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

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
version 9:
- fix compilation issue

 .../media/common/videobuf2/videobuf2-core.c   | 40 ++++++++-----------
 1 file changed, 17 insertions(+), 23 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 4cbc17e8b53e..b9b8a44b378c 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -515,13 +515,12 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
 /*
  * __vb2_free_mem() - release all video buffer memory for 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 = 0;
-	long i = q->max_num_buffers;
+	unsigned int i;
 	struct vb2_buffer *vb;
 
-	for (i = q->max_num_buffers; i >= 0 && buffer < buffers; i--) {
+	for (i = start; i < q->max_num_buffers && i < start + count; i++) {
 		vb = vb2_get_buffer(q, i);
 		if (!vb)
 			continue;
@@ -533,36 +532,32 @@ static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
 			__vb2_buf_dmabuf_put(vb);
 		else
 			__vb2_buf_userptr_put(vb);
-		buffer++;
 	}
 }
 
 /*
- * __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;
-	long i = q->max_num_buffers;
+	unsigned int i;
 
 	lockdep_assert_held(&q->mmap_lock);
 
 	/* Call driver-provided cleanup function for each buffer, if provided */
-	for (i = q->max_num_buffers, buffer = 0; i >= 0 && buffer < buffers; i--) {
+	for (i = start; i < q->max_num_buffers && i < start + count; i++) {
 		struct vb2_buffer *vb = vb2_get_buffer(q, i);
 
 		if (!vb)
 			continue;
-		if (vb->planes[0].mem_priv) {
+		if (vb->planes[0].mem_priv)
 			call_void_vb_qop(vb, buf_cleanup, vb);
-			buffer++;
-		}
 	}
 
 	/* Release video buffer memory */
-	__vb2_free_mem(q, buffers);
+	__vb2_free_mem(q, start, count);
 
 #ifdef CONFIG_VIDEO_ADV_DEBUG
 	/*
@@ -595,8 +590,8 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
 		q->cnt_stop_streaming = 0;
 		q->cnt_unprepare_streaming = 0;
 	}
-	for (buffer = 0; buffer < q->max_num_buffers; buffer++) {
-		struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
+	for (i = 0; i < q->max_num_buffers; i++) {
+		struct vb2_buffer *vb = vb2_get_buffer(q, i);
 		bool unbalanced;
 
 		if (!vb)
@@ -613,7 +608,7 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
 
 		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);
@@ -647,7 +642,7 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
 #endif
 
 	/* Free vb2 buffers */
-	for (i = q->max_num_buffers, buffer = 0; i >= 0 && buffer < buffers; i--) {
+	for (i = start; i < q->max_num_buffers && i < start + count; i++) {
 		struct vb2_buffer *vb = vb2_get_buffer(q, i);
 
 		if (!vb)
@@ -655,7 +650,6 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
 
 		vb2_queue_remove_buffer(vb);
 		kfree(vb);
-		buffer++;
 	}
 
 	if (!vb2_get_num_buffers(q)) {
@@ -849,7 +843,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 		 * queued without ever calling STREAMON.
 		 */
 		__vb2_queue_cancel(q);
-		__vb2_queue_free(q, q_num_bufs);
+		__vb2_queue_free(q, 0, q_num_bufs);
 		mutex_unlock(&q->mmap_lock);
 
 		/*
@@ -959,7 +953,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 		 * 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;
 	}
@@ -1099,7 +1093,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 		 * 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;
 	}
@@ -2565,7 +2559,7 @@ void vb2_core_queue_release(struct vb2_queue *q)
 	__vb2_cleanup_fileio(q);
 	__vb2_queue_cancel(q);
 	mutex_lock(&q->mmap_lock);
-	__vb2_queue_free(q, q->max_num_buffers);
+	__vb2_queue_free(q, 0, q->max_num_buffers);
 	kfree(q->bufs);
 	q->bufs = NULL;
 	bitmap_free(q->bufs_bitmap);
-- 
2.39.2