Changeset d742db21 in mainline

Timestamp:

2018-08-01T18:15:53Z (6 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

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

Children:

6340b4d2

Parents:

6bb136b2

git-author:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-07-30 21:07:49)

git-committer:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-08-01 18:15:53)

Message:

Implement down_timeout() and close() operations for fibril semaphore.

Location:

uspace/lib/c

Files:

• generic/fibril_synch.c (modified) (4 diffs)
• include/fibril_synch.h (modified) (2 diffs)

uspace/lib/c/generic/fibril_synch.c

@@ -664 +664 @@
          */
         assert(count >= 0);
+        sem->closed = false;
         sem->count = count;
         list_initialize(&sem->waiters);
@@ -679 +680 @@
 {
         futex_lock(&fibril_synch_futex);
+
+        if (sem->closed) {
+                futex_unlock(&fibril_synch_futex);
+                return;
+        }
+
         sem->count++;
 
@@ -700 +707 @@
 {
         futex_lock(&fibril_synch_futex);
+
+        if (sem->closed) {
+                futex_unlock(&fibril_synch_futex);
+                return;
+        }
+
         sem->count--;
 
@@ -715 +728 @@
 }
 
+errno_t fibril_semaphore_down_timeout(fibril_semaphore_t *sem, suseconds_t timeout)
+{
+        if (timeout < 0)
+                return ETIMEOUT;
+
+        futex_lock(&fibril_synch_futex);
+        if (sem->closed) {
+                futex_unlock(&fibril_synch_futex);
+                return EOK;
+        }
+
+        sem->count--;
+
+        if (sem->count >= 0) {
+                futex_unlock(&fibril_synch_futex);
+                return EOK;
+        }
+
+        awaiter_t wdata = AWAITER_INIT;
+        list_append(&wdata.link, &sem->waiters);
+
+        futex_unlock(&fibril_synch_futex);
+
+        struct timeval tv;
+        struct timeval *expires = NULL;
+        if (timeout) {
+                getuptime(&tv);
+                tv_add_diff(&tv, timeout);
+                expires = &tv;
+        }
+
+        errno_t rc = fibril_wait_timeout(&wdata.event, expires);
+        if (rc == EOK)
+                return EOK;
+
+        futex_lock(&fibril_synch_futex);
+        if (!link_in_use(&wdata.link)) {
+                futex_unlock(&fibril_synch_futex);
+                return EOK;
+        }
+
+        list_remove(&wdata.link);
+        sem->count++;
+        futex_unlock(&fibril_synch_futex);
+
+        return rc;
+}
+
+/**
+ * Close the semaphore.
+ * All future down() operations return instantly.
+ */
+void fibril_semaphore_close(fibril_semaphore_t *sem)
+{
+        futex_lock(&fibril_synch_futex);
+        sem->closed = true;
+        awaiter_t *w;
+
+        while ((w = list_pop(&sem->waiters, awaiter_t, link)))
+                fibril_notify(&w->event);
+
+        futex_unlock(&fibril_synch_futex);
+}
+
 /** @}
  */

uspace/lib/c/include/fibril_synch.h

@@ -186 +186 @@
         long int count;
         list_t waiters;
+        bool closed;
 } fibril_semaphore_t;
 
@@ -241 +242 @@
 extern void fibril_semaphore_up(fibril_semaphore_t *);
 extern void fibril_semaphore_down(fibril_semaphore_t *);
+extern errno_t fibril_semaphore_down_timeout(fibril_semaphore_t *, suseconds_t);
+extern void fibril_semaphore_close(fibril_semaphore_t *);
 
 #endif