[PATCH 4.14 13/67] qed: Fix reading wrong value in loop condition

Greg Kroah-Hartman
2018-12-11T15:51:21Z

[ Upstream commit ed4eac20dcffdad47709422e0cb925981b056668 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/qlogic/qed/qed_int.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_int.c b/drivers/net/ethernet/qlogic/qed/qed_int.c
index 719cdbfe1695..7746417130bd 100644
--- 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_hwfn *p_hwfn)
*/
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);
--
2.19.1