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Message-Id: <20240119094944.26763-5-benjamin.gaignard@collabora.com>
Date: Fri, 19 Jan 2024 10:49:40 +0100
From: Benjamin Gaignard <benjamin.gaignard@...labora.com>
To: hverkuil@...all.nl,
mchehab@...nel.org
Cc: linux-kernel@...r.kernel.org,
linux-media@...r.kernel.org,
kernel@...labora.com,
Benjamin Gaignard <benjamin.gaignard@...labora.com>
Subject: [PATCH v17 4/8] media: core: Add bitmap manage bufs array entries
Add a bitmap field to know which of bufs array entries are
used or not.
Remove no more used num_buffers field from queue structure.
Use bitmap_find_next_zero_area() to find the first possible
range when creating new buffers to fill the gaps.
If no suitable range is found try to allocate less buffers
than requested.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@...labora.com>
---
version 17:
- allow to allocate less buffers than requested in __vb2_queue_alloc()
when using bitmap.
- add vb2_core_allocated_queue_buffers_storage() and
vb2_core_free_queue_buffers_storage() to avoid duplicate code.
.../media/common/videobuf2/videobuf2-core.c | 71 ++++++++++++++-----
include/media/videobuf2-core.h | 18 +++--
2 files changed, 64 insertions(+), 25 deletions(-)
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index fd5ac2845018..45cbdfaf72b5 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -421,11 +421,12 @@ static void init_buffer_cache_hints(struct vb2_queue *q, struct vb2_buffer *vb)
*/
static void vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, unsigned int index)
{
- WARN_ON(index >= q->max_num_buffers || q->bufs[index] || vb->vb2_queue);
+ WARN_ON(index >= q->max_num_buffers || test_bit(index, q->bufs_bitmap) || vb->vb2_queue);
q->bufs[index] = vb;
vb->index = index;
vb->vb2_queue = q;
+ set_bit(index, q->bufs_bitmap);
}
/**
@@ -434,6 +435,7 @@ static void vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, uns
*/
static void vb2_queue_remove_buffer(struct vb2_buffer *vb)
{
+ clear_bit(vb->index, vb->vb2_queue->bufs_bitmap);
vb->vb2_queue->bufs[vb->index] = NULL;
vb->vb2_queue = NULL;
}
@@ -452,9 +454,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
const unsigned int plane_sizes[VB2_MAX_PLANES],
unsigned int *first_index)
{
- unsigned int q_num_buffers = vb2_get_num_buffers(q);
unsigned int buffer, plane;
struct vb2_buffer *vb;
+ unsigned long index = 0;
int ret;
/*
@@ -462,9 +464,25 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
* in the queue is below q->max_num_buffers
*/
num_buffers = min_t(unsigned int, num_buffers,
- q->max_num_buffers - q_num_buffers);
+ q->max_num_buffers - vb2_get_num_buffers(q));
+
+again:
+ index = bitmap_find_next_zero_area(q->bufs_bitmap, q->max_num_buffers,
+ 0, num_buffers, 0);
+
+ /* Try to find free space for less buffers */
+ if (index >= q->max_num_buffers && num_buffers) {
+ num_buffers--;
+ goto again;
+ }
- *first_index = q_num_buffers;
+ /* If there is no space left to allocate buffers return 0 to indicate the error */
+ if (index >= q->max_num_buffers) {
+ *first_index = 0;
+ return 0;
+ }
+
+ *first_index = index;
for (buffer = 0; buffer < num_buffers; ++buffer) {
/* Allocate vb2 buffer structures */
@@ -484,7 +502,7 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
vb->planes[plane].min_length = plane_sizes[plane];
}
- vb2_queue_add_buffer(q, vb, q_num_buffers + buffer);
+ vb2_queue_add_buffer(q, vb, index++);
call_void_bufop(q, init_buffer, vb);
/* Allocate video buffer memory for the MMAP type */
@@ -664,7 +682,6 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
kfree(vb);
}
- q->num_buffers -= buffers;
if (!vb2_get_num_buffers(q)) {
q->memory = VB2_MEMORY_UNKNOWN;
INIT_LIST_HEAD(&q->queued_list);
@@ -818,6 +835,32 @@ static bool verify_coherency_flags(struct vb2_queue *q, bool non_coherent_mem)
return true;
}
+static int vb2_core_allocated_queue_buffers_storage(struct vb2_queue *q)
+{
+ if (!q->bufs)
+ q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);
+ if (!q->bufs)
+ return -ENOMEM;
+
+ if (!q->bufs_bitmap)
+ q->bufs_bitmap = bitmap_zalloc(q->max_num_buffers, GFP_KERNEL);
+ if (!q->bufs_bitmap) {
+ kfree(q->bufs);
+ q->bufs = NULL;
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void vb2_core_free_queue_buffers_storage(struct vb2_queue *q)
+{
+ kfree(q->bufs);
+ q->bufs = NULL;
+ bitmap_free(q->bufs_bitmap);
+ q->bufs_bitmap = NULL;
+}
+
int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
unsigned int flags, unsigned int *count)
{
@@ -878,10 +921,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
* in the queue_setup op.
*/
mutex_lock(&q->mmap_lock);
- if (!q->bufs)
- q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);
- if (!q->bufs)
- ret = -ENOMEM;
+ ret = vb2_core_allocated_queue_buffers_storage(q);
q->memory = memory;
mutex_unlock(&q->mmap_lock);
if (ret)
@@ -953,7 +993,6 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
}
mutex_lock(&q->mmap_lock);
- q->num_buffers = allocated_buffers;
if (ret < 0) {
/*
@@ -980,6 +1019,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
mutex_lock(&q->mmap_lock);
q->memory = VB2_MEMORY_UNKNOWN;
mutex_unlock(&q->mmap_lock);
+ vb2_core_free_queue_buffers_storage(q);
return ret;
}
EXPORT_SYMBOL_GPL(vb2_core_reqbufs);
@@ -1013,11 +1053,8 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
* value in the queue_setup op.
*/
mutex_lock(&q->mmap_lock);
+ ret = vb2_core_allocated_queue_buffers_storage(q);
q->memory = memory;
- if (!q->bufs)
- q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);
- if (!q->bufs)
- ret = -ENOMEM;
mutex_unlock(&q->mmap_lock);
if (ret)
return ret;
@@ -1080,7 +1117,6 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
}
mutex_lock(&q->mmap_lock);
- q->num_buffers += allocated_buffers;
if (ret < 0) {
/*
@@ -2579,8 +2615,7 @@ void vb2_core_queue_release(struct vb2_queue *q)
__vb2_queue_cancel(q);
mutex_lock(&q->mmap_lock);
__vb2_queue_free(q, vb2_get_num_buffers(q));
- kfree(q->bufs);
- q->bufs = NULL;
+ vb2_core_free_queue_buffers_storage(q);
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 e29ff77814d3..8647eee348bd 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -346,8 +346,8 @@ struct vb2_buffer {
* describes the requested number of planes and sizes\[\]
* contains the requested plane sizes. In this case
* \*num_buffers are being allocated additionally to
- * q->num_buffers. If either \*num_planes or the requested
- * sizes are invalid callback must return %-EINVAL.
+ * the buffers already allocated. If either \*num_planes
+ * or the requested sizes are invalid callback must return %-EINVAL.
* @wait_prepare: release any locks taken while calling vb2 functions;
* it is called before an ioctl needs to wait for a new
* buffer to arrive; required to avoid a deadlock in
@@ -571,8 +571,9 @@ struct vb2_buf_ops {
* @mmap_lock: private mutex used when buffers are allocated/freed/mmapped
* @memory: current memory type used
* @dma_dir: DMA mapping direction.
- * @bufs: videobuf2 buffer structures
- * @num_buffers: number of allocated/used buffers
+ * @bufs: videobuf2 buffer structures. If it is non-NULL then
+ * bufs_bitmap is also non-NULL.
+ * @bufs_bitmap: bitmap tracking whether each bufs[] entry is used
* @max_num_buffers: upper limit of number of allocated/used buffers.
* If set to 0 v4l2 core will change it VB2_MAX_FRAME
* for backward compatibility.
@@ -639,7 +640,7 @@ struct vb2_queue {
unsigned int memory;
enum dma_data_direction dma_dir;
struct vb2_buffer **bufs;
- unsigned int num_buffers;
+ unsigned long *bufs_bitmap;
unsigned int max_num_buffers;
struct list_head queued_list;
@@ -1168,7 +1169,10 @@ static inline bool vb2_fileio_is_active(struct vb2_queue *q)
*/
static inline unsigned int vb2_get_num_buffers(struct vb2_queue *q)
{
- return q->num_buffers;
+ if (q->bufs_bitmap)
+ return bitmap_weight(q->bufs_bitmap, q->max_num_buffers);
+
+ return 0;
}
/**
@@ -1277,7 +1281,7 @@ static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
if (index >= q->max_num_buffers)
return NULL;
- if (index < q->num_buffers)
+ if (test_bit(index, q->bufs_bitmap))
return q->bufs[index];
return NULL;
}
--
2.40.1
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