media: videobuf2: Update vb2_is_busy() logic

Do not rely on the number of allocated buffers to know if the
queue is busy but on a flag set when at least one buffer has been allocated
by REQBUFS or CREATE_BUFS ioctl.
The flag is reset when REQBUFS is called with count = 0 or the file
handle is closed.
This is needed because remove buffers feature will be able to remove
all the buffers from a queue while streaming so relying on the number
of allocated buffers in the queue won't be possible.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index b6bf8f232f4880ffcd1f7ff0bd00ddb0bbebccb9..d8b3c04cb3b5de890fae4db9555719103a35558a 100644 (file)
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -854,6 +854,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
                __vb2_queue_free(q, q_num_bufs);
                mutex_unlock(&q->mmap_lock);
 
+               q->is_busy = 0;
                /*
                 * In case of REQBUFS(0) return immediately without calling
                 * driver's queue_setup() callback and allocating resources.
@@ -966,6 +967,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
         */
        *count = allocated_buffers;
        q->waiting_for_buffers = !q->is_output;
+       q->is_busy = 1;
 
        return 0;
 
@@ -1091,6 +1093,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
         * to the userspace.
         */
        *count = allocated_buffers;
+       q->is_busy = 1;
 
        return 0;
 
@@ -2555,6 +2558,7 @@ void vb2_core_queue_release(struct vb2_queue *q)
        __vb2_queue_free(q, vb2_get_num_buffers(q));
        kfree(q->bufs);
        q->bufs = NULL;
+       q->is_busy = 0;
        mutex_unlock(&q->mmap_lock);
 }
 EXPORT_SYMBOL_GPL(vb2_core_queue_release);

diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 8b86996b2719309f18dd87c436a500c222c34751..667bf9ee1101b8268817161960db6dbab27402d1 100644 (file)
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -582,6 +582,7 @@ struct vb2_buf_ops {
  *             released. Used to prevent destroying the queue by other threads.
  * @is_multiplanar: set if buffer type is multiplanar
  * @is_output: set if buffer type is output
+ * @is_busy:   set if at least one buffer has been allocated at some time.
  * @copy_timestamp: set if vb2-core should set timestamps
  * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
  *             last decoded buffer was already dequeued. Set for capture queues
@@ -647,6 +648,7 @@ struct vb2_queue {
        unsigned int                    waiting_in_dqbuf:1;
        unsigned int                    is_multiplanar:1;
        unsigned int                    is_output:1;
+       unsigned int                    is_busy:1;
        unsigned int                    copy_timestamp:1;
        unsigned int                    last_buffer_dequeued:1;
 
@@ -1166,7 +1168,7 @@ static inline unsigned int vb2_get_num_buffers(struct vb2_queue *q)
  */
 static inline bool vb2_is_busy(struct vb2_queue *q)
 {
-       return vb2_get_num_buffers(q) > 0;
+       return !!q->is_busy;
 }
 
 /**