From: Mike Snitzer Date: Sat, 4 Oct 2014 16:55:32 +0000 (-0600) Subject: block: disable entropy contributions for nonrot devices X-Git-Tag: fixes-against-v3.18-rc2~52^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b277da0a8a59;p=pandora-kernel.git 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 Signed-off-by: Jens Axboe --- diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c index db1e9560d8a7..936f8c160e46 100644 --- a/drivers/block/mtip32xx/mtip32xx.c +++ b/drivers/block/mtip32xx/mtip32xx.c @@ -3952,6 +3952,7 @@ skip_create_disk: /* Set device limits. */ set_bit(QUEUE_FLAG_NONROT, &dd->queue->queue_flags); + clear_bit(QUEUE_FLAG_ADD_RANDOM, &dd->queue->queue_flags); blk_queue_max_segments(dd->queue, MTIP_MAX_SG); blk_queue_physical_block_size(dd->queue, 4096); blk_queue_max_hw_sectors(dd->queue, 0xffff); Reading git-diff-tree failed