From b277da0a8a594308e17881f4926879bd5fca2a2d Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Sat, 4 Oct 2014 10:55:32 -0600 Subject: 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 --- drivers/block/mtip32xx/mtip32xx.c | 1 + drivers/block/nbd.c | 1 + drivers/block/null_blk.c | 1 + drivers/block/nvme-core.c | 1 + drivers/block/rsxx/dev.c | 1 + drivers/block/skd_main.c | 1 + drivers/block/zram/zram_drv.c | 1 + 7 files changed, 7 insertions(+) (limited to 'drivers/block') 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); diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index fb31b8ee4372..4bc2a5cb9935 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -847,6 +847,7 @@ static int __init nbd_init(void) * Tell the block layer that we are not a rotational device */ queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue); disk->queue->limits.discard_granularity = 512; disk->queue->limits.max_discard_sectors = UINT_MAX; disk->queue->limits.discard_zeroes_data = 0; diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index a3b042c4d448..b0d94b6973ab 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -507,6 +507,7 @@ static int null_add_dev(void) nullb->q->queuedata = nullb; queue_flag_set_unlocked(QUEUE_FLAG_NONROT, nullb->q); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, nullb->q); disk = nullb->disk = alloc_disk_node(1, home_node); if (!disk) diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c index 02351e217165..e2bb8afbeae5 100644 --- a/drivers/block/nvme-core.c +++ b/drivers/block/nvme-core.c @@ -1916,6 +1916,7 @@ static struct nvme_ns *nvme_alloc_ns(struct nvme_dev *dev, unsigned nsid, ns->queue->queue_flags = QUEUE_FLAG_DEFAULT; queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, ns->queue); queue_flag_set_unlocked(QUEUE_FLAG_NONROT, ns->queue); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, ns->queue); blk_queue_make_request(ns->queue, nvme_make_request); ns->dev = dev; ns->queue->queuedata = ns; diff --git a/drivers/block/rsxx/dev.c b/drivers/block/rsxx/dev.c index 2839d37e5af7..40ee7705df63 100644 --- a/drivers/block/rsxx/dev.c +++ b/drivers/block/rsxx/dev.c @@ -307,6 +307,7 @@ int rsxx_setup_dev(struct rsxx_cardinfo *card) blk_queue_physical_block_size(card->queue, RSXX_HW_BLK_SIZE); queue_flag_set_unlocked(QUEUE_FLAG_NONROT, card->queue); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, card->queue); if (rsxx_discard_supported(card)) { queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, card->queue); blk_queue_max_discard_sectors(card->queue, diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c index 8fcdcfb4b472..1e46eb2305c0 100644 --- a/drivers/block/skd_main.c +++ b/drivers/block/skd_main.c @@ -4426,6 +4426,7 @@ static int skd_cons_disk(struct skd_device *skdev) q->limits.discard_zeroes_data = 1; queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q); spin_lock_irqsave(&skdev->lock, flags); pr_debug("%s:%s:%d stopping %s queue\n", diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index dfa4024c448a..6dd2cef5b865 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -925,6 +925,7 @@ static int create_device(struct zram *zram, int device_id) set_capacity(zram->disk, 0); /* zram devices sort of resembles non-rotational disks */ queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, zram->disk->queue); /* * To ensure that we always get PAGE_SIZE aligned * and n*PAGE_SIZED sized I/O requests. -- cgit v1.2.3