2 files changed, 31 insertions, 7 deletions

diff --git a/include/linux/sem.h b/include/linux/sem.h
index 55e17f68d256..976ce3a19f1b 100644
--- a/include/linux/sem.h
+++ b/include/linux/sem.h
@@ -12,7 +12,6 @@ struct task_struct;
 struct sem_array {
         struct kern_ipc_perm    ____cacheline_aligned_in_smp
                                 sem_perm;       /* permissions .. see ipc.h */
-        time_t                  sem_otime;      /* last semop time */
         time_t                  sem_ctime;      /* last change time */
         struct sem              *sem_base;      /* ptr to first semaphore in array */
         struct list_head        pending_alter;  /* pending operations */
diff --git a/ipc/sem.c b/ipc/sem.c
index 6291257ee049..51352e1bfff9 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -99,6 +99,7 @@ struct sem {
                                         /* that alter the semaphore */
         struct list_head pending_const; /* pending single-sop operations */
                                         /* that do not alter the semaphore*/
+        time_t  sem_otime;      /* candidate for sem_otime */
 } ____cacheline_aligned_in_smp;
 
 /* One queue for each sleeping process in the system. */
@@ -911,8 +912,14 @@ static void do_smart_update(struct sem_array *sma, struct sembuf *sops, int nsop
                         }
                 }
         }
-        if (otime)
-                sma->sem_otime = get_seconds();
+        if (otime) {
+                if (sops == NULL) {
+                        sma->sem_base[0].sem_otime = get_seconds();
+                } else {
+                        sma->sem_base[sops[0].sem_num].sem_otime =
+                                                                get_seconds();
+                }
+        }
 }
 
 
@@ -1058,6 +1065,21 @@ static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in,
         }
 }
 
+static time_t get_semotime(struct sem_array *sma)
+{
+        int i;
+        time_t res;
+
+        res = sma->sem_base[0].sem_otime;
+        for (i = 1; i < sma->sem_nsems; i++) {
+                time_t to = sma->sem_base[i].sem_otime;
+
+                if (to > res)
+                        res = to;
+        }
+        return res;
+}
+
 static int semctl_nolock(struct ipc_namespace *ns, int semid,
                          int cmd, int version, void __user *p)
 {
@@ -1131,9 +1153,9 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid,
                         goto out_unlock;
 
                 kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm);
-                tbuf.sem_otime  = sma->sem_otime;
-                tbuf.sem_ctime  = sma->sem_ctime;
-                tbuf.sem_nsems  = sma->sem_nsems;
+                tbuf.sem_otime = get_semotime(sma);
+                tbuf.sem_ctime = sma->sem_ctime;
+                tbuf.sem_nsems = sma->sem_nsems;
                 rcu_read_unlock();
                 if (copy_semid_to_user(p, &tbuf, version))
                         return -EFAULT;
@@ -2025,6 +2047,9 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it)
 {
         struct user_namespace *user_ns = seq_user_ns(s);
         struct sem_array *sma = it;
+        time_t sem_otime;
+
+        sem_otime = get_semotime(sma);
 
         return seq_printf(s,
                           "%10d %10d  %4o %10u %5u %5u %5u %5u %10lu %10lu\n",
@@ -2036,7 +2061,7 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it)
                           from_kgid_munged(user_ns, sma->sem_perm.gid),
                           from_kuid_munged(user_ns, sma->sem_perm.cuid),
                           from_kgid_munged(user_ns, sma->sem_perm.cgid),
-                          sma->sem_otime,
+                          sem_otime,
                           sma->sem_ctime);
 }
 #endif