[PATCH v2 5/6] ipc: shm: Make shmid_kernel timestamps y2038 safe

[Deepa Dinamani]

time_t is not y2038 safe. Replace all uses of
time_t by y2038 safe time64_t.

Similarly, replace the calls to get_seconds() with
y2038 safe ktime_get_real_seconds().
Note that this preserves fast access on 64 bit systems,
but 32 bit systems need sequence counters.

The syscall interfaces themselves are not changed as part of
the patch. They will be part of a different series.

Signed-off-by: Deepa Dinamani <deepa.kernel@xxxxxxxxx>
---
 include/linux/shm.h |  6 +++---
 ipc/shm.c           | 16 ++++++++--------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/linux/shm.h b/include/linux/shm.h
index 04e881829625..7bb897b25309 100644
--- a/include/linux/shm.h
+++ b/include/linux/shm.h
@@ -12,9 +12,9 @@ struct shmid_kernel /* private to the kernel */
 	struct file		*shm_file;
 	unsigned long		shm_nattch;
 	unsigned long		shm_segsz;
-	time_t			shm_atim;
-	time_t			shm_dtim;
-	time_t			shm_ctim;
+	time64_t		shm_atim;
+	time64_t		shm_dtim;
+	time64_t		shm_ctim;
 	pid_t			shm_cprid;
 	pid_t			shm_lprid;
 	struct user_struct	*mlock_user;
diff --git a/ipc/shm.c b/ipc/shm.c
index c547388487c1..f4ed20199eb4 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -199,7 +199,7 @@ static int __shm_open(struct vm_area_struct *vma)
 	if (IS_ERR(shp))
 		return PTR_ERR(shp);
 
-	shp->shm_atim = get_seconds();
+	shp->shm_atim = ktime_get_real_seconds();
 	shp->shm_lprid = task_tgid_vnr(current);
 	shp->shm_nattch++;
 	shm_unlock(shp);
@@ -286,7 +286,7 @@ static void shm_close(struct vm_area_struct *vma)
 		goto done; /* no-op */
 
 	shp->shm_lprid = task_tgid_vnr(current);
-	shp->shm_dtim = get_seconds();
+	shp->shm_dtim = ktime_get_real_seconds();
 	shp->shm_nattch--;
 	if (shm_may_destroy(ns, shp))
 		shm_destroy(ns, shp);
@@ -592,7 +592,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 	shp->shm_cprid = task_tgid_vnr(current);
 	shp->shm_lprid = 0;
 	shp->shm_atim = shp->shm_dtim = 0;
-	shp->shm_ctim = get_seconds();
+	shp->shm_ctim = ktime_get_real_seconds();
 	shp->shm_segsz = size;
 	shp->shm_nattch = 0;
 	shp->shm_file = file;
@@ -848,7 +848,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 		err = ipc_update_perm(&shmid64->shm_perm, ipcp);
 		if (err)
 			goto out_unlock0;
-		shp->shm_ctim = get_seconds();
+		shp->shm_ctim = ktime_get_real_seconds();
 		break;
 	default:
 		err = -EINVAL;
@@ -1588,7 +1588,7 @@ static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
 
 	seq_printf(s,
 		   "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
-		   "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
+		   "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
 		   SIZE_SPEC " " SIZE_SPEC "\n",
 		   shp->shm_perm.key,
 		   shp->shm_perm.id,
@@ -1601,9 +1601,9 @@ static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
 		   from_kgid_munged(user_ns, shp->shm_perm.gid),
 		   from_kuid_munged(user_ns, shp->shm_perm.cuid),
 		   from_kgid_munged(user_ns, shp->shm_perm.cgid),
-		   shp->shm_atim,
-		   shp->shm_dtim,
-		   shp->shm_ctim,
+		   (unsigned long long) shp->shm_atim,
+		   (unsigned long long) shp->shm_dtim,
+		   (unsigned long long) shp->shm_ctim,
 		   rss * PAGE_SIZE,
 		   swp * PAGE_SIZE);
 
-- 
2.11.0