Changeset 111b9b9 in mainline for kernel/generic/src/synch/condvar.c

Timestamp:

2023-02-11T19:13:44Z (2 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

master, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

4777e02

Parents:

76e17d7c

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2022-08-15 17:46:39)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2023-02-11 19:13:44)

Message:

Reimplement waitq using thread_wait/wakeup

This adds a few functions to the thread API which can be
summarized as "stop running until woken up by others".
The ordering and context-switching concerns are thus yeeted
to this abstraction and waitq only deals with maintaining
the queues. Overall, this makes the control flow in waitq
much easier to navigate.

File:

• kernel/generic/src/synch/condvar.c (modified) (5 diffs)

kernel/generic/src/synch/condvar.c

@@ -58 +58 @@
 void condvar_signal(condvar_t *cv)
 {
-        waitq_wakeup(&cv->wq, WAKEUP_FIRST);
+        waitq_signal(&cv->wq);
 }
 
@@ -68 +68 @@
 void condvar_broadcast(condvar_t *cv)
 {
-        waitq_wakeup(&cv->wq, WAKEUP_ALL);
+        waitq_wake_all(&cv->wq);
 }
 
@@ -81 +81 @@
 errno_t condvar_wait_timeout(condvar_t *cv, mutex_t *mtx, uint32_t usec)
 {
-        errno_t rc;
-        ipl_t ipl;
-        bool blocked;
+        wait_guard_t guard = waitq_sleep_prepare(&cv->wq);
 
-        ipl = waitq_sleep_prepare(&cv->wq);
         /* Unlock only after the waitq is locked so we don't miss a wakeup. */
         mutex_unlock(mtx);
 
-        cv->wq.missed_wakeups = 0;      /* Enforce blocking. */
-        rc = waitq_sleep_timeout_unsafe(&cv->wq, usec, SYNCH_FLAGS_NON_BLOCKING, &blocked);
-        assert(blocked || rc != EOK);
+        errno_t rc = waitq_sleep_timeout_unsafe(&cv->wq, usec, SYNCH_FLAGS_NON_BLOCKING, guard);
 
-        waitq_sleep_finish(&cv->wq, blocked, ipl);
-        /* Lock only after releasing the waitq to avoid a possible deadlock. */
         mutex_lock(mtx);
-
         return rc;
 }
@@ -102 +94 @@
 errno_t condvar_wait(condvar_t *cv, mutex_t *mtx)
 {
-        errno_t rc;
-        ipl_t ipl;
-        bool blocked;
+        wait_guard_t guard = waitq_sleep_prepare(&cv->wq);
 
-        ipl = waitq_sleep_prepare(&cv->wq);
         /* Unlock only after the waitq is locked so we don't miss a wakeup. */
         mutex_unlock(mtx);
 
-        cv->wq.missed_wakeups = 0;      /* Enforce blocking. */
-        rc = waitq_sleep_unsafe(&cv->wq, &blocked);
-        assert(blocked || rc != EOK);
+        errno_t rc = waitq_sleep_unsafe(&cv->wq, guard);
 
-        waitq_sleep_finish(&cv->wq, blocked, ipl);
-        /* Lock only after releasing the waitq to avoid a possible deadlock. */
         mutex_lock(mtx);
-
         return rc;
 }
@@ -142 +126 @@
     uint32_t usec, int flags)
 {
-        errno_t rc;
-        ipl_t ipl;
-        bool blocked;
-
-        ipl = waitq_sleep_prepare(&cv->wq);
+        wait_guard_t guard = waitq_sleep_prepare(&cv->wq);
 
         /* Unlock only after the waitq is locked so we don't miss a wakeup. */
         spinlock_unlock(lock);
 
-        cv->wq.missed_wakeups = 0;      /* Enforce blocking. */
-        rc = waitq_sleep_timeout_unsafe(&cv->wq, usec, flags, &blocked);
-        assert(blocked || rc != EOK);
+        errno_t rc = waitq_sleep_timeout_unsafe(&cv->wq, usec, flags, guard);
 
-        waitq_sleep_finish(&cv->wq, blocked, ipl);
-        /* Lock only after releasing the waitq to avoid a possible deadlock. */
         spinlock_lock(lock);
-
         return rc;
 }