From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jun'ichi Nomura <j-nomura@ce.jp.nec.com>,
Matt Mackall <mpm@selenic.com>
Subject: Re: [BUGFIX][PATCH] pagemap: set pagemap walk limit to PMD boundary
Date: Mon, 22 Nov 2010 13:09:54 +0900 [thread overview]
Message-ID: <20101122040953.GB3017@spritzera.linux.bs1.fc.nec.co.jp> (raw)
In-Reply-To: <20101122120102.e0e76373.kamezawa.hiroyu@jp.fujitsu.com>
> > @@ -776,7 +777,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
> > unsigned long end;
> >
> > pm.pos = 0;
> > - end = start_vaddr + PAGEMAP_WALK_SIZE;
> > + end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
> > /* overflow ? */
> > if (end < start_vaddr || end > end_vaddr)
> > end = end_vaddr;
>
> Ack.
>
> But ALIGN() can't be used ?
ALIGN() returns the same address as the input if it is already aligned,
but what we need here is the next PMD boundary. So something like
end = IS_ALIGNED(start_vaddr, PAGEMAP_WALK_SIZE) ?
start_vaddr + PAGEMAP_WALK_SIZE :
ALIGN(start_vaddr, PAGEMAP_WALK_SIZE)
keeps the semantics, but I don't like it because it's lengthy.
Anyway, thanks for your comment.
Naoya Horiguchi
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prev parent reply other threads:[~2010-11-22 4:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-19 9:07 Naoya Horiguchi
2010-11-22 3:01 ` KAMEZAWA Hiroyuki
2010-11-22 4:09 ` Naoya Horiguchi [this message]
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