Try to make the control flow of this function easier to analyze.
Signed-off-by: Matt Helsley <[email protected]>
---
futex/pi.c | 61 ++++++++++++++++++++++++++++++++++++-----------------------
1 files changed, 37 insertions(+), 24 deletions(-)
diff --git a/futex/pi.c b/futex/pi.c
index 41f539b..53d4c5d 100644
--- a/futex/pi.c
+++ b/futex/pi.c
@@ -392,6 +392,34 @@ int child_static_priority(int child_num)
return prio_min + child_num; /* inverted: + (N - 1 - child_num);*/
}
+void release_pi_futex(int *retries, int *retval, pid_t tid)
+{
+ int pi_val;
+
+ do {
+ /* Release the futex */
+ pi_val = atomic_cmpxchg(pi_futex, tid, 0);
+ if (pi_val != tid) {
+ switch (do_unlock_contended_pi_futex(*retries)) {
+ case -1: /* error -- we already logged the details */
+ *retval = -100;
+ break;
+ case 0: /* ok */
+ break;
+ case 1: /* try again */
+ if (retries) {
+ retries--;
+ continue;
+ }
+ *retval = -101;
+ break;
+ }
+ } /* else we were the last to hold the futex */
+ } while(retries);
+
+ log("INFO", "exited the critical section\n");
+}
+
int kid(void *child_num_as_pointer)
{
pid_t tid = gettid();
@@ -441,7 +469,8 @@ int kid(void *child_num_as_pointer)
pi_val = atomic_cmpxchg(pi_futex, 0, tid);
if (pi_val == tid) {
log("WARN", "found uncontended pi futex.\n");
- goto release_pi_futex;
+ release_pi_futex(&retries, &retval, tid);
+ goto out;
}
retval--;
@@ -456,7 +485,8 @@ int kid(void *child_num_as_pointer)
retval--;
if (get_dynamic_priority(tid, &held_prio)) {
log("FAIL", "could not get priority.\n");
- goto release_pi_futex;
+ release_pi_futex(&retries, &retval, tid);
+ goto out;
}
retval--;
@@ -467,7 +497,8 @@ int kid(void *child_num_as_pointer)
* should wake the next highest priority waiter.
*/
log("FAIL", "Not woken in priority order.\n");
- goto release_pi_futex;
+ release_pi_futex(&retries, &retval, tid);
+ goto out;
}
log("PASS", "Woken in priority order.\n");
retval = 0;
@@ -499,7 +530,8 @@ int kid(void *child_num_as_pointer)
/* Compare our priority to what we set above. */
if (get_dynamic_priority(tid, &held_prio)) {
retries = 100;
- goto release_pi_futex;
+ release_pi_futex(&retries, &retval, tid);
+ goto out;
}
usleep(1000);
retries--;
@@ -522,26 +554,7 @@ int kid(void *child_num_as_pointer)
}
}
-release_pi_futex:
- /* Release the futex */
- pi_val = atomic_cmpxchg(pi_futex, tid, 0);
- if (pi_val != tid) {
- switch (do_unlock_contended_pi_futex(retries)) {
- case -1: /* error -- we already logged the details */
- retval = -100;
- break;
- case 0: /* ok */
- break;
- case 1: /* try again */
- if (retries) {
- retries--;
- goto release_pi_futex;
- }
- retval = -101;
- break;
- }
- } /* else we were the last to hold the futex */
- log("INFO", "exited the critical section\n");
+ release_pi_futex(&retries, &retval, tid);
out:
log("INFO", "exiting\n");
/* smp_mb() ?? */
--
1.6.3.3
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