linux-kernel - [PATCH v3 7/9] videobuf2/videobuf2-dma-sg.c: Convert to use vm_map

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Date:   Wed, 13 Feb 2019 19:36:36 +0530
From:   Souptick Joarder <jrdr.linux@...il.com>
To:     akpm@...ux-foundation.org, willy@...radead.org, mhocko@...e.com,
        pawel@...iak.com, m.szyprowski@...sung.com,
        kyungmin.park@...sung.com, mchehab@...nel.org,
        linux@...linux.org.uk, robin.murphy@....com
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org
Subject: [PATCH v3 7/9] videobuf2/videobuf2-dma-sg.c: Convert to use
 vm_map_pages()

Convert to use vm_map_pages() 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@...il.com>
Suggested-by: Marek Szyprowski <m.szyprowski@...sung.com>
Reviewed-by: Marek Szyprowski <m.szyprowski@...sung.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..d6b8eca 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_map_pages(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