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From: Bui Quang Minh <minhquangbui99@gmail.com>
To: netdev@vger.kernel.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	"Jason Wang" <jasowang@redhat.com>,
	"Xuan Zhuo" <xuanzhuo@linux.alibaba.com>,
	"Eugenio Pérez" <eperezma@redhat.com>,
	"Andrew Lunn" <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Paolo Abeni" <pabeni@redhat.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Jesper Dangaard Brouer" <hawk@kernel.org>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"Stanislav Fomichev" <sdf@fomichev.me>,
	virtualization@lists.linux.dev, linux-kernel@vger.kernel.org,
	bpf@vger.kernel.org, "Bui Quang Minh" <minhquangbui99@gmail.com>
Subject: [PATCH net 2/4] virtio-net: remove redundant truesize check with PAGE_SIZE
Date: Wed, 25 Jun 2025 23:08:47 +0700	[thread overview]
Message-ID: <20250625160849.61344-3-minhquangbui99@gmail.com> (raw)
In-Reply-To: <20250625160849.61344-1-minhquangbui99@gmail.com>

The truesize is guaranteed not to exceed PAGE_SIZE in
get_mergeable_buf_len(). It is saved in mergeable context, which is not
changeable by the host side, so the check in receive path is quite
redundant.

Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
---
 drivers/net/virtio_net.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 2a130a3e50ac..6f9fedad4a5e 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2144,9 +2144,9 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
 {
 	struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
 	unsigned int headroom, tailroom, room;
-	unsigned int truesize, cur_frag_size;
 	struct skb_shared_info *shinfo;
 	unsigned int xdp_frags_truesz = 0;
+	unsigned int truesize;
 	struct page *page;
 	skb_frag_t *frag;
 	int offset;
@@ -2194,9 +2194,8 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
 		tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
 		room = SKB_DATA_ALIGN(headroom + tailroom);
 
-		cur_frag_size = truesize;
-		xdp_frags_truesz += cur_frag_size;
-		if (unlikely(len > truesize - room || cur_frag_size > PAGE_SIZE)) {
+		xdp_frags_truesz += truesize;
+		if (unlikely(len > truesize - room)) {
 			put_page(page);
 			pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
 				 dev->name, len, (unsigned long)(truesize - room));
-- 
2.43.0


  parent reply	other threads:[~2025-06-25 16:10 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-25 16:08 [PATCH net 0/4] virtio-net: fixes for mergeable XDP receive path Bui Quang Minh
2025-06-25 16:08 ` [PATCH net 1/4] virtio-net: ensure the received length does not exceed allocated size Bui Quang Minh
2025-06-26  2:34   ` Jason Wang
2025-06-26 15:34     ` Bui Quang Minh
2025-06-27  2:42       ` Jason Wang
2025-06-25 16:08 ` Bui Quang Minh [this message]
2025-06-26  2:37   ` [PATCH net 2/4] virtio-net: remove redundant truesize check with PAGE_SIZE Jason Wang
2025-06-25 16:08 ` [PATCH net 3/4] virtio-net: create a helper to check received mergeable buffer's length Bui Quang Minh
2025-06-26  2:38   ` Jason Wang
2025-06-26 15:37     ` Bui Quang Minh
2025-06-27  2:43       ` Jason Wang
2025-06-25 16:08 ` [PATCH net 4/4] virtio-net: allow more allocated space for mergeable XDP Bui Quang Minh
2025-06-26  2:51   ` Jason Wang

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