[PATCHv2 7/9] videobuf2/videobuf2-dma-sg.c: Convert to use vm_insert_range

[PATCHv2 7/9] videobuf2/videobuf2-dma-sg.c: Convert to use vm_insert_range

[Souptick Joarder]

Convert to use vm_insert_range to map range of kernel memory
to user vma.

vm_pgoff is treated in V4L2 API as a 'cookie' to select a buffer,
not as a in-buffer offset by design and it always want to mmap a
whole buffer from its beginning.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
---
 drivers/media/common/videobuf2/videobuf2-core.c    |  7 +++++++
 .../media/common/videobuf2/videobuf2-dma-contig.c  |  6 ------
 drivers/media/common/videobuf2/videobuf2-dma-sg.c  | 22 ++++++----------------
 3 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 70e8c33..ca4577a 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -2175,6 +2175,13 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
 		goto unlock;
 	}
 
+	/*
+	 * vm_pgoff is treated in V4L2 API as a 'cookie' to select a buffer,
+	 * not as a in-buffer offset. We always want to mmap a whole buffer
+	 * from its beginning.
+	 */
+	vma->vm_pgoff = 0;
+
 	ret = call_memop(vb, mmap, vb->planes[plane].mem_priv, vma);
 
 unlock:
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index aff0ab7..46245c5 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -186,12 +186,6 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 		return -EINVAL;
 	}
 
-	/*
-	 * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
-	 * map whole buffer
-	 */
-	vma->vm_pgoff = 0;
-
 	ret = dma_mmap_attrs(buf->dev, vma, buf->cookie,
 		buf->dma_addr, buf->size, buf->attrs);
 
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
index 015e737..a800200 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -328,28 +328,18 @@ static unsigned int vb2_dma_sg_num_users(void *buf_priv)
 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
 {
 	struct vb2_dma_sg_buf *buf = buf_priv;
-	unsigned long uaddr = vma->vm_start;
-	unsigned long usize = vma->vm_end - vma->vm_start;
-	int i = 0;
+	int err;
 
 	if (!buf) {
 		printk(KERN_ERR "No memory to map\n");
 		return -EINVAL;
 	}
 
-	do {
-		int ret;
-
-		ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
-		if (ret) {
-			printk(KERN_ERR "Remapping memory, error: %d\n", ret);
-			return ret;
-		}
-
-		uaddr += PAGE_SIZE;
-		usize -= PAGE_SIZE;
-	} while (usize > 0);
-
+	err = vm_insert_range(vma, buf->pages, buf->num_pages);
+	if (err) {
+		printk(KERN_ERR "Remapping memory, error: %d\n", err);
+		return err;
+	}
 
 	/*
 	 * Use common vm_area operations to track buffer refcount.
-- 
1.9.1

Re: [PATCHv2 7/9] videobuf2/videobuf2-dma-sg.c: Convert to use vm_insert_range

[Marek Szyprowski]

Hi Souptick,

On 2019-01-31 04:13, Souptick Joarder wrote:
> Convert to use vm_insert_range to map range of kernel memory
> to user vma.
>
> vm_pgoff is treated in V4L2 API as a 'cookie' to select a buffer,
> not as a in-buffer offset by design and it always want to mmap a
> whole buffer from its beginning.
>
> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>

Suggested-by: Marek Szyprowski <m.szyprowski@samsung.com>

Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>

> ---
>  drivers/media/common/videobuf2/videobuf2-core.c    |  7 +++++++
>  .../media/common/videobuf2/videobuf2-dma-contig.c  |  6 ------
>  drivers/media/common/videobuf2/videobuf2-dma-sg.c  | 22 ++++++----------------
>  3 files changed, 13 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index 70e8c33..ca4577a 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -2175,6 +2175,13 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
>  		goto unlock;
>  	}
>  
> +	/*
> +	 * vm_pgoff is treated in V4L2 API as a 'cookie' to select a buffer,
> +	 * not as a in-buffer offset. We always want to mmap a whole buffer
> +	 * from its beginning.
> +	 */
> +	vma->vm_pgoff = 0;
> +
>  	ret = call_memop(vb, mmap, vb->planes[plane].mem_priv, vma);
>  
>  unlock:
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index aff0ab7..46245c5 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -186,12 +186,6 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
>  		return -EINVAL;
>  	}
>  
> -	/*
> -	 * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
> -	 * map whole buffer
> -	 */
> -	vma->vm_pgoff = 0;
> -
>  	ret = dma_mmap_attrs(buf->dev, vma, buf->cookie,
>  		buf->dma_addr, buf->size, buf->attrs);
>  
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> index 015e737..a800200 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
> @@ -328,28 +328,18 @@ static unsigned int vb2_dma_sg_num_users(void *buf_priv)
>  static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
>  {
>  	struct vb2_dma_sg_buf *buf = buf_priv;
> -	unsigned long uaddr = vma->vm_start;
> -	unsigned long usize = vma->vm_end - vma->vm_start;
> -	int i = 0;
> +	int err;
>  
>  	if (!buf) {
>  		printk(KERN_ERR "No memory to map\n");
>  		return -EINVAL;
>  	}
>  
> -	do {
> -		int ret;
> -
> -		ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
> -		if (ret) {
> -			printk(KERN_ERR "Remapping memory, error: %d\n", ret);
> -			return ret;
> -		}
> -
> -		uaddr += PAGE_SIZE;
> -		usize -= PAGE_SIZE;
> -	} while (usize > 0);
> -
> +	err = vm_insert_range(vma, buf->pages, buf->num_pages);
> +	if (err) {
> +		printk(KERN_ERR "Remapping memory, error: %d\n", err);
> +		return err;
> +	}
>  
>  	/*
>  	 * Use common vm_area operations to track buffer refcount.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland