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

From: Joe Jin <[email-masked]>
Date: Thu, 18 Oct 2012 10:18:07 +0800

On 10/18/12 01:45, Jitendra Kalsaria wrote:
> 
> 
>> -----Original Message-----
>> From: Joe Jin [mailto:[email-masked]] 
>> 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 <[email-masked]>
>> Cc: Ron Mercer <[email-masked]>
>> Cc: Jitendra Kalsaria <[email-masked]>
>> ---
>> 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
> 

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