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Date: Wed, 27 Jul 2016 15:23:08 -0400
From: Tejun Heo <tj@kernel.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oneukum@suse.com>,
        Bhaktipriya Shridhar <bhaktipriya96@gmail.com>,
        Geliang Tang <geliangtang@163.com>,
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        Saurabh Karajgaonkar <skarajga@visteon.com>,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [RFC] usb: host: u132-hcd: Remove deprecated
 create_singlethread_workqueue
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Hello, Alan.

On Wed, Jul 27, 2016 at 02:54:51PM -0400, Alan Stern wrote:
> > Hmm... I didn't know the whole USB stack could operate without
> > allocating memory.  Does usb stack have mempools and stuff all the way
> > through?
> 
> No -- the USB stack does need to allocate memory in order to operate.  
> But it is careful to use GFP_NOIO or GFP_ATOMIC for allocations that
> might be on the block-device path.

Hmm... That doesn't really make them dependable during memory reclaim.
What happens when those allocations fail?

Thanks.

-- 
tejun