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From: Stanislav Fomichev <stfomichev@gmail.com>
To: netdev@vger.kernel.org
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com, horms@kernel.org, willemb@google.com,
	sagi@grimberg.me, stfomichev@gmail.com, asml.silence@gmail.com,
	almasrymina@google.com, kaiyuanz@google.com,
	linux-kernel@vger.kernel.org
Subject: [PATCH net-next] net: devmem: remove min_t(iter_iov_len) in sendmsg
Date: Fri, 16 May 2025 17:04:31 -0700	[thread overview]
Message-ID: <20250517000431.558180-1-stfomichev@gmail.com> (raw)

iter_iov_len looks broken for UBUF. When iov_iter_advance is called
for UBUF, it increments iov_offset and also decrements the count.
This makes the iterator only go over half of the range (unless I'm
missing something). Remove iter_iov_len clamping. net_devmem_get_niov_at
already does PAGE_SIZE alignment and min_t(length) makes sure that
the last chunk (potentially smaller than PAGE_SIZE) is accounted
correctly.

Fixes: bd61848900bf ("net: devmem: Implement TX path")
Signed-off-by: Stanislav Fomichev <stfomichev@gmail.com>
---
 net/core/datagram.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/core/datagram.c b/net/core/datagram.c
index e04908276a32..48fcfc1dcf47 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -712,7 +712,6 @@ zerocopy_fill_skb_from_devmem(struct sk_buff *skb, struct iov_iter *from,
 			return -EFAULT;
 
 		size = min_t(size_t, size, length);
-		size = min_t(size_t, size, iter_iov_len(from));
 
 		get_netmem(net_iov_to_netmem(niov));
 		skb_add_rx_frag_netmem(skb, i, net_iov_to_netmem(niov), off,
-- 
2.49.0


             reply	other threads:[~2025-05-17  0:04 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-17  0:04 Stanislav Fomichev [this message]
2025-05-17  0:09 ` [PATCH net-next] net: devmem: remove min_t(iter_iov_len) in sendmsg Al Viro
2025-05-17  1:24   ` Stanislav Fomichev
2025-05-17  2:06     ` Al Viro
2025-05-17  2:17       ` Stanislav Fomichev
2025-05-17  3:39         ` Al Viro
2025-05-17  3:53           ` Stanislav Fomichev
2025-05-17  4:05             ` Al Viro
2025-05-17  4:29               ` Stanislav Fomichev
2025-05-17  4:53                 ` Mina Almasry
2025-05-20 15:10                 ` Pavel Begunkov

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