Re: [PATCH] ib_srpt: Add missing ioctx->buf + ->dma alloc_session_cb init

[Bart Van Assche <bart.vanassche@sandisk.com>]

On 04/04/2016 03:41 PM, Nicholas A. Bellinger wrote:
> On Mon, 2016-04-04 at 11:40 -0700, Bart Van Assche wrote:
>> On 04/04/2016 11:28 AM, Nicholas A. Bellinger wrote:
>>> diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
>>> index 0bd3cb2..c4e0a0a 100644
>>> --- a/drivers/infiniband/ulp/srpt/ib_srpt.c
>>> +++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
>>> @@ -1266,7 +1266,9 @@ static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
>>>    {
>>>    	struct se_session *se_sess;
>>>    	struct srpt_send_ioctx *ioctx;
>>> -	int tag;
>>> +	void *buf;
>>> +	dma_addr_t dma;
>>> +	int tag, index;
>>>
>>>    	BUG_ON(!ch);
>>>    	se_sess = ch->sess;
>>> @@ -1277,12 +1279,19 @@ static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
>>>    		return NULL;
>>>    	}
>>>    	ioctx = &((struct srpt_send_ioctx *)se_sess->sess_cmd_map)[tag];
>>> +	buf = ioctx->ioctx.buf;
>>> +	dma = ioctx->ioctx.dma;
>>> +	index = ioctx->ioctx.index;
>>> +
>>>    	memset(ioctx, 0, sizeof(struct srpt_send_ioctx));
>>>    	ioctx->ch = ch;
>>>    	spin_lock_init(&ioctx->spinlock);
>>>    	ioctx->state = SRPT_STATE_NEW;
>>>    	init_completion(&ioctx->tx_done);
>>>
>>> +	ioctx->ioctx.buf = buf;
>>> +	ioctx->ioctx.dma = dma;
>>> +	ioctx->ioctx.index = index;
>>>    	ioctx->cmd.map_tag = tag;
>>>
>>>    	return ioctx;
>>> @@ -1961,6 +1970,24 @@ static void srpt_free_ch(struct kref *kref)
>>>    	kfree(ch);
>>>    }
>>
>> These assignments should happen once, namely just after I/O context
>> allocation, instead of performing these assignments during every
>> srpt_get_send_ioctx() call.
>
> No, the entire structure is being cleared each time, just like what
> every other driver is doing here.
>
> Don't try to micro-optimize to avoid doing memset.

But why to keep that memset(ioctx, ...) call? That memset() call is new. 
It was added during the 4.6-rc1 merge window.

Bart.