Commit 35759383 authored by Florian Westphal's avatar Florian Westphal Committed by David S. Miller

mptcp: sendmsg: reset iter on error

Once we've copied data from the iterator we need to revert in case we
end up not sending any data.

This bug doesn't trigger with normal 'poll' based tests, because
we only feed a small chunk of data to kernel after poll indicated
POLLOUT.  With blocking IO and large writes this triggers. Receiver
ends up with less data than it should get.

Fixes: 72511aab ("mptcp: avoid blocking in tcp_sendpages")
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Reviewed-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 06888543
......@@ -725,8 +725,10 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
if (!psize)
return -EINVAL;
if (!sk_wmem_schedule(sk, psize + dfrag->overhead))
if (!sk_wmem_schedule(sk, psize + dfrag->overhead)) {
iov_iter_revert(&msg->msg_iter, psize);
return -ENOMEM;
}
} else {
offset = dfrag->offset;
psize = min_t(size_t, dfrag->data_len, avail_size);
......@@ -737,8 +739,10 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
*/
ret = do_tcp_sendpages(ssk, page, offset, psize,
msg->msg_flags | MSG_SENDPAGE_NOTLAST | MSG_DONTWAIT);
if (ret <= 0)
if (ret <= 0) {
iov_iter_revert(&msg->msg_iter, psize);
return ret;
}
frag_truesize += ret;
if (!retransmission) {
......
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