[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20210226205139.GI2723601@casper.infradead.org>
Date: Fri, 26 Feb 2021 20:51:39 +0000
From: Matthew Wilcox <willy@...radead.org>
To: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] Fix zero_user_segments() with start > end
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@...r.kernel.org>
> Signed-off-by: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
Fixes: 0060ef3b4e6d ("mm: support THPs in zero_user_segments")
Powered by blists - more mailing lists