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

From: Jitendra Kalsaria
Date: Thu Oct 18 2012 - 13:10:41 EST




>>> -----Original Message-----
>>> From: Joe Jin [mailto:joe.jin@xxxxxxxxxx]
>>> 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 <joe.jin@xxxxxxxxxx>
>>> Cc: Ron Mercer <ron.mercer@xxxxxxxxxx>
>>> Cc: Jitendra Kalsaria <jitendra.kalsaria@xxxxxxxxxx>
>>> ---
>>> 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?

Yes and something like "ensure request/response queue addr writes to the register"

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