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authorLuke T. Shumaker <lukeshu@lukeshu.com>2025-02-21 00:53:45 -0700
committerLuke T. Shumaker <lukeshu@lukeshu.com>2025-02-21 10:33:20 -0700
commitb5e84c26699d9b2beadf2e44adbd92c2c18b5bfa (patch)
treeb78617e485d06ac5e6fb4cdd7663d81c82f1ba2b /libcr_ipc
parent6639031e15b23d342efb87cc00fa51233d66b392 (diff)
libcr_ipc: Fixes and tests for sema.h
Diffstat (limited to 'libcr_ipc')
-rw-r--r--libcr_ipc/CMakeLists.txt2
-rw-r--r--libcr_ipc/include/libcr_ipc/sema.h33
-rw-r--r--libcr_ipc/tests/test_sema.c74
3 files changed, 96 insertions, 13 deletions
diff --git a/libcr_ipc/CMakeLists.txt b/libcr_ipc/CMakeLists.txt
index 05e6fa3..a7d6021 100644
--- a/libcr_ipc/CMakeLists.txt
+++ b/libcr_ipc/CMakeLists.txt
@@ -15,7 +15,7 @@ set(ipc_tests
#mutex
#owned_mutex
rpc
- #sema
+ sema
)
if (ENABLE_TESTS)
foreach(test IN LISTS ipc_tests)
diff --git a/libcr_ipc/include/libcr_ipc/sema.h b/libcr_ipc/include/libcr_ipc/sema.h
index 1064182..6db4015 100644
--- a/libcr_ipc/include/libcr_ipc/sema.h
+++ b/libcr_ipc/include/libcr_ipc/sema.h
@@ -1,12 +1,14 @@
/* libcr_ipc/sema.h - Simple semaphores for libcr
*
- * Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com>
+ * Copyright (C) 2024-2025 Luke T. Shumaker <lukeshu@lukeshu.com>
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#ifndef _LIBCR_IPC_SEMA_H_
#define _LIBCR_IPC_SEMA_H_
+#include <stdbool.h>
+
#include <libcr/coroutine.h> /* for cid_t, cr_* */
#include <libcr_ipc/_linkedlist.h>
@@ -23,6 +25,7 @@ struct _cr_sema_waiter {
*/
typedef struct {
unsigned int cnt;
+ bool unpausing;
_cr_ipc_sll_root waiters;
} cr_sema_t;
@@ -39,10 +42,10 @@ static inline void cr_sema_signal(cr_sema_t *sema) {
bool saved = cr_save_and_disable_interrupts();
sema->cnt++;
- if (sema->waiters.front) {
+ if (sema->waiters.front && !sema->unpausing) {
cr_unpause(
_cr_ipc_sll_node_cast(struct _cr_sema_waiter, sema->waiters.front)->cid);
- _cr_ipc_sll_pop_from_front(&sema->waiters);
+ sema->unpausing = true;
}
cr_restore_interrupts(saved);
}
@@ -57,10 +60,10 @@ static inline void cr_sema_signal_from_intrhandler(cr_sema_t *sema) {
cr_assert_in_intrhandler();
sema->cnt++;
- if (sema->waiters.front) {
+ if (sema->waiters.front && !sema->unpausing) {
cr_unpause_from_intrhandler(
_cr_ipc_sll_node_cast(struct _cr_sema_waiter, sema->waiters.front)->cid);
- _cr_ipc_sll_pop_from_front(&sema->waiters);
+ sema->unpausing = true;
}
}
@@ -76,15 +79,21 @@ static inline void cr_sema_wait(cr_sema_t *sema) {
cr_assert_in_coroutine();
bool saved = cr_save_and_disable_interrupts();
- if (!sema->cnt) {
- struct _cr_sema_waiter self = {
- .cid = cr_getcid(),
- };
- _cr_ipc_sll_push_to_rear(&sema->waiters, &self);
+
+ struct _cr_sema_waiter self = {
+ .cid = cr_getcid(),
+ };
+ _cr_ipc_sll_push_to_rear(&sema->waiters, &self);
+ if (sema->waiters.front != &self || !sema->cnt)
cr_pause_and_yield();
- }
- assert(sema->cnt);
+ assert(sema->waiters.front == &self && sema->cnt);
+ _cr_ipc_sll_pop_from_front(&sema->waiters);
sema->cnt--;
+ if (sema->cnt && sema->waiters.front)
+ cr_unpause(
+ _cr_ipc_sll_node_cast(struct _cr_sema_waiter, sema->waiters.front)->cid);
+ else
+ sema->unpausing = false;
cr_restore_interrupts(saved);
}
diff --git a/libcr_ipc/tests/test_sema.c b/libcr_ipc/tests/test_sema.c
new file mode 100644
index 0000000..3208237
--- /dev/null
+++ b/libcr_ipc/tests/test_sema.c
@@ -0,0 +1,74 @@
+/* libcr_ipc/tests/test_sema.c - Tests for <libcr_ipc/sema.h>
+ *
+ * Copyright (C) 2025 Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#include <libcr/coroutine.h>
+#include <libcr_ipc/sema.h>
+
+#include "test.h"
+
+int counter = 0;
+
+COROUTINE cr_first(void *_sema) {
+ cr_sema_t *sema = _sema;
+ cr_begin();
+
+ cr_sema_wait(sema);
+ counter++;
+ cr_sema_signal(sema);
+
+ cr_exit();
+}
+
+COROUTINE cr_second(void *_sema) {
+ cr_sema_t *sema = _sema;
+ cr_begin();
+
+ cr_sema_signal(sema); /* should be claimed by cr_first, which has been waiting */
+ cr_sema_wait(sema); /* should block, because cr_first claimed it */
+ test_assert(counter == 1);
+
+ cr_exit();
+}
+
+COROUTINE cr_producer(void *_sema) {
+ cr_sema_t *sema = _sema;
+ cr_begin();
+
+ for (int i = 0; i < 10; i++)
+ cr_sema_signal(sema);
+
+ cr_end();
+}
+
+COROUTINE cr_consumer(void *_sema) {
+ cr_sema_t *sema = _sema;
+ cr_begin();
+
+ for (int i = 0; i < 5; i++)
+ cr_sema_wait(sema);
+
+ cr_end();
+}
+
+int main() {
+ cr_sema_t sema = {0};
+
+ printf("== test 1 =========================================\n");
+ coroutine_add("first", cr_first, &sema);
+ coroutine_add("second", cr_second, &sema);
+ coroutine_main();
+ test_assert(sema.cnt == 0);
+
+ printf("== test 2 =========================================\n");
+ coroutine_add("consumer", cr_consumer, &sema);
+ coroutine_add("producer", cr_producer, &sema);
+ coroutine_main();
+ coroutine_add("consumer", cr_consumer, &sema);
+ coroutine_main();
+ test_assert(sema.cnt == 0);
+
+ return 0;
+}