block-map: add __GFP_ZERO flag for alloc_page in function bio_copy_kern

mainline inclusion
from mainline-v5.17-rc5
commit cc8f7fe1
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4Z2IA
CVE: CVE-2022-0494

--------------------------------

Add __GFP_ZERO flag for alloc_page in function bio_copy_kern to initialize
the buffer of a bio.
Signed-off-by: NHaimin Zhang <tcs.kernel@gmail.com>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220216084038.15635-1-tcs.kernel@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Conflict: commit ce288e05 ("block: remove BLK_BOUNCE_ISA support")
is not backported.
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

block/blk-map.c

@@ -488,7 +488,7 @@ static struct bio *bio_copy_kern(struct request_queue *q, void *data,
 		if (bytes > len)
 			bytes = len;
 
-		page = alloc_page(q->bounce_gfp | gfp_mask);
+		page = alloc_page(q->bounce_gfp | __GFP_ZERO | gfp_mask);
 		if (!page)
 			goto cleanup;