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Date:   Thu, 23 May 2019 10:01:54 -0400 (EDT)
From:   Alan Stern <stern@rowland.harvard.edu>
To:     Oliver Neukum <oneukum@suse.com>
cc:     Jaewon Kim <jaewon31.kim@gmail.com>,
        Christoph Hellwig <hch@infradead.org>, <linux-mm@kvack.org>,
        <gregkh@linuxfoundation.org>,
        Jaewon Kim <jaewon31.kim@samsung.com>,
        <m.szyprowski@samsung.com>, <ytk.lee@samsung.com>,
        <linux-kernel@vger.kernel.org>, <linux-usb@vger.kernel.org>
Subject: Re: [RFC PATCH] usb: host: xhci: allow __GFP_FS in dma allocation
In-Reply-To: <1558558075.2470.2.camel@suse.com>
Message-ID: <Pine.LNX.4.44L0.1905231001100.1553-100000@iolanthe.rowland.org>
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On Wed, 22 May 2019, Oliver Neukum wrote:

> On Mi, 2019-05-22 at 10:56 -0400, Alan Stern wrote:
> > On Wed, 22 May 2019, Oliver Neukum wrote:
> > 
> > > I agree with the problem, but I fail to see why this issue would be
> > > specific to USB. Shouldn't this be done in the device core layer?
> > 
> > Only for drivers that are on the block-device writeback path.  The 
> > device core doesn't know which drivers these are.
> 
> Neither does USB know. It is very hard to predict or even tell which
> devices are block device drivers. I think we must assume that
> any device may be affected.

All right.  Would you like to submit a patch?

Alan Stern