block: export blk_next_bio()

The block layer provides emulation of zone management operations targeting all zones of a zoned block device only for the zone reset operation (REQ_OP_ZONE_RESET). In order to correctly implement exporting of zoned block devices with NVMeOF, emulating zone management operations targeting all zones of a device is also necessary for the open, close and finish zone operations (REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH). Instead of duplicating the code, export the existing helper from block layer so we can use a bio chaining pattern that is present in the block layer for REQ_OP_ZONE RESET all emulation in the NVMeOF zoned block device backend. Reviewed-by: Damien Le Moal <[email protected]> Signed-off-by: Chaitanya Kulkarni <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]>
kawasaki · Jun 17, 2021 · c28a614 · c28a614
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commit c28a614
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diff --git a/block/blk-lib.c b/block/blk-lib.c
@@ -21,6 +21,7 @@ struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp)
 
 	return new;
 }
+EXPORT_SYMBOL_GPL(blk_next_bio);
 
 int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp_mask, int flags,

diff --git a/include/linux/bio.h b/include/linux/bio.h
@@ -822,4 +822,6 @@ static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
 		bio->bi_opf |= REQ_NOWAIT;
 }
 
+struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp);
+
 #endif /* __LINUX_BIO_H */