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| author | Peter Zijlstra <peterz@infradead.org> | 2020-10-19 12:13:53 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-10-19 09:32:28 -0600 |
| commit | 0669d2b265d0f6f9e16f1abbf5c5d2e22b219a6b (patch) | |
| tree | 6be6035e5b2230562ba0958969194486392bb32e /drivers/block/zram | |
| parent | db073272700fce69a9c41b27c62d0003dbb66488 (diff) | |
| download | linux-0669d2b265d0f6f9e16f1abbf5c5d2e22b219a6b.tar.bz2 | |
zram: Fix __zram_bvec_{read,write}() locking order
Mikhail reported a lockdep spat detailing how __zram_bvec_read() and
__zram_bvec_write() use zstrm->lock and zspage->lock in opposite order.
Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/zram')
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index bff3d4021c18..e13201424ba2 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1218,10 +1218,11 @@ out: static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, struct bio *bio, bool partial_io) { - int ret; + struct zcomp_strm *zstrm; unsigned long handle; unsigned int size; void *src, *dst; + int ret; zram_slot_lock(zram, index); if (zram_test_flag(zram, index, ZRAM_WB)) { @@ -1252,6 +1253,9 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, size = zram_get_obj_size(zram, index); + if (size != PAGE_SIZE) + zstrm = zcomp_stream_get(zram->comp); + src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO); if (size == PAGE_SIZE) { dst = kmap_atomic(page); @@ -1259,8 +1263,6 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, kunmap_atomic(dst); ret = 0; } else { - struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp); - dst = kmap_atomic(page); ret = zcomp_decompress(zstrm, src, size, dst); kunmap_atomic(dst); |