Re: [PATCH] qla3xxx: Ensure req_q_phy_addr writes to the register

On 10/18/12 01:45, Jitendra Kalsaria wrote:

quoted

-----Original Message-----
From: Joe Jin [mailto:joe.jin@oracle.com] 
Sent: Tuesday, October 16, 2012 11:32 PM
To: Ron Mercer; Jitendra Kalsaria; Dept-Eng Linux Driver
Cc: netdev; linux-kernel; Greg Marsden
Subject: [PATCH] qla3xxx: Ensure req_q_phy_addr writes to the register

Make sure req_q_phy_addr write to the register.

Signed-off-by: Joe Jin <redacted>
Cc: Ron Mercer <redacted>
Cc: Jitendra Kalsaria <redacted>
---
drivers/net/ethernet/qlogic/qla3xxx.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/qlogic/qla3xxx.c b/drivers/net/ethernet/qlogic/qla3xxx.c
index df09b1c..78b4cba 100644
--- a/drivers/net/ethernet/qlogic/qla3xxx.c
+++ b/drivers/net/ethernet/qlogic/qla3xxx.c

@@ -2525,6 +2525,12 @@ 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));

+	/*
+	 * The barrier is required to ensure that req_q_phy_addr writes to
+	 * the memory.
+	 */
+	wmb();
+
	qdev->req_q_virt_addr =
	    pci_alloc_consistent(qdev->pdev,
				 (size_t) qdev->req_q_size,

Your changes only take care of request queue but not response queue which also need barrier.

Jiten,

Thanks for review!
The barrier to make sure writel() call for req_q_phy_addr and rsp_q_phy_addr in 
ql_adapter_initialize(), so I think call once wmb() is enough but I need to update
the comment, any idea?

Thanks,
Joe

	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);

	wmb();

thanks,
	Jiten

-- 
Oracle <http://www.oracle.com>
Joe Jin | Software Development Senior Manager | +8610.6106.5624
ORACLE | Linux and Virtualization
No. 24 Zhongguancun Software Park, Haidian District | 100193 Beijing