The patch titled
Subject: zram: revalidate disk under init_lock
has been added to the -mm tree. Its filename is
zram-revalidate-disk-under-init_lock.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/zram-revalidate-disk-under-init_lock.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/zram-revalidate-disk-under-init_lock.patch
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------------------------------------------------------
From: Minchan Kim <minchan@xxxxxxxxxx>
Subject: zram: revalidate disk under init_lock
[1] moved revalidate_disk call out of init_lock to avoid lockdep
false-positive splat. However, [2] remove init_lock in IO path
so there is no worry about lockdep splat. So, let's restore it.
This patch need to set BDI_CAP_STABLE_WRITES atomically in
next patch.
[1] b4c5c60920e3: zram: avoid lockdep splat by revalidate_disk
[2] 08eee69fcf6b: zram: remove init_lock in zram_make_request
Fixes: da9556a2367c ("zram: user per-cpu compression streams")
Link: http://lkml.kernel.org/r/1482366980-3782-3-git-send-email-minchan@xxxxxxxxxx
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxx>
Cc: Hyeoncheol Lee <cheol.lee@xxxxxxx>
Cc: <yjay.kim@xxxxxxx>
Cc: Sangseok Lee <sangseok.lee@xxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [4.7+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff -puN drivers/block/zram/zram_drv.c~zram-revalidate-disk-under-init_lock drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-revalidate-disk-under-init_lock
+++ a/drivers/block/zram/zram_drv.c
@@ -1095,14 +1095,8 @@ static ssize_t disksize_store(struct dev
zram->comp = comp;
zram->disksize = disksize;
set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
- up_write(&zram->init_lock);
-
- /*
- * Revalidate disk out of the init_lock to avoid lockdep splat.
- * It's okay because disk's capacity is protected by init_lock
- * so that revalidate_disk always sees up-to-date capacity.
- */
revalidate_disk(zram->disk);
+ up_write(&zram->init_lock);
return len;
_
Patches currently in -mm which might be from minchan@xxxxxxxxxx are
mm-pmd-dirty-emulation-in-page-fault-handler.patch
mm-support-anonymous-stable-page.patch
zram-revalidate-disk-under-init_lock.patch
zram-support-bdi_cap_stable_writes.patch
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