RE: [EXT] [PATCH v2 3/8] media: videobuf2: Add a module param to limit vb2 queue buffer storage

Add module parameter "max_vb_buffer_per_queue" to be able to limit the
number of vb2 buffers store in queue.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
drivers/media/common/videobuf2/videobuf2-core.c | 15 +++------------
include/media/videobuf2-core.h                  | 11 +++++++++--
2 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c

b/drivers/media/common/videobuf2/videobuf2-core.c
index ae9d72f4d181..f4da917ccf3f 100644

--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c

@@ -34,6 +34,8 @@

static int debug;
module_param(debug, int, 0644);

+module_param(max_vb_buffer_per_queue, ulong, 0644);
+
#define dprintk(q, level, fmt, arg...)                                 \
       do {                                                            \
               if (debug >= level)                                     \

@@ -412,10 +414,6 @@ static int __vb2_queue_alloc(struct vb2_queue *q,

enum vb2_memory memory,
       struct vb2_buffer *vb;
       int ret;

-       /* Ensure that q->num_buffers+num_buffers is below VB2_MAX_FRAME
*/
-       num_buffers = min_t(unsigned int, num_buffers,
-                           VB2_MAX_FRAME - q->num_buffers);
-
       for (buffer = 0; buffer < num_buffers; ++buffer) {
               /* Allocate vb2 buffer structures */
               vb = kzalloc(q->buf_struct_size, GFP_KERNEL); @@ -801,9 +799,7

@@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
       /*
        * Make sure the requested values and current defaults are sane.
        */
-       WARN_ON(q->min_buffers_needed > VB2_MAX_FRAME);
       num_buffers = max_t(unsigned int, *count, q->min_buffers_needed);
-       num_buffers = min_t(unsigned int, num_buffers, VB2_MAX_FRAME);
       memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
       /*
        * Set this now to ensure that drivers see the correct q->memory value

@@ -919,11 +915,6 @@ int vb2_core_create_bufs(struct vb2_queue *q,

enum vb2_memory memory,
       bool no_previous_buffers = !q->num_buffers;
       int ret;

-       if (q->num_buffers == VB2_MAX_FRAME) {
-               dprintk(q, 1, "maximum number of buffers already allocated\n");
-               return -ENOBUFS;
-       }
-
       if (no_previous_buffers) {
               if (q->waiting_in_dqbuf && *count) {
                       dprintk(q, 1, "another dup()ped fd is waiting for a buffer\n");

@@ -948,7 +939,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum

vb2_memory memory,
                       return -EINVAL;
       }

-       num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
+       num_buffers = *count;

       if (requested_planes && requested_sizes) {
               num_planes = requested_planes; diff --git
a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index
397dbf6e61e1..b8b34a993e04 100644

--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h

@@ -12,6 +12,7 @@

#ifndef _MEDIA_VIDEOBUF2_CORE_H
#define _MEDIA_VIDEOBUF2_CORE_H

+#include <linux/minmax.h>
#include <linux/mm_types.h>
#include <linux/mutex.h>
#include <linux/poll.h>

@@ -48,6 +49,8 @@ struct vb2_fileio_data;  struct vb2_threadio_data;  struct

vb2_buffer;

+static size_t max_vb_buffer_per_queue = 1024;
+
/**
 * struct vb2_mem_ops - memory handling/memory allocator operations.
 * @alloc:     allocate video memory and, optionally, allocator private data,

@@ -1268,12 +1271,16 @@ static inline bool vb2_queue_add_buffer(struct

vb2_queue *q, struct vb2_buffer *

       if (vb->index >= q->max_num_bufs) {
               struct vb2_buffer **tmp;
+               int cnt = min(max_vb_buffer_per_queue, q->max_num_bufs *
+ 2);
+
+               if (cnt >= q->max_num_bufs)
+                       goto realloc_failed;