linux-kernel - Re: [PATCH 2/2] efi: Capsule update support

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Message-ID: <20141014214633.GD14343@console-pimps.org>
Date:	Tue, 14 Oct 2014 22:46:33 +0100
From:	Matt Fleming <matt@...sole-pimps.org>
To:	Borislav Petkov <bp@...en8.de>
Cc:	linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
	Matt Fleming <matt.fleming@...el.com>,
	Leif Lindholm <leif.lindholm@...aro.org>,
	"Kweh, Hock Leong" <hock.leong.kweh@...el.com>
Subject: Re: [PATCH 2/2] efi: Capsule update support

On Fri, 10 Oct, at 08:28:47PM, Borislav Petkov wrote:
> 
> You have efi_capsule_update() vs efi_update_capsule(). Maybe change the
> names a bit more for differentiation. Or prepend the workhorse doing all
> the work with "__" or so...
 
Yeah, I really didn't come up with a great naming scheme here. I'll fix
that.

> > +
> > +	for (i = 0; i < nr_block_pgs; i++) {
> > +		block_pgs[i] = alloc_page(GFP_KERNEL);
> 
> Maybe alloc_pages() once we verify that it actually gives phys. contig.
> memory and maybe also try to do it outside of the locked region. I don't
> know if it would matter to drop the locks though as capsule updating is
> not something you do pretty often. I'd hope!

Actually, I'm not bothered about getting physically contiguous memory
because we pass a scatter gather list to the firmware anyway. What I was
looking for was to avoid doing high order allocations when we don't
really need them (lots of low order allocs are fine).

Right, allocating under the lock isn't a great idea. I'll take a look at
reworking this to do the allocation up front.

-- 
Matt Fleming, Intel Open Source Technology Center
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