• Mike Snitzer's avatar
    block: disable entropy contributions for nonrot devices · b277da0a
    Mike Snitzer authored
    Clear QUEUE_FLAG_ADD_RANDOM in all block drivers that set
    QUEUE_FLAG_NONROT.
    
    Historically, all block devices have automatically made entropy
    contributions.  But as previously stated in commit e2e1a148 ("block: add
    sysfs knob for turning off disk entropy contributions"):
        - On SSD disks, the completion times aren't as random as they
          are for rotational drives. So it's questionable whether they
          should contribute to the random pool in the first place.
        - Calling add_disk_randomness() has a lot of overhead.
    
    There are more reliable sources for randomness than non-rotational block
    devices.  From a security perspective it is better to err on the side of
    caution than to allow entropy contributions from unreliable "random"
    sources.
    Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
    Signed-off-by: default avatarJens Axboe <axboe@fb.com>
    b277da0a
null_blk.c 13.2 KB