[PATCH net-next] virtio-net: realign page_to_skb() after merges

Subsystems: networking drivers, the rest, virtio net driver

STALE1853d REVIEWED: 9 (9M)

1 review trailer (1 from subsystem maintainers).

4 messages, 4 authors, 2021-08-03 · open the first message on its own page

[PATCH net-next] virtio-net: realign page_to_skb() after merges

From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-08-02 17:57:41

We ended up merging two versions of the same patch set:

commit 8fb7da9e9907 ("virtio_net: get build_skb() buf by data ptr")
commit 5c37711d9f27 ("virtio-net: fix for unable to handle page fault for address")

into net, and

commit 7bf64460e3b2 ("virtio-net: get build_skb() buf by data ptr")
commit 6c66c147b9a4 ("virtio-net: fix for unable to handle page fault for address")

into net-next. Redo the merge from commit 126285651b7f ("Merge
ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net"), so that
the most recent code remains.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/virtio_net.c | 27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 56c3f8519093..74482a52f076 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -380,7 +380,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 				   struct page *page, unsigned int offset,
 				   unsigned int len, unsigned int truesize,
 				   bool hdr_valid, unsigned int metasize,
-				   bool whole_page)
+				   unsigned int headroom)
 {
 	struct sk_buff *skb;
 	struct virtio_net_hdr_mrg_rxbuf *hdr;

@@ -398,28 +398,16 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 	else
 		hdr_padded_len = sizeof(struct padded_vnet_hdr);
 
-	/* If whole_page, there is an offset between the beginning of the
+	/* If headroom is not 0, there is an offset between the beginning of the
 	 * data and the allocated space, otherwise the data and the allocated
 	 * space are aligned.
 	 *
 	 * Buffers with headroom use PAGE_SIZE as alloc size, see
 	 * add_recvbuf_mergeable() + get_mergeable_buf_len()
 	 */
-	if (whole_page) {
-		/* Buffers with whole_page use PAGE_SIZE as alloc size,
-		 * see add_recvbuf_mergeable() + get_mergeable_buf_len()
-		 */
-		truesize = PAGE_SIZE;
-
-		/* page maybe head page, so we should get the buf by p, not the
-		 * page
-		 */
-		tailroom = truesize - len - offset_in_page(p);
-		buf = (char *)((unsigned long)p & PAGE_MASK);
-	} else {
-		tailroom = truesize - len;
-		buf = p;
-	}
+	truesize = headroom ? PAGE_SIZE : truesize;
+	tailroom = truesize - len - headroom;
+	buf = p - headroom;
 
 	len -= hdr_len;
 	offset += hdr_padded_len;

@@ -978,7 +966,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 				put_page(page);
 				head_skb = page_to_skb(vi, rq, xdp_page, offset,
 						       len, PAGE_SIZE, false,
-						       metasize, true);
+						       metasize,
+						       VIRTIO_XDP_HEADROOM);
 				return head_skb;
 			}
 			break;

@@ -1029,7 +1018,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 	rcu_read_unlock();
 
 	head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog,
-			       metasize, !!headroom);
+			       metasize, headroom);
 	curr_skb = head_skb;
 
 	if (unlikely(!curr_skb))

-- 
2.31.1

Re: [PATCH net-next] virtio-net: realign page_to_skb() after merges

From: Jason Wang <hidden>
Date: 2021-08-03 02:51:31

在 2021/8/3 上午1:57, Jakub Kicinski 写道:

We ended up merging two versions of the same patch set:

commit 8fb7da9e9907 ("virtio_net: get build_skb() buf by data ptr")
commit 5c37711d9f27 ("virtio-net: fix for unable to handle page fault for address")

into net, and

commit 7bf64460e3b2 ("virtio-net: get build_skb() buf by data ptr")
commit 6c66c147b9a4 ("virtio-net: fix for unable to handle page fault for address")

into net-next. Redo the merge from commit 126285651b7f ("Merge
ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net"), so that
the most recent code remains.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>


Acked-by: Jason Wang <redacted>

quoted hunk

---
  drivers/net/virtio_net.c | 27 ++++++++-------------------
  1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 56c3f8519093..74482a52f076 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -380,7 +380,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
  				   struct page *page, unsigned int offset,
  				   unsigned int len, unsigned int truesize,
  				   bool hdr_valid, unsigned int metasize,
-				   bool whole_page)
+				   unsigned int headroom)
  {
  	struct sk_buff *skb;
  	struct virtio_net_hdr_mrg_rxbuf *hdr;

@@ -398,28 +398,16 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
  	else
  		hdr_padded_len = sizeof(struct padded_vnet_hdr);
  
-	/* If whole_page, there is an offset between the beginning of the
+	/* If headroom is not 0, there is an offset between the beginning of the
  	 * data and the allocated space, otherwise the data and the allocated
  	 * space are aligned.
  	 *
  	 * Buffers with headroom use PAGE_SIZE as alloc size, see
  	 * add_recvbuf_mergeable() + get_mergeable_buf_len()
  	 */
-	if (whole_page) {
-		/* Buffers with whole_page use PAGE_SIZE as alloc size,
-		 * see add_recvbuf_mergeable() + get_mergeable_buf_len()
-		 */
-		truesize = PAGE_SIZE;
-
-		/* page maybe head page, so we should get the buf by p, not the
-		 * page
-		 */
-		tailroom = truesize - len - offset_in_page(p);
-		buf = (char *)((unsigned long)p & PAGE_MASK);
-	} else {
-		tailroom = truesize - len;
-		buf = p;
-	}
+	truesize = headroom ? PAGE_SIZE : truesize;
+	tailroom = truesize - len - headroom;
+	buf = p - headroom;
  
  	len -= hdr_len;
  	offset += hdr_padded_len;

@@ -978,7 +966,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
  				put_page(page);
  				head_skb = page_to_skb(vi, rq, xdp_page, offset,
  						       len, PAGE_SIZE, false,
-						       metasize, true);
+						       metasize,
+						       VIRTIO_XDP_HEADROOM);
  				return head_skb;
  			}
  			break;

@@ -1029,7 +1018,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
  	rcu_read_unlock();
  
  	head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog,
-			       metasize, !!headroom);
+			       metasize, headroom);
  	curr_skb = head_skb;
  
  	if (unlikely(!curr_skb))

Re: [PATCH net-next] virtio-net: realign page_to_skb() after merges

From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2021-08-03 06:22:28

On Mon, Aug 02, 2021 at 10:57:29AM -0700, Jakub Kicinski wrote:

We ended up merging two versions of the same patch set:

commit 8fb7da9e9907 ("virtio_net: get build_skb() buf by data ptr")
commit 5c37711d9f27 ("virtio-net: fix for unable to handle page fault for address")

into net, and

commit 7bf64460e3b2 ("virtio-net: get build_skb() buf by data ptr")
commit 6c66c147b9a4 ("virtio-net: fix for unable to handle page fault for address")

into net-next. Redo the merge from commit 126285651b7f ("Merge
ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net"), so that
the most recent code remains.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

And maybe add

Fixes: 126285651b7f ("Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net")

so automated tools have an easier time finding this fixup.

quoted hunk

---
 drivers/net/virtio_net.c | 27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 56c3f8519093..74482a52f076 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -380,7 +380,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 				   struct page *page, unsigned int offset,
 				   unsigned int len, unsigned int truesize,
 				   bool hdr_valid, unsigned int metasize,
-				   bool whole_page)
+				   unsigned int headroom)
 {
 	struct sk_buff *skb;
 	struct virtio_net_hdr_mrg_rxbuf *hdr;

@@ -398,28 +398,16 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 	else
 		hdr_padded_len = sizeof(struct padded_vnet_hdr);
 
-	/* If whole_page, there is an offset between the beginning of the
+	/* If headroom is not 0, there is an offset between the beginning of the
 	 * data and the allocated space, otherwise the data and the allocated
 	 * space are aligned.
 	 *
 	 * Buffers with headroom use PAGE_SIZE as alloc size, see
 	 * add_recvbuf_mergeable() + get_mergeable_buf_len()
 	 */
-	if (whole_page) {
-		/* Buffers with whole_page use PAGE_SIZE as alloc size,
-		 * see add_recvbuf_mergeable() + get_mergeable_buf_len()
-		 */
-		truesize = PAGE_SIZE;
-
-		/* page maybe head page, so we should get the buf by p, not the
-		 * page
-		 */
-		tailroom = truesize - len - offset_in_page(p);
-		buf = (char *)((unsigned long)p & PAGE_MASK);
-	} else {
-		tailroom = truesize - len;
-		buf = p;
-	}
+	truesize = headroom ? PAGE_SIZE : truesize;
+	tailroom = truesize - len - headroom;
+	buf = p - headroom;
 
 	len -= hdr_len;
 	offset += hdr_padded_len;

@@ -978,7 +966,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 				put_page(page);
 				head_skb = page_to_skb(vi, rq, xdp_page, offset,
 						       len, PAGE_SIZE, false,
-						       metasize, true);
+						       metasize,
+						       VIRTIO_XDP_HEADROOM);
 				return head_skb;
 			}
 			break;

@@ -1029,7 +1018,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 	rcu_read_unlock();
 
 	head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog,
-			       metasize, !!headroom);
+			       metasize, headroom);
 	curr_skb = head_skb;
 
 	if (unlikely(!curr_skb))

-- 
2.31.1

Re: [PATCH net-next] virtio-net: realign page_to_skb() after merges

From: patchwork-bot+netdevbpf@kernel.org
Date: 2021-08-03 11:50:08

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Mon,  2 Aug 2021 10:57:29 -0700 you wrote:

We ended up merging two versions of the same patch set:

commit 8fb7da9e9907 ("virtio_net: get build_skb() buf by data ptr")
commit 5c37711d9f27 ("virtio-net: fix for unable to handle page fault for address")

into net, and

[...]

Here is the summary with links:
  - [net-next] virtio-net: realign page_to_skb() after merges
    https://git.kernel.org/netdev/net-next/c/c32325b8fdf2

You are awesome, thank you!
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