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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Avihai Horon <avihaih@nvidia.com>,
        Mark Zhang <markzhang@nvidia.com>,
        Leon Romanovsky <leonro@nvidia.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 411/846] RDMA/cma: Let cma_resolve_ib_dev() continue search even after empty entry
Date:   Mon, 24 Jan 2022 19:38:48 +0100
Message-Id: <20220124184115.154536797@linuxfoundation.org>
In-Reply-To: <20220124184100.867127425@linuxfoundation.org>
References: <20220124184100.867127425@linuxfoundation.org>
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From: Avihai Horon <avihaih@nvidia.com>

[ Upstream commit 20679094a0161c94faf77e373fa3f7428a8e14bd ]

Currently, when cma_resolve_ib_dev() searches for a matching GID it will
stop searching after encountering the first empty GID table entry. This
behavior is wrong since neither IB nor RoCE spec enforce tightly packed
GID tables.

For example, when the matching valid GID entry exists at index N, and if a
GID entry is empty at index N-1, cma_resolve_ib_dev() will fail to find
the matching valid entry.

Fix it by making cma_resolve_ib_dev() continue searching even after
encountering missing entries.

Fixes: f17df3b0dede ("RDMA/cma: Add support for AF_IB to rdma_resolve_addr()")
Link: https://lore.kernel.org/r/b7346307e3bb396c43d67d924348c6c496493991.1639055490.git.leonro@nvidia.com
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Mark Zhang <markzhang@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/core/cma.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 704ce595542c5..88093bbe3da69 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -766,6 +766,7 @@ static int cma_resolve_ib_dev(struct rdma_id_private *id_priv)
 	unsigned int p;
 	u16 pkey, index;
 	enum ib_port_state port_state;
+	int ret;
 	int i;
 
 	cma_dev = NULL;
@@ -784,9 +785,14 @@ static int cma_resolve_ib_dev(struct rdma_id_private *id_priv)
 
 			if (ib_get_cached_port_state(cur_dev->device, p, &port_state))
 				continue;
-			for (i = 0; !rdma_query_gid(cur_dev->device,
-						    p, i, &gid);
-			     i++) {
+
+			for (i = 0; i < cur_dev->device->port_data[p].immutable.gid_tbl_len;
+			     ++i) {
+				ret = rdma_query_gid(cur_dev->device, p, i,
+						     &gid);
+				if (ret)
+					continue;
+
 				if (!memcmp(&gid, dgid, sizeof(gid))) {
 					cma_dev = cur_dev;
 					sgid = gid;
-- 
2.34.1