random: export add_disk_randomness

This will be needed for pending changes to the scsi midlayer that now
calls lower level block APIs, as well as any blk-mq driver that wants to
contribute to the random pool.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NJens Axboe <axboe@fb.com>

drivers/char/random.c

@@ -902,6 +902,7 @@ void add_disk_randomness(struct gendisk *disk)
 	add_timer_randomness(disk->random, 0x100 + disk_devt(disk));
 	trace_add_disk_randomness(disk_devt(disk), ENTROPY_BITS(&input_pool));
 }
+EXPORT_SYMBOL_GPL(add_disk_randomness);
 #endif
 
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