qed*: Fix link indication race

Driver changes the link properties via communication with
the management firmware, and re-reads the resulting link status
when it receives an indication that the link has changed.
However, there are certain scenarios where such indications
might be missing, and so driver also re-reads the current link
results without attention in several places. Specifically, it
does so during load and when resetting the link.

This creates a race where driver might reflect incorrect
link status - e.g., when explicit reading of the link status is
switched by attention with the changed configuration.

Correct this flow by a lock syncronizing the handling of the
link indications [both explicit requests and attention].

Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 3 deletions

diff --git a/drivers/net/ethernet/qlogic/qed/qed_main.c b/drivers/net/ethernet/qlogic/qed/qed_main.c
index 4440ae7ec85b..eef30a598b40 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_main.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_main.c
@@ -1146,12 +1146,18 @@ static int qed_set_link(struct qed_dev *cdev, struct qed_link_params *params)
 	if (!cdev)
 		return -ENODEV;
 
-	if (IS_VF(cdev))
-		return 0;
-
 	/* The link should be set only once per PF */
 	hwfn = &cdev->hwfns[0];
 
+	/* When VF wants to set link, force it to read the bulletin instead.
+	 * This mimics the PF behavior, where a noitification [both immediate
+	 * and possible later] would be generated when changing properties.
+	 */
+	if (IS_VF(cdev)) {
+		qed_schedule_iov(hwfn, QED_IOV_WQ_VF_FORCE_LINK_QUERY_FLAG);
+		return 0;
+	}
+
 	ptt = qed_ptt_acquire(hwfn);
 	if (!ptt)
 		return -EBUSY;