block: add bdev_max_segments() helper

Add bdev_max_segments() like other queue parameters.
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

include/linux/blkdev.h

@@ -1206,6 +1206,11 @@ bdev_max_zone_append_sectors(struct block_device *bdev)
 	return queue_max_zone_append_sectors(bdev_get_queue(bdev));
 }
 
+static inline unsigned int bdev_max_segments(struct block_device *bdev)
+{
+	return queue_max_segments(bdev_get_queue(bdev));
+}
+
 static inline unsigned queue_logical_block_size(const struct request_queue *q)
 {
 	int retval = 512;