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Date: Fri, 3 Oct 2014 18:58:56 -0400
From: Mike Snitzer <snitzer@...hat.com>
To: axboe@...nel.dk, linux-kernel@...r.kernel.org
Cc: tytso@....edu, gmazyland@...il.com, agk@...hat.com,
mpatocka@...hat.com
Subject: [PATCH v2] 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@...hat.com>
---
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 +
drivers/ide/ide-disk.c | 4 +++-
drivers/md/bcache/super.c | 1 +
drivers/mmc/card/queue.c | 1 +
drivers/mtd/mtd_blkdevs.c | 1 +
drivers/s390/block/scm_blk.c | 1 +
drivers/s390/block/xpram.c | 1 +
drivers/scsi/sd.c | 4 +++-
14 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 5c8e7fe..6134caf 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3951,6 +3951,7 @@ 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 fb31b8e..4bc2a5c 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 00d469c..c71e1b0 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -518,6 +518,7 @@ 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 02351e2..e2bb8af 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 2839d37..40ee770 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 8fcdcfb..1e46eb2 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 d00831c..0e0f51c 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -929,6 +929,7 @@ 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.
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index ee88038..56b9708 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);
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index d4713d0..4dd2bb7 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -842,6 +842,7 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
q->limits.logical_block_size = block_size;
q->limits.physical_block_size = block_size;
set_bit(QUEUE_FLAG_NONROT, &d->disk->queue->queue_flags);
+ clear_bit(QUEUE_FLAG_ADD_RANDOM, &d->disk->queue->queue_flags);
set_bit(QUEUE_FLAG_DISCARD, &d->disk->queue->queue_flags);
blk_queue_flush(q, REQ_FLUSH|REQ_FUA);
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 3e049c1..c19bfc1 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -210,6 +210,7 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
blk_queue_prep_rq(mq->queue, mmc_prep_request);
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
+ queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, mq->queue);
if (mmc_can_erase(card))
mmc_queue_setup_discard(mq->queue, card);
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 43e3099..d08229e 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -417,6 +417,7 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
blk_queue_logical_block_size(new->rq, tr->blksize);
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq);
+ queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq);
if (tr->discard) {
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
diff --git a/drivers/s390/block/scm_blk.c b/drivers/s390/block/scm_blk.c
index 76bed17..56046ab 100644
--- a/drivers/s390/block/scm_blk.c
+++ b/drivers/s390/block/scm_blk.c
@@ -386,6 +386,7 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */
blk_queue_max_segments(rq, nr_max_blk);
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq);
+ queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, rq);
scm_blk_dev_cluster_setup(bdev);
bdev->gendisk = alloc_disk(SCM_NR_PARTS);
diff --git a/drivers/s390/block/xpram.c b/drivers/s390/block/xpram.c
index 6969d39..9e0de9c 100644
--- a/drivers/s390/block/xpram.c
+++ b/drivers/s390/block/xpram.c
@@ -346,6 +346,7 @@ static int __init xpram_setup_blkdev(void)
goto out;
}
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, xpram_queues[i]);
+ queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, xpram_queues[i]);
blk_queue_make_request(xpram_queues[i], xpram_make_request);
blk_queue_logical_block_size(xpram_queues[i], 4096);
}
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 2c2041c..fe67f5c 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2660,8 +2660,10 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
rot = get_unaligned_be16(&buffer[4]);
- if (rot == 1)
+ if (rot == 1) {
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, sdkp->disk->queue);
+ queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, sdkp->disk->queue);
+ }
out:
kfree(buffer);
--
1.7.4.4
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