int bsize,
enum v4l2_memory memory)
{
@@ -1129,6 +1129,7 @@ EXPORT_SYMBOL_GPL(videobuf_read_stream);
EXPORT_SYMBOL_GPL(videobuf_read_one);
EXPORT_SYMBOL_GPL(videobuf_poll_stream);
+EXPORT_SYMBOL_GPL(__videobuf_mmap_setup);
EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
EXPORT_SYMBOL_GPL(videobuf_mmap_free);
EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);
diff --git a/include/media/videobuf-core.h b/include/media/videobuf-core.h
index 5b39a22533f..874f1340d04 100644
--- a/include/media/videobuf-core.h
+++ b/include/media/videobuf-core.h
@@ -237,6 +237,9 @@ unsigned int videobuf_poll_stream(struct file *file,
int videobuf_mmap_setup(struct videobuf_queue *q,
unsigned int bcount, unsigned int bsize,
enum v4l2_memory memory);
+int __videobuf_mmap_setup(struct videobuf_queue *q,
+ unsigned int bcount, unsigned int bsize,
+ enum v4l2_memory memory);
int videobuf_mmap_free(struct videobuf_queue *q);
int videobuf_mmap_mapper(struct videobuf_queue *q,
struct vm_area_struct *vma);