* [PATCH v3] mm/z3fold.c: Lock z3fold page before __SetPageMovable()
@ 2019-07-02 23:35 Henry Burns
2019-07-03 0:59 ` Shakeel Butt
0 siblings, 1 reply; 2+ messages in thread
From: Henry Burns @ 2019-07-02 23:35 UTC (permalink / raw)
To: Vitaly Wool, Andrew Morton
Cc: Vitaly Vul, Mike Rapoport, Xidong Wang, Shakeel Butt,
Jonathan Adams, linux-mm, linux-kernel, Henry Burns,
David Rientjes, stable
Following zsmalloc.c's example we call trylock_page() and unlock_page().
Also make z3fold_page_migrate() assert that newpage is passed in locked,
as per the documentation.
Link: http://lkml.kernel.org/r/20190702005122.41036-1-henryburns@google.com
Signed-off-by: Henry Burns <henryburns@google.com>
Suggested-by: Vitaly Wool <vitalywool@gmail.com>
Acked-by: Vitaly Wool <vitalywool@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Vitaly Vul <vitaly.vul@sony.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Xidong Wang <wangxidong_97@163.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
Changelog since v2:
- Removed the WARN_ON entirely, as it is an expected code path.
Changelog since v1:
- Added an if statement around WARN_ON(trylock_page(page)) to avoid
unlocking a page locked by a someone else.
mm/z3fold.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/mm/z3fold.c b/mm/z3fold.c
index e174d1549734..eeb3fe7f5ca3 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -918,7 +918,16 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
set_bit(PAGE_HEADLESS, &page->private);
goto headless;
}
- __SetPageMovable(page, pool->inode->i_mapping);
+ if (can_sleep) {
+ lock_page(page);
+ __SetPageMovable(page, pool->inode->i_mapping);
+ unlock_page(page);
+ } else {
+ if (!trylock_page(page)) {
+ __SetPageMovable(page, pool->inode->i_mapping);
+ unlock_page(page);
+ }
+ }
z3fold_page_lock(zhdr);
found:
@@ -1325,6 +1334,7 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa
VM_BUG_ON_PAGE(!PageMovable(page), page);
VM_BUG_ON_PAGE(!PageIsolated(page), page);
+ VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
zhdr = page_address(page);
pool = zhdr_to_pool(zhdr);
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v3] mm/z3fold.c: Lock z3fold page before __SetPageMovable()
2019-07-02 23:35 [PATCH v3] mm/z3fold.c: Lock z3fold page before __SetPageMovable() Henry Burns
@ 2019-07-03 0:59 ` Shakeel Butt
0 siblings, 0 replies; 2+ messages in thread
From: Shakeel Butt @ 2019-07-03 0:59 UTC (permalink / raw)
To: Henry Burns
Cc: Vitaly Wool, Andrew Morton, Vitaly Vul, Mike Rapoport,
Xidong Wang, Jonathan Adams, Linux MM, LKML, David Rientjes,
stable
On Tue, Jul 2, 2019 at 4:35 PM Henry Burns <henryburns@google.com> wrote:
>
> Following zsmalloc.c's example we call trylock_page() and unlock_page().
> Also make z3fold_page_migrate() assert that newpage is passed in locked,
> as per the documentation.
>
> Link: http://lkml.kernel.org/r/20190702005122.41036-1-henryburns@google.com
> Signed-off-by: Henry Burns <henryburns@google.com>
> Suggested-by: Vitaly Wool <vitalywool@gmail.com>
> Acked-by: Vitaly Wool <vitalywool@gmail.com>
> Acked-by: David Rientjes <rientjes@google.com>
> Cc: Shakeel Butt <shakeelb@google.com>
> Cc: Vitaly Vul <vitaly.vul@sony.com>
> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
> Cc: Xidong Wang <wangxidong_97@163.com>
> Cc: Jonathan Adams <jwadams@google.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We need a "Fixes" tag.
Reviewed-by: Shakeel Butt <shakeelb@google.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
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