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[media] v4l: vb2-dma-contig: remove reference of alloc_ctx from a buffer 

This patch removes a reference to alloc_ctx from an instance of a DMA
contiguous buffer. It helps to avoid a risk of a dangling pointer if the
context is released while the buffer is still valid. Moreover it removes one
dereference step while accessing a device structure.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Tomasz Stanislawski 2012-06-14 10:37:40 -03:00 committed by Mauro Carvalho Chehab
parent f7f129ce2e
commit 72f86bffbc
1 changed files with 6 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/media/v4l2-core/videobuf2-dma-contig.c
View File

@ -23,7 +23,7 @@ struct vb2_dc_conf {
};
struct vb2_dc_buf {
struct vb2_dc_conf *conf;
struct device *dev;
void *vaddr;
dma_addr_t dma_addr;
unsigned long size;
@ -37,22 +37,21 @@ static void vb2_dc_put(void *buf_priv);
static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
{
struct vb2_dc_conf *conf = alloc_ctx;
struct device *dev = conf->dev;
struct vb2_dc_buf *buf;
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)
return ERR_PTR(-ENOMEM);
buf->vaddr = dma_alloc_coherent(conf->dev, size, &buf->dma_addr,
GFP_KERNEL);
buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
if (!buf->vaddr) {
dev_err(conf->dev, "dma_alloc_coherent of size %ld failed\n",
size);
dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
kfree(buf);
return ERR_PTR(-ENOMEM);
}
buf->conf = conf;
buf->dev = dev;
buf->size = size;
buf->handler.refcount = &buf->refcount;
@ -69,7 +68,7 @@ static void vb2_dc_put(void *buf_priv)
struct vb2_dc_buf *buf = buf_priv;
if (atomic_dec_and_test(&buf->refcount)) {
dma_free_coherent(buf->conf->dev, buf->size, buf->vaddr,
dma_free_coherent(buf->dev, buf->size, buf->vaddr,
buf->dma_addr);
kfree(buf);
}