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From: Wen Gu <guwen@linux.alibaba.com>
To: wintera@linux.ibm.com,
	mjrosato@linux.ibm.com,
	wenjia@linux.ibm.com,
	jaka@linux.ibm.com,
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Cc: alibuda@linux.alibaba.com,
	tonylu@linux.alibaba.com,
	guwen@linux.alibaba.com,
	linux-s390@vger.kernel.org,
	netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH net] net/smc: fix incorrect SMC-D link group matching logic
Date: Thu, 25 Jan 2024 20:39:16 +0800
Message-Id: <20240125123916.77928-1-guwen@linux.alibaba.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

The logic to determine if SMC-D link group matches is incorrect. The
correct logic should be that it only returns true when the GID is the
same, and the SMC-D device is the same and the extended GID is the same
(in the case of virtual ISM).

It can be fixed by adding brackets around the conditional (or ternary)
operator expression. But for better readability and maintainability, it
has been changed to an if-else statement.

Reported-by: Matthew Rosato <mjrosato@linux.ibm.com>
Closes: https://lore.kernel.org/r/13579588-eb9d-4626-a063-c0b77ed80f11@linux.ibm.com
Fixes: b40584d14570 ("net/smc: compatible with 128-bits extended GID of virtual ISM device")
Link: https://lore.kernel.org/r/13579588-eb9d-4626-a063-c0b77ed80f11@linux.ibm.com
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
---
 net/smc/smc_core.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 95cc95458e2d..e4c858411207 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -1877,9 +1877,15 @@ static bool smcd_lgr_match(struct smc_link_group *lgr,
 			   struct smcd_dev *smcismdev,
 			   struct smcd_gid *peer_gid)
 {
-	return lgr->peer_gid.gid == peer_gid->gid && lgr->smcd == smcismdev &&
-		smc_ism_is_virtual(smcismdev) ?
-		(lgr->peer_gid.gid_ext == peer_gid->gid_ext) : 1;
+	if (lgr->peer_gid.gid != peer_gid->gid ||
+	    lgr->smcd != smcismdev)
+		return false;
+
+	if (smc_ism_is_virtual(smcismdev) &&
+	    lgr->peer_gid.gid_ext != peer_gid->gid_ext)
+		return false;
+
+	return true;
 }
 
 /* create a new SMC connection (and a new link group if necessary) */
-- 
2.32.0.3.g01195cf9f