linux-kernel - Re: [PATCH] regmap: Allocate buffers with GFP_ATOMIC when fast

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Message-ID: <20150911102858.GE12027@sirena.org.uk>
Date:	Fri, 11 Sep 2015 11:28:58 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Stephen Boyd <sboyd@...eaurora.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] regmap: Allocate buffers with GFP_ATOMIC when fast_io ==
 true

On Thu, Sep 10, 2015 at 12:27:01PM -0700, Stephen Boyd wrote:
> If a regmap is using fast_io, allocate buffers in the write APIs
> with GFP_ATOMIC instead of GFP_KERNEL. Otherwise we may schedule
> while atomic.

Why is this needed?  If something needs fast I/O it probably doesn't
want to be going down any of the code paths that result in us doing
allocations.  I'd expect either no cache, a flat cache or setting up
defaults at initialisation time.

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