zsmalloc: zs_malloc: return ERR_PTR on failure

zs_malloc returns 0 if it fails.  zs_zpool_malloc will return -1 when
zs_malloc return 0.  But -1 makes the return value unclear.

For example, when zswap_frontswap_store calls zs_malloc through
zs_zpool_malloc, it will return -1 to its caller.  The other return value
is -EINVAL, -ENODEV or something else.

This commit changes zs_malloc to return ERR_PTR on failure.  It didn't
just let zs_zpool_malloc return -ENOMEM becaue zs_malloc has two types of
failure:

- size is not OK return -EINVAL
- memory alloc fail return -ENOMEM.

Link: https://lkml.kernel.org/r/20220714080757.12161-1-teawater@gmail.com
Signed-off-by: Hui Zhu <teawater@antgroup.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 3e281a193feb..9d3b06d5dc56 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1389,9 +1389,9 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
 			__GFP_HIGHMEM |
 			__GFP_MOVABLE);
 
-	if (unlikely(!handle)) {
+	if (IS_ERR((void *)handle)) {
 		zcomp_stream_put(zram->comp);
-		return -ENOMEM;
+		return PTR_ERR((void *)handle);
 	}
 
 	alloced_pages = zs_get_total_pages(zram->mem_pool);