linux-kernel - [RFC PATCH v1 41/50] drivers/block/drbd/drbd_nl.c: Use get_random

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Message-Id: <202003281643.02SGhNSB019516@sdf.org>
Date:   Wed, 21 Aug 2019 21:30:45 -0400
From:   George Spelvin <lkml@....org>
To:     linux-kernel@...r.kernel.org, lkml@....org
Cc:     Lars Ellenberg <lars.ellenberg@...bit.com>,
        Philipp Reisner <philipp.reisner@...bit.com>,
        drbd-dev@...n.linbit.com
Subject: [RFC PATCH v1 41/50] drivers/block/drbd/drbd_nl.c: Use
 get_random_u64()

There's no need to get_random_bytes() into a temporary buffer.

This is not a no-brainer change; get_random_u64() has slightly
weaker security guarantees, but they're fine for applications
like these where the random value is stored in the kernel for
as long as it's valuable.

Signed-off-by: George Spelvin <lkml@....org>
Cc: Lars Ellenberg <lars.ellenberg@...bit.com>
Cc: Philipp Reisner <philipp.reisner@...bit.com>
Cc: drbd-dev@...ts.linbit.com
---
 drivers/block/drbd/drbd_nl.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index de2f94d0103a6..ca8c706d47f3a 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -3223,9 +3223,7 @@ int drbd_adm_resume_io(struct sk_buff *skb, struct genl_info *info)
 			 * the refuse to re-connect or re-attach (because no
 			 * matching real data uuid exists).
 			 */
-			u64 val;
-			get_random_bytes(&val, sizeof(u64));
-			drbd_set_ed_uuid(device, val);
+			drbd_set_ed_uuid(device, get_random_u64());
 			drbd_warn(device, "Resumed without access to data; please tear down before attempting to re-configure.\n");
 		}
 		clear_bit(NEW_CUR_UUID, &device->flags);
-- 
2.26.0