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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     David Howells <dhowells@redhat.com>,
        Sasha Levin <sashal@kernel.org>, linux-afs@lists.infradead.org,
        netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.5 15/35] rxrpc: Fix sendmsg(MSG_WAITALL) handling
Date:   Mon,  6 Apr 2020 20:00:37 -0400
Message-Id: <20200407000058.16423-15-sashal@kernel.org>
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From: David Howells <dhowells@redhat.com>

[ Upstream commit 498b577660f08cef5d9e78e0ed6dcd4c0939e98c ]

Fix the handling of sendmsg() with MSG_WAITALL for userspace to round the
timeout for when a signal occurs up to at least two jiffies as a 1 jiffy
timeout may end up being effectively 0 if jiffies wraps at the wrong time.

Fixes: bc5e3a546d55 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/rxrpc/sendmsg.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 1eccfb92c9e15..0fcf157aa09f8 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -71,8 +71,8 @@ static int rxrpc_wait_for_tx_window_waitall(struct rxrpc_sock *rx,
 
 	rtt = READ_ONCE(call->peer->rtt);
 	rtt2 = nsecs_to_jiffies64(rtt) * 2;
-	if (rtt2 < 1)
-		rtt2 = 1;
+	if (rtt2 < 2)
+		rtt2 = 2;
 
 	timeout = rtt2;
 	tx_start = READ_ONCE(call->tx_hard_ack);
-- 
2.20.1