From: Denis Bolotin <denis.bolotin@cavium.com>
Date: Mon, 12 Nov 2018 12:50:23 +0200
Subject: qed: Fix reading wrong value in loop condition
Patch-mainline: v4.20-rc4
Git-commit: ed4eac20dcffdad47709422e0cb925981b056668
References: bsc#1104393 FATE#325891 bsc#1104389 FATE#325890

The value of "sb_index" is written by the hardware. Reading its value and
writing it to "index" must finish before checking the loop condition.

Signed-off-by: Denis Bolotin <denis.bolotin@cavium.com>
Signed-off-by: Michal Kalderon <michal.kalderon@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/qlogic/qed/qed_int.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/ethernet/qlogic/qed/qed_int.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_int.c
@@ -992,6 +992,8 @@ static int qed_int_attentions(struct qed
 	 */
 	do {
 		index = p_sb_attn->sb_index;
+		/* finish reading index before the loop condition */
+		dma_rmb();
 		attn_bits = le32_to_cpu(p_sb_attn->atten_bits);
 		attn_acks = le32_to_cpu(p_sb_attn->atten_ack);
 	} while (index != p_sb_attn->sb_index);