RE: [PATCH] qla3xxx: Ensure request/response queue addr writes to the registers

From: Joe Jin [mailto:joe.jin@oracle.com] 
Sent: Sunday, October 21, 2012 5:41 PM
To: Jitendra Kalsaria; Ron Mercer; Dept-Eng Linux Driver; David Miller; Andrew Morton
Cc: netdev; linux-kernel; Greg Marsden
Subject: [PATCH] qla3xxx: Ensure request/response queue addr writes to the registers

Before use the request and response queue addr, make sure it has wrote
to the registers.

Signed-off-by: Joe Jin <redacted>
Cc: Jitendra Kalsaria <redacted>
Cc: Ron Mercer <redacted>
---
drivers/net/ethernet/qlogic/qla3xxx.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qla3xxx.c b/drivers/net/ethernet/qlogic/qla3xxx.c
index df09b1c..6407d0d 100644
--- a/drivers/net/ethernet/qlogic/qla3xxx.c
+++ b/drivers/net/ethernet/qlogic/qla3xxx.c

@@ -2525,6 +2525,13 @@ static int ql_alloc_net_req_rsp_queues(struct ql3_adapter *qdev)

	qdev->req_q_size =
	    (u32) (NUM_REQ_Q_ENTRIES * sizeof(struct ob_mac_iocb_req));

+	qdev->rsp_q_size = NUM_RSP_Q_ENTRIES * sizeof(struct net_rsp_iocb);
+
+	/* The barrier is required to ensure request and response queue
+	 * addr writes to the registers.
+	 */
+	wmb();
+
	qdev->req_q_virt_addr =
	    pci_alloc_consistent(qdev->pdev,
				 (size_t) qdev->req_q_size,

@@ -2536,8 +2543,6 @@ static int ql_alloc_net_req_rsp_queues(struct ql3_adapter *qdev)

		return -ENOMEM;
	}

-	qdev->rsp_q_size = NUM_RSP_Q_ENTRIES * sizeof(struct net_rsp_iocb);
-
	qdev->rsp_q_virt_addr =
	    pci_alloc_consistent(qdev->pdev,
				 (size_t) qdev->rsp_q_size,