erofs: fix kvcalloc() misuse with __GFP_NOFAIL

As reported by syzbot [1], kvcalloc() cannot work with  __GFP_NOFAIL.
Let's use kcalloc() instead.

[1] https://lore.kernel.org/r/0000000000007796bd05f1852ec2@google.com

Reported-by: syzbot+c3729cda01706a04fb98@syzkaller.appspotmail.com
Fixes: fe3e5914 ("erofs: try to leave (de)compressed_pages on stack if possible")
Fixes: 4f05687f ("erofs: introduce struct z_erofs_decompress_backend")
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230110074927.41651-1-hsiangkao@linux.alibaba.com

fs/erofs/zdata.c

@@ -1032,11 +1032,11 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
 
 	if (!be->decompressed_pages)
 		be->decompressed_pages =
-			kvcalloc(be->nr_pages, sizeof(struct page *),
+			kcalloc(be->nr_pages, sizeof(struct page *),
 				GFP_KERNEL | __GFP_NOFAIL);
 	if (!be->compressed_pages)
 		be->compressed_pages =
-			kvcalloc(pclusterpages, sizeof(struct page *),
+			kcalloc(pclusterpages, sizeof(struct page *),
 				GFP_KERNEL | __GFP_NOFAIL);
 
 	z_erofs_parse_out_bvecs(be);
@@ -1085,7 +1085,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
 	}
 	if (be->compressed_pages < be->onstack_pages ||
 	    be->compressed_pages >= be->onstack_pages + Z_EROFS_ONSTACK_PAGES)
-		kvfree(be->compressed_pages);
+		kfree(be->compressed_pages);
 	z_erofs_fill_other_copies(be, err);
 
 	for (i = 0; i < be->nr_pages; ++i) {
@@ -1104,7 +1104,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
 	}
 
 	if (be->decompressed_pages != be->onstack_pages)
-		kvfree(be->decompressed_pages);
+		kfree(be->decompressed_pages);
 
 	pcl->length = 0;
 	pcl->partial = true;