From: Matthew Wilcox <willy@infradead.org>
To: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] Fix zero_user_segments() with start > end
Date: Fri, 26 Feb 2021 20:51:39 +0000 [thread overview]
Message-ID: <20210226205139.GI2723601@casper.infradead.org> (raw)
In-Reply-To: <87eeh2erm0.fsf@mail.parknet.co.jp>
On Sat, Feb 27, 2021 at 01:11:35AM +0900, OGAWA Hirofumi wrote:
> zero_user_segments() is used from __block_write_begin_int(), for
> example like the following
>
> zero_user_segments(page, 4096, 1024, 512, 918)
>
> But new zero_user_segments() implements for HIGMEM + TRANSPARENT_HUGEPAGE
> doesn't handle "start > end" case correctly, and hits BUG_ON(). (we
> can fix __block_write_begin_int() instead though, it is the old and
> multiple usage)
Why don't we just take out the BUG_ON instead? The function doesn't
actually do the wrong thing.
> Also it calls kmap_atomic() unnecessary while start == end == 0.
I'm OK with that. It always used to do that.
> Cc: <stable@vger.kernel.org>
> Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Fixes: 0060ef3b4e6d ("mm: support THPs in zero_user_segments")
next prev parent reply other threads:[~2021-02-26 20:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 16:11 [PATCH] Fix zero_user_segments() with start > end OGAWA Hirofumi
2021-02-26 20:51 ` Matthew Wilcox [this message]
2021-02-27 3:36 ` OGAWA Hirofumi
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