linux-kernel - [PATCH v3 02/11] media: videobuf2: Use Xarray instead of static buffers array

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Message-Id: <20230622131349.144160-3-benjamin.gaignard@collabora.com>
Date:   Thu, 22 Jun 2023 15:13:40 +0200
From:   Benjamin Gaignard <benjamin.gaignard@...labora.com>
To:     mchehab@...nel.org, tfiga@...omium.org, m.szyprowski@...sung.com,
        ming.qian@....com, ezequiel@...guardiasur.com.ar,
        p.zabel@...gutronix.de, gregkh@...uxfoundation.org,
        hverkuil-cisco@...all.nl, nicolas.dufresne@...labora.com
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
        linux-rockchip@...ts.infradead.org, linux-staging@...ts.linux.dev,
        kernel@...labora.com,
        Benjamin Gaignard <benjamin.gaignard@...labora.com>
Subject: [PATCH v3 02/11] media: videobuf2: Use Xarray instead of static buffers array

Instead of a static array change bufs to a dynamically allocated array.
This will allow to store more video buffers if needed.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@...labora.com>
---
 .../media/common/videobuf2/videobuf2-core.c   | 38 +++++++++++--------
 include/media/videobuf2-core.h                |  6 +--
 2 files changed, 25 insertions(+), 19 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 42fd3984c2bc..f1ff7af34a9f 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -409,18 +409,24 @@ static void init_buffer_cache_hints(struct vb2_queue *q, struct vb2_buffer *vb)
  * vb2_queue_add_buffer() - add a buffer to a queue
  * @q:	pointer to &struct vb2_queue with videobuf2 queue.
  * @vb:	pointer to &struct vb2_buffer to be added to the queue.
- * @index: index where add vb2_buffer in the queue
  */
-static bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, int index)
+static bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb)
 {
-	if (index < VB2_MAX_FRAME && !q->bufs[index]) {
-		q->bufs[index] = vb;
-		vb->index = index;
-		vb->vb2_queue = q;
-		return true;
-	}
+	struct xa_limit range = {
+		.max = UINT_MAX,
+		.min = q->num_buffers,
+	};
+	u32 index;
+	int ret;
 
-	return false;
+	ret = xa_alloc(&q->bufs, &index, vb, range, GFP_KERNEL);
+	if (ret)
+		return false;
+
+	vb->index = index;
+	vb->vb2_queue = q;
+
+	return true;
 }
 
 /**
@@ -430,10 +436,8 @@ static bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, int
  */
 static void vb2_queue_remove_buffer(struct vb2_queue *q, struct vb2_buffer *vb)
 {
-	if (vb->index < VB2_MAX_FRAME) {
-		q->bufs[vb->index] = NULL;
-		vb->vb2_queue = NULL;
-	}
+	xa_erase(&q->bufs, vb->index);
+	vb->vb2_queue = NULL;
 }
 
 /*
@@ -474,7 +478,7 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
 		}
 		call_void_bufop(q, init_buffer, vb);
 
-		if (!vb2_queue_add_buffer(q, vb, q->num_buffers + buffer)) {
+		if (!vb2_queue_add_buffer(q, vb)) {
 			dprintk(q, 1, "failed adding buffer %d to queue\n", buffer);
 			kfree(vb);
 			break;
@@ -930,7 +934,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 	}
 
 	mutex_lock(&q->mmap_lock);
-	q->num_buffers = allocated_buffers;
+	q->num_buffers += allocated_buffers;
 
 	if (ret < 0) {
 		/*
@@ -2547,6 +2551,9 @@ int vb2_core_queue_init(struct vb2_queue *q)
 	mutex_init(&q->mmap_lock);
 	init_waitqueue_head(&q->done_wq);
 
+	xa_init_flags(&q->bufs, XA_FLAGS_ALLOC);
+	q->num_buffers = 0;
+
 	q->memory = VB2_MEMORY_UNKNOWN;
 
 	if (q->buf_struct_size == 0)
@@ -2574,6 +2581,7 @@ void vb2_core_queue_release(struct vb2_queue *q)
 	mutex_lock(&q->mmap_lock);
 	__vb2_queue_free(q, q->num_buffers);
 	mutex_unlock(&q->mmap_lock);
+	xa_destroy(&q->bufs);
 }
 EXPORT_SYMBOL_GPL(vb2_core_queue_release);
 
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 4b6a9d2ea372..77921cf894ef 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -619,7 +619,7 @@ struct vb2_queue {
 	struct mutex			mmap_lock;
 	unsigned int			memory;
 	enum dma_data_direction		dma_dir;
-	struct vb2_buffer		*bufs[VB2_MAX_FRAME];
+	struct xarray			bufs;
 	unsigned int			num_buffers;
 
 	struct list_head		queued_list;
@@ -1239,9 +1239,7 @@ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
 static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
 						unsigned int index)
 {
-	if (index < q->num_buffers)
-		return q->bufs[index];
-	return NULL;
+	return xa_load(&q->bufs, index);
 }
 
 /*
-- 
2.39.2