netdev - [PATCH net 3/3] smc: fix sendpage() call

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Message-Id: <20180503155739.55616-4-ubraun@linux.ibm.com>
Date:   Thu,  3 May 2018 17:57:39 +0200
From:   Ursula Braun <ubraun@...ux.ibm.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        schwidefsky@...ibm.com, heiko.carstens@...ibm.com,
        raspl@...ux.ibm.com, ubraun@...ux.ibm.com
Subject: [PATCH net 3/3] smc: fix sendpage() call

From: Stefan Raspl <stefan.raspl@...ux.ibm.com>

The sendpage() call grabs the sock lock before calling the default
implementation - which tries to grab it once again.

Signed-off-by: Stefan Raspl <raspl@...ux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@...ux.ibm.com><
---
 net/smc/af_smc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index d03b8d29ffc0..544bab42f925 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1315,8 +1315,11 @@ static ssize_t smc_sendpage(struct socket *sock, struct page *page,
 
 	smc = smc_sk(sk);
 	lock_sock(sk);
-	if (sk->sk_state != SMC_ACTIVE)
+	if (sk->sk_state != SMC_ACTIVE) {
+		release_sock(sk);
 		goto out;
+	}
+	release_sock(sk);
 	if (smc->use_fallback)
 		rc = kernel_sendpage(smc->clcsock, page, offset,
 				     size, flags);
@@ -1324,7 +1327,6 @@ static ssize_t smc_sendpage(struct socket *sock, struct page *page,
 		rc = sock_no_sendpage(sock, page, offset, size, flags);
 
 out:
-	release_sock(sk);
 	return rc;
 }
 
-- 
2.13.5