[PATCH 4.9 018/107] qed: Fix possible race for the link state value.

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sudarsana Reddy Kalluru <sudarsana.kalluru@xxxxxxxxxx>

[ Upstream commit 58874c7b246109d8efb2b0099d1aa296d6bfc3fa ]

There's a possible race where driver can read link status in mid-transition
and see that virtual-link is up yet speed is 0. Since in this
mid-transition we're guaranteed to see a mailbox from MFW soon, we can
afford to treat this as link down.

Fixes: cc875c2e ("qed: Add link support")
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@xxxxxxxxxx>
Signed-off-by: Ariel Elior <ariel.elior@xxxxxxxxxx>
Signed-off-by: Michal Kalderon <Michal.Kalderon@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/qlogic/qed/qed_mcp.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
@@ -613,6 +613,7 @@ static void qed_mcp_handle_link_change(s
 		break;
 	default:
 		p_link->speed = 0;
+		p_link->link_up = 0;
 	}
 
 	if (p_link->link_up && p_link->speed)