IB/mlx5: Fix outstanding_pi index for GSI qps

commit b5671afe5e39ed71e94eae788bacdcceec69db09 upstream.

Commit b0ffeb537f3a ("IB/mlx5: Fix iteration overrun in GSI qps") changed
the way outstanding WRs are tracked for the GSI QP. But the fix did not
cover the case when a call to ib_post_send() fails and updates index to
track outstanding.

Since the prior commmit outstanding_pi should not be bounded otherwise the
loop generate_completions() will fail.

Fixes: b0ffeb537f3a ("IB/mlx5: Fix iteration overrun in GSI qps")
Link: https://lore.kernel.org/r/1576195889-23527-1-git-send-email-psajeepa@purestorage.com
Signed-off-by: Prabhath Sajeepa <psajeepa@purestorage.com>
Acked-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/infiniband/hw/mlx5/gsi.c b/drivers/infiniband/hw/mlx5/gsi.c
index 4950df3..5c73c0a 100644 (file)
--- a/drivers/infiniband/hw/mlx5/gsi.c
+++ b/drivers/infiniband/hw/mlx5/gsi.c
@@ -507,8 +507,7 @@ int mlx5_ib_gsi_post_send(struct ib_qp *qp, const struct ib_send_wr *wr,
                ret = ib_post_send(tx_qp, &cur_wr.wr, bad_wr);
                if (ret) {
                        /* Undo the effect of adding the outstanding wr */
-                       gsi->outstanding_pi = (gsi->outstanding_pi - 1) %
-                                             gsi->cap.max_send_wr;
+                       gsi->outstanding_pi--;
                        goto err;
                }
                spin_unlock_irqrestore(&gsi->lock, flags);