[src/trunk]: src/sys/external/bsd/drm2/dist/drm drm: Timeout audit -- drm_syn...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8af51e148e73
branches:  trunk
changeset: 1028964:8af51e148e73
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Dec 19 12:35:45 2021 +0000

description:
drm: Timeout audit -- drm_syncobj.c.

diffstat:

 sys/external/bsd/drm2/dist/drm/drm_syncobj.c |  115 ++++++++++++++------------
 1 files changed, 61 insertions(+), 54 deletions(-)

diffs (175 lines):

diff -r e508e8ad852b -r 8af51e148e73 sys/external/bsd/drm2/dist/drm/drm_syncobj.c
--- a/sys/external/bsd/drm2/dist/drm/drm_syncobj.c      Sun Dec 19 12:35:37 2021 +0000
+++ b/sys/external/bsd/drm2/dist/drm/drm_syncobj.c      Sun Dec 19 12:35:45 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: drm_syncobj.c,v 1.6 2021/12/19 12:35:28 riastradh Exp $        */
+/*     $NetBSD: drm_syncobj.c,v 1.7 2021/12/19 12:35:45 riastradh Exp $        */
 
 /*
  * Copyright 2017 Red Hat
@@ -125,7 +125,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: drm_syncobj.c,v 1.6 2021/12/19 12:35:28 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: drm_syncobj.c,v 1.7 2021/12/19 12:35:45 riastradh Exp $");
 
 #include <linux/anon_inodes.h>
 #include <linux/file.h>
@@ -169,32 +169,6 @@
        u64    point;
 };
 
-#ifdef __NetBSD__
-static int
-cv_wait_timeout_sig(kcondvar_t *cv, kmutex_t *lock, long *timeoutp)
-{
-       unsigned long ticks = *timeoutp;
-       unsigned starttime, endtime;
-       int error;
-
-       starttime = hardclock_ticks;
-       error = cv_timedwait_sig(cv, lock, MIN(ticks, INT_MAX));
-       endtime = hardclock_ticks;
-
-       if (error == EINTR || error == ERESTART) {
-               return ERESTARTSYS;
-       } else {
-               KASSERTMSG(error == 0 || error == EWOULDBLOCK,
-                   "error=%d", error);
-               if (endtime - starttime < ticks)
-                       *timeoutp = ticks - (endtime - starttime);
-               else
-                       *timeoutp = 0;
-               return 0;
-       }
-}
-#endif
-
 static void syncobj_wait_syncobj_func(struct drm_syncobj *syncobj,
                                      struct syncobj_wait_entry *wait);
 
@@ -404,11 +378,45 @@
 
 #ifdef __NetBSD__
        spin_lock(&syncobj->lock);
-#endif
+       ret = 0;
+       while (wait.fence == NULL) {
+               unsigned start, end;
+
+               if (timeout == 0) {
+                       ret = -ETIME;
+                       break;
+               }
+               mutex_spin_enter(&lock);
+               spin_unlock(&syncobj->lock);
+               start = getticks();
+               /* XXX errno NetBSD->Linux */
+               ret = -cv_timedwait_sig(&cv, &lock, MIN(timeout, INT_MAX/2));
+               end = getticks();
+               timeout -= MIN(timeout, end - start);
+               mutex_spin_exit(&lock);
+               spin_lock(&syncobj->lock);
+               KASSERTMSG((ret == 0 || ret == -EINTR || ret == -ERESTART ||
+                       ret == -EWOULDBLOCK), "ret=%d", ret);
+               if (ret == -EINTR || ret == -ERESTART) {
+                       ret = -ERESTARTSYS;
+                       break;
+               } else if (ret == -EWOULDBLOCK) {
+                       /* Check once more, then give up.  */
+                       ret = 0;
+                       timeout = 0;
+               } else {
+                       KASSERT(ret == 0);
+               }
+       }
+       *fence = wait.fence;
+       if (wait.node.next)
+               list_del_init(&wait.node);
+       spin_unlock(&syncobj->lock);
+       cv_destroy(&cv);
+       mutex_destroy(&lock);
+#else
        do {
-#ifndef __NetBSD__
                set_current_state(TASK_INTERRUPTIBLE);
-#endif
                if (wait.fence) {
                        ret = 0;
                        break;
@@ -418,36 +426,20 @@
                         break;
                 }
 
-#ifdef __NetBSD__
-               mutex_enter(&lock);
-               spin_unlock(&syncobj->lock);
-               /* XXX errno NetBSD->Linux */
-               ret = -cv_wait_timeout_sig(&cv, &lock, &timeout);
-               mutex_exit(&lock);
-               spin_lock(&syncobj->lock);
-               if (ret)
-                       break;
-#else
                if (signal_pending(current)) {
                        ret = -ERESTARTSYS;
                        break;
                }
 
                 timeout = schedule_timeout(timeout);
-#endif
        } while (1);
 
-#ifdef __NetBSD__
-       spin_unlock(&syncobj->lock);
-       cv_destroy(&cv);
-       mutex_destroy(&lock);
-#else
        __set_current_state(TASK_RUNNING);
-#endif
        *fence = wait.fence;
 
        if (wait.node.next)
                drm_syncobj_remove_wait(syncobj, &wait);
+#endif
 
        return ret;
 }
@@ -1184,15 +1176,30 @@
                }
 
 #ifdef __NetBSD__
-               mutex_enter(&lock);
-               if (signalled)
+               mutex_spin_enter(&lock);
+               if (signalled) {
                        ret = 0;
-               else
-                       ret = -cv_wait_timeout_sig(&cv, &lock, &timeout);
-               mutex_exit(&lock);
-               if (ret) {
+               } else {
+                       unsigned start, end;
+
+                       start = getticks();
+                       /* XXX errno NetBSD->Linux */
+                       ret = -cv_timedwait_sig(&cv, &lock,
+                           MIN(timeout, INT_MAX/2));
+                       end = getticks();
+                       timeout -= MIN(timeout, end - start);
+               }
+               mutex_spin_exit(&lock);
+               KASSERTMSG((ret == 0 || ret == -EINTR || ret == -ERESTART ||
+                       ret == -EWOULDBLOCK), "ret=%d", ret);
+               if (ret == -EINTR || ret == -ERESTART) {
                        timeout = -ERESTARTSYS;
                        goto done_waiting;
+               } else if (ret == -EWOULDBLOCK) {
+                       /* Poll fences once more, then exit.  */
+                       timeout = 0;
+               } else {
+                       KASSERT(ret == 0);
                }
 #else
                if (signal_pending(current)) {