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| author | Mike Snitzer <snitzer@redhat.com> | 2014-10-04 10:55:32 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-10-04 10:55:32 -0600 |
| commit | b277da0a8a594308e17881f4926879bd5fca2a2d (patch) | |
| tree | 1af7df6ade218a4b246dd43a0771701a672c6cb8 /drivers/ide | |
| parent | 7b7b7f7e024460cb7d77f8f96b6eb1a8803f94d9 (diff) | |
| download | linux-stable-b277da0a8a594308e17881f4926879bd5fca2a2d.tar.gz linux-stable-b277da0a8a594308e17881f4926879bd5fca2a2d.tar.bz2 linux-stable-b277da0a8a594308e17881f4926879bd5fca2a2d.zip | |
block: disable entropy contributions for nonrot devices
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: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/ide')
| -rw-r--r-- | drivers/ide/ide-disk.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c index ee880382e3bc..56b9708894a5 100644 --- a/drivers/ide/ide-disk.c +++ b/drivers/ide/ide-disk.c @@ -685,8 +685,10 @@ static void ide_disk_setup(ide_drive_t *drive) printk(KERN_INFO "%s: max request size: %dKiB\n", drive->name, queue_max_sectors(q) / 2); - if (ata_id_is_ssd(id)) + if (ata_id_is_ssd(id)) { queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q); + } /* calculate drive capacity, and select LBA if possible */ ide_disk_get_capacity(drive); |