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Subject[PATCH] block:zram: do not keep dangling zcomp pointer after zram reset
Date
We do all reset operations under write lock, so we don't need
to save ->disksize and ->comp to stack variables. Another thing
is that ->comp is freed during zram reset, but comp pointer is
not NULL-ed, so zram keeps the freed pointer value.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
drivers/block/zram/zram_drv.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 0c8c211f051f..4fc99c5667ef 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1721,9 +1721,6 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,

static void zram_reset_device(struct zram *zram)
{
- struct zcomp *comp;
- u64 disksize;
-
down_write(&zram->init_lock);

zram->limit_pages = 0;
@@ -1733,17 +1730,15 @@ static void zram_reset_device(struct zram *zram)
return;
}

- comp = zram->comp;
- disksize = zram->disksize;
- zram->disksize = 0;
-
set_capacity_and_notify(zram->disk, 0);
part_stat_set_all(zram->disk->part0, 0);

/* I/O operation under all of CPU are done so let's free */
- zram_meta_free(zram, disksize);
+ zram_meta_free(zram, zram->disksize);
+ zram->disksize = 0;
memset(&zram->stats, 0, sizeof(zram->stats));
- zcomp_destroy(comp);
+ zcomp_destroy(zram->comp);
+ zram->comp = NULL;
reset_bdev(zram);

up_write(&zram->init_lock);
--
2.37.2.609.g9ff673ca1a-goog
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