From: Andrew Morton <akpm@linux-foundation.org>
To: Yu Zhao <yuzhao@google.com>
Cc: Hugh Dickins <hughd@google.com>,
Matthew Wilcox <willy@infradead.org>,
stable@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm: use swp_offset as key in shmem_replace_page()
Date: Wed, 21 Nov 2018 21:01:59 -0800 [thread overview]
Message-ID: <20181121210159.3a5fb6946e460c561fdec391@linux-foundation.org> (raw)
In-Reply-To: <20181121215442.138545-1-yuzhao@google.com>
On Wed, 21 Nov 2018 14:54:42 -0700 Yu Zhao <yuzhao@google.com> wrote:
> We changed key of swap cache tree from swp_entry_t.val to
> swp_offset. Need to do so in shmem_replace_page() as well.
What are the user-visible effects of this change?
> Fixes: f6ab1f7f6b2d ("mm, swap: use offset of swap entry as key of swap cache")
> Cc: stable@vger.kernel.org # v4.9+
Please always provide the user-impact information when fixing bugs. This
becomes especially important when proposing -stable backporting.
Hugh said
: shmem_replace_page() has been wrong since the day I wrote it: good
: enough to work on swap "type" 0, which is all most people ever use
: (especially those few who need shmem_replace_page() at all), but broken
: once there are any non-0 swp_type bits set in the higher order bits.
but we still don't have a description of "broken".
Thanks.
next prev parent reply other threads:[~2018-11-22 5:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-19 0:47 [PATCH] mm: fix swap offset when replacing shmem page Yu Zhao
2018-11-19 1:09 ` [PATCH v2] " Yu Zhao
2018-11-19 22:11 ` Hugh Dickins
2018-11-20 1:29 ` Yu Zhao
2018-11-20 5:07 ` Hugh Dickins
2018-11-20 13:12 ` Matthew Wilcox
2018-11-21 21:54 ` [PATCH v3] mm: use swp_offset as key in shmem_replace_page() Yu Zhao
2018-11-21 22:11 ` Matthew Wilcox
2018-11-22 0:36 ` Hugh Dickins
2018-11-22 5:01 ` Andrew Morton [this message]
2018-11-23 20:11 ` Hugh Dickins
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