media: core: Free range of buffers

Improve __vb2_queue_free() and __vb2_free_mem() to free
range of buffers and not only the last few buffers.
Introduce starting index to be flexible on range and change the loops
according to this parameter.

Signed-off-by: Benjamin Gaignard <[e-mail]>
Acked-by: Mauro Carvalho Chehab <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

drivers/media/common/videobuf2/videobuf2-core.c

···
 }
 
 /*
- * __vb2_free_mem() - release all video buffer memory for a given queue
+ * __vb2_free_mem() - release video buffer memory for a given range of
+ * buffers in a given queue
  */
-static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
+static void __vb2_free_mem(struct vb2_queue *q, unsigned int start, unsigned int count)
 {
-	unsigned int buffer;
+	unsigned int i;
 	struct vb2_buffer *vb;
-	unsigned int q_num_buffers = vb2_get_num_buffers(q);
 
-	for (buffer = q_num_buffers - buffers; buffer < q_num_buffers;
-	     ++buffer) {
-		vb = vb2_get_buffer(q, buffer);
+	for (i = start; i < start + count; i++) {
+		vb = vb2_get_buffer(q, i);
 		if (!vb)
 			continue;
 
···
 }
 
 /*
- * __vb2_queue_free() - free buffers at the end of the queue - video memory and
+ * __vb2_queue_free() - free @count buffers from @start index of the queue - video memory and
  * related information, if no buffers are left return the queue to an
  * uninitialized state. Might be called even if the queue has already been freed.
  */
-static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
+static void __vb2_queue_free(struct vb2_queue *q, unsigned int start, unsigned int count)
 {
-	unsigned int buffer;
-	unsigned int q_num_buffers = vb2_get_num_buffers(q);
+	unsigned int i;
 
 	lockdep_assert_held(&q->mmap_lock);
 
 	/* Call driver-provided cleanup function for each buffer, if provided */
-	for (buffer = q_num_buffers - buffers; buffer < q_num_buffers;
-	     ++buffer) {
-		struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
+	for (i = start; i < start + count; i++) {
+		struct vb2_buffer *vb = vb2_get_buffer(q, i);
 
 		if (vb && vb->planes[0].mem_priv)
 			call_void_vb_qop(vb, buf_cleanup, vb);
 	}
 
 	/* Release video buffer memory */
-	__vb2_free_mem(q, buffers);
+	__vb2_free_mem(q, start, count);
 
 #ifdef CONFIG_VIDEO_ADV_DEBUG
 	/*
 	 * Check that all the calls were balanced during the life-time of this
 	 * queue. If not then dump the counters to the kernel log.
 	 */
-	if (q_num_buffers) {
+	if (vb2_get_num_buffers(q)) {
 		bool unbalanced = q->cnt_start_streaming != q->cnt_stop_streaming ||
 				  q->cnt_prepare_streaming != q->cnt_unprepare_streaming ||
 				  q->cnt_wait_prepare != q->cnt_wait_finish;
···
 		q->cnt_stop_streaming = 0;
 		q->cnt_unprepare_streaming = 0;
 	}
-	for (buffer = 0; buffer < vb2_get_num_buffers(q); buffer++) {
-		struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
+	for (i = start; i < start + count; i++) {
+		struct vb2_buffer *vb = vb2_get_buffer(q, i);
 		bool unbalanced;
 
 		if (!vb)
···
 
 		if (unbalanced) {
 			pr_info("unbalanced counters for queue %p, buffer %d:\n",
-				q, buffer);
+				q, i);
 			if (vb->cnt_buf_init != vb->cnt_buf_cleanup)
 				pr_info("     buf_init: %u buf_cleanup: %u\n",
 					vb->cnt_buf_init, vb->cnt_buf_cleanup);
···
 #endif
 
 	/* Free vb2 buffers */
-	for (buffer = q_num_buffers - buffers; buffer < q_num_buffers;
-	     ++buffer) {
-		struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
+	for (i = start; i < start + count; i++) {
+		struct vb2_buffer *vb = vb2_get_buffer(q, i);
 
 		if (!vb)
 			continue;
···
 static bool __buffers_in_use(struct vb2_queue *q)
 {
 	unsigned int buffer;
-	for (buffer = 0; buffer < vb2_get_num_buffers(q); ++buffer) {
+	for (buffer = 0; buffer < q->max_num_buffers; ++buffer) {
 		struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
 
 		if (!vb)
···
 		 * queued without ever calling STREAMON.
 		 */
 		__vb2_queue_cancel(q);
-		__vb2_queue_free(q, q_num_bufs);
+		__vb2_queue_free(q, 0, q->max_num_buffers);
 		mutex_unlock(&q->mmap_lock);
 
 		q->is_busy = 0;
···
 		 * from already queued buffers and it will reset q->memory to
 		 * VB2_MEMORY_UNKNOWN.
 		 */
-		__vb2_queue_free(q, allocated_buffers);
+		__vb2_queue_free(q, first_index, allocated_buffers);
 		mutex_unlock(&q->mmap_lock);
 		return ret;
 	}
···
 		 * from already queued buffers and it will reset q->memory to
 		 * VB2_MEMORY_UNKNOWN.
 		 */
-		__vb2_queue_free(q, allocated_buffers);
+		__vb2_queue_free(q, *first_index, allocated_buffers);
 		mutex_unlock(&q->mmap_lock);
 		return -ENOMEM;
 	}
···
 		 * Forcefully reclaim buffers if the driver did not
 		 * correctly return them to vb2.
 		 */
-		for (i = 0; i < vb2_get_num_buffers(q); ++i) {
+		for (i = 0; i < q->max_num_buffers; ++i) {
 			vb = vb2_get_buffer(q, i);
 
 			if (!vb)
···
 	 * to vb2 in stop_streaming().
 	 */
 	if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
-		for (i = 0; i < vb2_get_num_buffers(q); i++) {
+		for (i = 0; i < q->max_num_buffers; i++) {
 			struct vb2_buffer *vb = vb2_get_buffer(q, i);
 
 			if (!vb)
···
 	 * call to __fill_user_buffer() after buf_finish(). That order can't
 	 * be changed, so we can't move the buf_finish() to __vb2_dqbuf().
 	 */
-	for (i = 0; i < vb2_get_num_buffers(q); i++) {
+	for (i = 0; i < q->max_num_buffers; i++) {
 		struct vb2_buffer *vb;
 		struct media_request *req;
 
···
 	__vb2_cleanup_fileio(q);
 	__vb2_queue_cancel(q);
 	mutex_lock(&q->mmap_lock);
-	__vb2_queue_free(q, vb2_get_num_buffers(q));
+	__vb2_queue_free(q, 0, q->max_num_buffers);
 	vb2_core_free_buffers_storage(q);
 	q->is_busy = 0;
 	mutex_unlock(&q->mmap_lock);