Re: [PATCH 03/14] resource: add walk_system_ram_res_rev()

From: AKASHI Takahiro <takahiro.akashi@linaro.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>,
	David Howells <dhowells@redhat.com>,
	Vivek Goyal <vgoyal@redhat.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Dave Young <dyoung@redhat.com>, Baoquan He <bhe@redhat.com>,
	Arnd Bergmann <arnd@arndb.de>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 03/14] resource: add walk_system_ram_res_rev()
Date: Fri, 25 Aug 2017 09:50:07 +0900	[thread overview]
Message-ID: <20170825005006.GB6434@akashi-kouhiroshi-no-MacBook-Air.local> (raw)
In-Reply-To: <CAKv+Gu_UfeDf13RPUejVqz0y=QjSCGhPn6fTTCyLWHY=iu-4BA@mail.gmail.com>

On Thu, Aug 24, 2017 at 10:06:28AM +0100, Ard Biesheuvel wrote:
> On 24 August 2017 at 09:18, AKASHI Takahiro <takahiro.akashi@linaro.org> wrote:
> > +       /* create a list */
> > +       rams = vmalloc(sizeof(struct resource) * count);
> > +       if (!rams)
> > +               return ret;
> > +
> > +       res.start = start;
> > +       res.end = end;
> > +       res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> > +       orig_end = res.end;
> > +       i = 0;
> > +       while ((res.start < res.end) &&
> > +               (!find_next_iomem_res(&res, IORES_DESC_NONE, true))) {
> > +               if (i >= count) {
> > +                       /* unlikely but */
> > +                       vfree(rams);
> > +                       count += 16;
> 
> If the count is likely to be < 16, why are we using vmalloc() here?

Ah, you're right :)

-Takahiro AKASHI