diff options
| -rw-r--r-- | include/qemu/co-shared-resource.h | 4 | ||||
| -rw-r--r-- | util/qemu-co-shared-resource.c | 24 |
2 files changed, 20 insertions, 8 deletions
diff --git a/include/qemu/co-shared-resource.h b/include/qemu/co-shared-resource.h index 4e45030..78ca585 100644 --- a/include/qemu/co-shared-resource.h +++ b/include/qemu/co-shared-resource.h @@ -26,15 +26,13 @@ #ifndef QEMU_CO_SHARED_RESOURCE_H #define QEMU_CO_SHARED_RESOURCE_H - +/* Accesses to co-shared-resource API are thread-safe */ typedef struct SharedResource SharedResource; /* * Create SharedResource structure * * @total: total amount of some resource to be shared between clients - * - * Note: this API is not thread-safe. */ SharedResource *shres_create(uint64_t total); diff --git a/util/qemu-co-shared-resource.c b/util/qemu-co-shared-resource.c index 1c83cd9..a66cc07 100644 --- a/util/qemu-co-shared-resource.c +++ b/util/qemu-co-shared-resource.c @@ -28,10 +28,13 @@ #include "qemu/co-shared-resource.h" struct SharedResource { - uint64_t total; - uint64_t available; + uint64_t total; /* Set in shres_create() and not changed anymore */ + /* State fields protected by lock */ + uint64_t available; CoQueue queue; + + QemuMutex lock; }; SharedResource *shres_create(uint64_t total) @@ -40,6 +43,7 @@ SharedResource *shres_create(uint64_t total) s->total = s->available = total; qemu_co_queue_init(&s->queue); + qemu_mutex_init(&s->lock); return s; } @@ -47,10 +51,12 @@ SharedResource *shres_create(uint64_t total) void shres_destroy(SharedResource *s) { assert(s->available == s->total); + qemu_mutex_destroy(&s->lock); g_free(s); } -bool co_try_get_from_shres(SharedResource *s, uint64_t n) +/* Called with lock held. */ +static bool co_try_get_from_shres_locked(SharedResource *s, uint64_t n) { if (s->available >= n) { s->available -= n; @@ -60,16 +66,24 @@ bool co_try_get_from_shres(SharedResource *s, uint64_t n) return false; } +bool co_try_get_from_shres(SharedResource *s, uint64_t n) +{ + QEMU_LOCK_GUARD(&s->lock); + return co_try_get_from_shres_locked(s, n); +} + void coroutine_fn co_get_from_shres(SharedResource *s, uint64_t n) { assert(n <= s->total); - while (!co_try_get_from_shres(s, n)) { - qemu_co_queue_wait(&s->queue, NULL); + QEMU_LOCK_GUARD(&s->lock); + while (!co_try_get_from_shres_locked(s, n)) { + qemu_co_queue_wait(&s->queue, &s->lock); } } void coroutine_fn co_put_to_shres(SharedResource *s, uint64_t n) { + QEMU_LOCK_GUARD(&s->lock); assert(s->total - s->available >= n); s->available += n; qemu_co_queue_restart_all(&s->queue); |