Commit 81b2dbca authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Linus Torvalds

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: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
Reported-by: default avatarKoos Vriezen <koos.vriezen@gmail.com>
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent babd90b2
...@@ -2613,7 +2613,7 @@ static int vidiocgmbuf(struct file *file, void *priv, struct video_mbuf *mbuf) ...@@ -2613,7 +2613,7 @@ static int vidiocgmbuf(struct file *file, void *priv, struct video_mbuf *mbuf)
struct bttv_fh *fh = priv; struct bttv_fh *fh = priv;
mutex_lock(&fh->cap.vb_lock); 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); V4L2_MEMORY_MMAP);
if (retval < 0) { if (retval < 0) {
mutex_unlock(&fh->cap.vb_lock); mutex_unlock(&fh->cap.vb_lock);
......
...@@ -331,7 +331,7 @@ int videobuf_mmap_free(struct videobuf_queue *q) ...@@ -331,7 +331,7 @@ int videobuf_mmap_free(struct videobuf_queue *q)
} }
/* Locking: Caller holds q->vb_lock */ /* 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, unsigned int bcount, unsigned int bsize,
enum v4l2_memory memory) enum v4l2_memory memory)
{ {
...@@ -1129,6 +1129,7 @@ EXPORT_SYMBOL_GPL(videobuf_read_stream); ...@@ -1129,6 +1129,7 @@ EXPORT_SYMBOL_GPL(videobuf_read_stream);
EXPORT_SYMBOL_GPL(videobuf_read_one); EXPORT_SYMBOL_GPL(videobuf_read_one);
EXPORT_SYMBOL_GPL(videobuf_poll_stream); EXPORT_SYMBOL_GPL(videobuf_poll_stream);
EXPORT_SYMBOL_GPL(__videobuf_mmap_setup);
EXPORT_SYMBOL_GPL(videobuf_mmap_setup); EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
EXPORT_SYMBOL_GPL(videobuf_mmap_free); EXPORT_SYMBOL_GPL(videobuf_mmap_free);
EXPORT_SYMBOL_GPL(videobuf_mmap_mapper); EXPORT_SYMBOL_GPL(videobuf_mmap_mapper);
...@@ -237,6 +237,9 @@ unsigned int videobuf_poll_stream(struct file *file, ...@@ -237,6 +237,9 @@ unsigned int videobuf_poll_stream(struct file *file,
int videobuf_mmap_setup(struct videobuf_queue *q, int videobuf_mmap_setup(struct videobuf_queue *q,
unsigned int bcount, unsigned int bsize, unsigned int bcount, unsigned int bsize,
enum v4l2_memory memory); 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_free(struct videobuf_queue *q);
int videobuf_mmap_mapper(struct videobuf_queue *q, int videobuf_mmap_mapper(struct videobuf_queue *q,
struct vm_area_struct *vma); struct vm_area_struct *vma);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment