[PATCH 4.20 043/171] qed: Fix VF probe failure while FLR

[Greg Kroah-Hartman]

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

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

[ Upstream commit 327852ec64205bb651be391a069784872098a3b2 ]

VFs may hit VF-PF channel timeout while probing, as in some
cases it was observed that VF FLR and VF "acquire" message
transaction (i.e first message from VF to PF in VF's probe flow)
could occur simultaneously which could lead VF to fail sending
"acquire" message to PF as VF is marked disabled from HW perspective
due to FLR, which will result into channel timeout and VF probe failure.

In such cases, try retrying VF "acquire" message so that in later
attempts it could be successful to pass message to PF after the VF
FLR is completed and can be probed successfully.

Signed-off-by: Manish Chopra <manishc@xxxxxxxxxxx>
Signed-off-by: Ariel Elior <aelior@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/ethernet/qlogic/qed/qed_vf.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_vf.c b/drivers/net/ethernet/qlogic/qed/qed_vf.c
index b6cccf44bf40..5dda547772c1 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_vf.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_vf.c
@@ -261,6 +261,7 @@ static int qed_vf_pf_acquire(struct qed_hwfn *p_hwfn)
 	struct pfvf_acquire_resp_tlv *resp = &p_iov->pf2vf_reply->acquire_resp;
 	struct pf_vf_pfdev_info *pfdev_info = &resp->pfdev_info;
 	struct vf_pf_resc_request *p_resc;
+	u8 retry_cnt = VF_ACQUIRE_THRESH;
 	bool resources_acquired = false;
 	struct vfpf_acquire_tlv *req;
 	int rc = 0, attempts = 0;
@@ -314,6 +315,15 @@ static int qed_vf_pf_acquire(struct qed_hwfn *p_hwfn)
 
 		/* send acquire request */
 		rc = qed_send_msg2pf(p_hwfn, &resp->hdr.status, sizeof(*resp));
+
+		/* Re-try acquire in case of vf-pf hw channel timeout */
+		if (retry_cnt && rc == -EBUSY) {
+			DP_VERBOSE(p_hwfn, QED_MSG_IOV,
+				   "VF retrying to acquire due to VPC timeout\n");
+			retry_cnt--;
+			continue;
+		}
+
 		if (rc)
 			goto exit;
 
-- 
2.19.1