IB/mlx5: Fix outstanding_pi index for GSI qps

commit b5671af upstream.

Commit b0ffeb5 ("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: b0ffeb5 ("IB/mlx5: Fix iteration overrun in GSI qps")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Prabhath Sajeepa <[email protected]>
Acked-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: pspure78

drivers/infiniband/hw/mlx5/gsi.c

@@ -507,8 +507,7 @@ int mlx5_ib_gsi_post_send(struct ib_qp *qp, 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);