Re: [PATCH v2 0/3] new ib_drain_qp() API

From: Sagi Grimberg <sagig-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
To: Bart Van Assche
	<bart.vanassche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>,
	Steve Wise
	<swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>,
	"linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Cc: 'Sagi Grimberg' <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>,
	'Christoph Hellwig' <hch-jcswGhMUV9g@public.gmane.org>,
	'Chuck Lever'
	<chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH v2 0/3] new ib_drain_qp() API
Date: Thu, 11 Feb 2016 12:46:30 +0200	[thread overview]
Message-ID: <56BC6686.8030301@dev.mellanox.co.il> (raw)
In-Reply-To: <56BB4479.8090009-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>


>> I'd suggest to look at the CQ context and act accordingly, something
>> like:
>>
>>     if (cq->poll_ctx == IB_POLL_DIRECT) {
>>         while (!wait_for_completion_timeout(&sdrain.done,
>>                 mescs_to_jiffies(100))
>>             ib_process_cq_direct(cq, 1024)
>>     } else {
>>         wait_for_completion(&sdrain.done);
>>     }
>>
>> Thoughts?
>
> Hello Sagi,
>
> The above code will only work as expected if the caller won't call
> ib_process_cq_direct() for the same queue from another context.

Why? ib_poll_cq is safe from multiple contexts. Is it because the
completion structures are on stack? because if so we can easily move
them to the cq...
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