From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Wen Gu <guwen@linux.alibaba.com>,
        Tony Lu <tonylu@linux.alibaba.com>,
        Karsten Graul <kgraul@linux.ibm.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 121/279] net/smc: Make sure the link_id is unique
Date:   Wed, 24 Nov 2021 12:56:48 +0100
Message-Id: <20211124115722.987330723@linuxfoundation.org>
In-Reply-To: <20211124115718.776172708@linuxfoundation.org>
References: <20211124115718.776172708@linuxfoundation.org>
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From: Wen Gu <guwen@linux.alibaba.com>

[ Upstream commit cf4f5530bb55ef7d5a91036b26676643b80b1616 ]

The link_id is supposed to be unique, but smcr_next_link_id() doesn't
skip the used link_id as expected. So the patch fixes this.

Fixes: 026c381fb477 ("net/smc: introduce link_idx for link group array")
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/smc/smc_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index d2206743dc714..d672c0f0e247f 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -665,13 +665,14 @@ static u8 smcr_next_link_id(struct smc_link_group *lgr)
 	int i;
 
 	while (1) {
+again:
 		link_id = ++lgr->next_link_id;
 		if (!link_id)	/* skip zero as link_id */
 			link_id = ++lgr->next_link_id;
 		for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
 			if (smc_link_usable(&lgr->lnk[i]) &&
 			    lgr->lnk[i].link_id == link_id)
-				continue;
+				goto again;
 		}
 		break;
 	}
-- 
2.33.0