[PATCH] AFS: Correctly use 64-bit time for UUID

From: Tina Ruchandani
Date: Fri Oct 30 2015 - 04:51:25 EST


UUID calculation uses 'struct timespec' whose seconds will overflow
in year 2038 and beyond for 32-bit systems. This patch removes the
dependency on 'struct timespec' by using ktime_get_real().
While the patch does not fix a 'bug' as such, it is part of a larger
effort to remove instances of 'struct timespec' and other data-structures
suffering from y2038 problem from the kernel.

Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Tina Ruchandani <ruchandani.tina@xxxxxxxxx>
---
Changes in v2:
- Use 64-bit division API, fix 32-bit build
---
fs/afs/main.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/afs/main.c b/fs/afs/main.c
index 35de0c0..129ff43 100644
--- a/fs/afs/main.c
+++ b/fs/afs/main.c
@@ -14,6 +14,7 @@
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/sched.h>
+#include <linux/ktime.h>
#include "internal.h"

MODULE_DESCRIPTION("AFS Client File System");
@@ -37,7 +38,6 @@ struct workqueue_struct *afs_wq;
*/
static int __init afs_get_client_UUID(void)
{
- struct timespec ts;
u64 uuidtime;
u16 clockseq;
int ret;
@@ -48,9 +48,7 @@ static int __init afs_get_client_UUID(void)
if (ret < 0)
return ret;

- getnstimeofday(&ts);
- uuidtime = (u64) ts.tv_sec * 1000 * 1000 * 10;
- uuidtime += ts.tv_nsec / 100;
+ uuidtime = ktime_divns(ktime_get_real(), 100);
uuidtime += AFS_UUID_TO_UNIX_TIME;
afs_uuid.time_low = uuidtime;
afs_uuid.time_mid = uuidtime >> 32;
--
1.9.1

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