RDMA/irdma: Report the correct max cqes from query device

[ Upstream commit 12faad5 ]

Report the correct max cqes available to an application taking
into account a reserved entry to detect overflow.

Fixes: b48c24c ("RDMA/irdma: Implement device supported verb APIs")
Signed-off-by: Sindhu-Devale <sindhu.devale@intel.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Link: https://lore.kernel.org/r/20220906223244.1119-2-shiraz.saleem@intel.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/infiniband/hw/irdma/verbs.c

@@ -36,7 +36,7 @@ static int irdma_query_device(struct ib_device *ibdev,
 	props->max_send_sge = hw_attrs->uk_attrs.max_hw_wq_frags;
 	props->max_recv_sge = hw_attrs->uk_attrs.max_hw_wq_frags;
 	props->max_cq = rf->max_cq - rf->used_cqs;
-	props->max_cqe = rf->max_cqe;
+	props->max_cqe = rf->max_cqe - 1;
 	props->max_mr = rf->max_mr - rf->used_mrs;
 	props->max_mw = props->max_mr;
 	props->max_pd = rf->max_pd - rf->used_pds;