posix-cpu-timers: cleanup rlimits usage

Fetch rlimit (both hard and soft) values only once and work on them.  It
removes many accesses through sig structure and makes the code cleaner.

Mostly a preparation for writable resource limits support.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 15 deletions

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 438ff4523513..dbb16bf15c45 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -982,6 +982,7 @@ static void check_thread_timers(struct task_struct *tsk,
         int maxfire;
         struct list_head *timers = tsk->cpu_timers;
         struct signal_struct *const sig = tsk->signal;
+        unsigned long soft;
 
         maxfire = 20;
         tsk->cputime_expires.prof_exp = cputime_zero;
@@ -1030,9 +1031,9 @@ static void check_thread_timers(struct task_struct *tsk,
         /*
          * Check for the special case thread timers.
          */
-        if (sig->rlim[RLIMIT_RTTIME].rlim_cur != RLIM_INFINITY) {
+        soft = sig->rlim[RLIMIT_RTTIME].rlim_cur;
+        if (soft != RLIM_INFINITY) {
                 unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max;
-                unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur;
 
                 if (hard != RLIM_INFINITY &&
                     tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
@@ -1043,14 +1044,13 @@ static void check_thread_timers(struct task_struct *tsk,
                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
                         return;
                 }
-                if (tsk->rt.timeout > DIV_ROUND_UP(*soft, USEC_PER_SEC/HZ)) {
+                if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
                         /*
                          * At the soft limit, send a SIGXCPU every second.
                          */
-                        if (sig->rlim[RLIMIT_RTTIME].rlim_cur
-                            < sig->rlim[RLIMIT_RTTIME].rlim_max) {
-                                sig->rlim[RLIMIT_RTTIME].rlim_cur +=
-                                                                USEC_PER_SEC;
+                        if (soft < hard) {
+                                soft += USEC_PER_SEC;
+                                sig->rlim[RLIMIT_RTTIME].rlim_cur = soft;
                         }
                         printk(KERN_INFO
                                 "RT Watchdog Timeout: %s[%d]\n",
@@ -1121,6 +1121,7 @@ static void check_process_timers(struct task_struct *tsk,
         unsigned long long sum_sched_runtime, sched_expires;
         struct list_head *timers = sig->cpu_timers;
         struct task_cputime cputime;
+        unsigned long soft;
 
         /*
          * Don't sample the current process CPU clocks if there are no timers.
@@ -1193,11 +1194,12 @@ static void check_process_timers(struct task_struct *tsk,
                          SIGPROF);
         check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
                          SIGVTALRM);
-
-        if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
+        soft = sig->rlim[RLIMIT_CPU].rlim_cur;
+        if (soft != RLIM_INFINITY) {
                 unsigned long psecs = cputime_to_secs(ptime);
+                unsigned long hard = sig->rlim[RLIMIT_CPU].rlim_max;
                 cputime_t x;
-                if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) {
+                if (psecs >= hard) {
                         /*
                          * At the hard limit, we just die.
                          * No need to calculate anything else now.
@@ -1205,17 +1207,17 @@ static void check_process_timers(struct task_struct *tsk,
                         __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
                         return;
                 }
-                if (psecs >= sig->rlim[RLIMIT_CPU].rlim_cur) {
+                if (psecs >= soft) {
                         /*
                          * At the soft limit, send a SIGXCPU every second.
                          */
                         __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
-                        if (sig->rlim[RLIMIT_CPU].rlim_cur
-                            < sig->rlim[RLIMIT_CPU].rlim_max) {
-                                sig->rlim[RLIMIT_CPU].rlim_cur++;
+                        if (soft < hard) {
+                                soft++;
+                                sig->rlim[RLIMIT_CPU].rlim_cur = soft;
                         }
                 }
-                x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
+                x = secs_to_cputime(soft);
                 if (cputime_eq(prof_expires, cputime_zero) ||
                     cputime_lt(x, prof_expires)) {
                         prof_expires = x;