在 2021/7/30 下午8:16, Jakub Kicinski 写道:
On Tue, 1 Jun 2021 07:06:43 -0400 Michael S. Tsirkin wrote:
On Tue, Jun 01, 2021 at 02:39:58PM +0800, Xuan Zhuo wrote:
#1 Fixed a serious error.
#2 Fixed a logical error, but this error did not cause any serious consequences.
The logic of this piece is really messy. Fortunately, my refactored patch can be
completed with a small amount of testing.
Looks good, thanks!
Also needed for stable I think.
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Just a heads up folks, looks like we ended up merging both this and the
net-next version of the patch set:
8fb7da9e9907 virtio_net: get build_skb() buf by data ptr
5c37711d9f27 virtio-net: fix for unable to handle page fault for address
and
7bf64460e3b2 virtio-net: get build_skb() buf by data ptr
6c66c147b9a4 virtio-net: fix for unable to handle page fault for address
Are you okay with the code as is or should we commit something like:
I think we need commit the following codes since it's more easier to be
understood.
Thanks
---
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))
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