[PATCH 6.12.y] RDMA/mana: Remove user triggerable WARN_ON() in mana_ib_create_qp_rss()

[Sasha Levin <sashal@kernel.org>]

From: Jason Gunthorpe <jgg@nvidia.com>

[ Upstream commit 159f2efabc89d3f931d38f2d35876535d4abf0a3 ]

Sashiko points out that the user can specify WQs sharing the same CQ as a
part of the uAPI and this will trigger the WARN_ON() then go on to corrupt
the kernel.

Just reject it outright and fail the QP creation.

Cc: stable@vger.kernel.org
Fixes: c15d7802a424 ("RDMA/mana_ib: Add CQ interrupt support for RAW QP")
Link: https://sashiko.dev/#/patchset/0-v2-1c49eeb88c48%2B91-rdma_udata_rep_jgg%40nvidia.com?part=1
Link: https://patch.msgid.link/r/5-v1-41f3135e5565+9d2-rdma_ai_fixes1_jgg@nvidia.com
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
[ adjusted context ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/hw/mana/cq.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mana/cq.c b/drivers/infiniband/hw/mana/cq.c
index f04a679d28714..54cf3868b2977 100644
--- a/drivers/infiniband/hw/mana/cq.c
+++ b/drivers/infiniband/hw/mana/cq.c
@@ -120,8 +120,9 @@ int mana_ib_install_cq_cb(struct mana_ib_dev *mdev, struct mana_ib_cq *cq)
 
 	if (cq->queue.id >= gc->max_num_cqs)
 		return -EINVAL;
-	/* Create CQ table entry */
-	WARN_ON(gc->cq_table[cq->queue.id]);
+	/* Create CQ table entry, sharing a CQ between WQs is not supported */
+	if (gc->cq_table[cq->queue.id])
+		return -EINVAL;
 	gdma_cq = kzalloc(sizeof(*gdma_cq), GFP_KERNEL);
 	if (!gdma_cq)
 		return -ENOMEM;
-- 
2.53.0