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author | Emanuele Giuseppe Esposito <eesposit@redhat.com> | 2021-06-14 10:11:30 +0200 |
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committer | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2021-06-25 14:24:24 +0300 |
commit | 55fa54a789f6e66fe9e7997429667e3e8917ffb9 (patch) | |
tree | 6d9d0e779bb5b5f885ea0ddfc0028049866d1a8a /util | |
parent | a7b4f8fc09ec62d09a11cce72a886c453636c547 (diff) | |
download | qemu-55fa54a789f6e66fe9e7997429667e3e8917ffb9.zip qemu-55fa54a789f6e66fe9e7997429667e3e8917ffb9.tar.gz qemu-55fa54a789f6e66fe9e7997429667e3e8917ffb9.tar.bz2 |
co-shared-resource: protect with a mutex
co-shared-resource is currently not thread-safe, as also reported
in co-shared-resource.h. Add a QemuMutex because co_try_get_from_shres
can also be invoked from non-coroutine context.
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210614081130.22134-6-eesposit@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Diffstat (limited to 'util')
-rw-r--r-- | util/qemu-co-shared-resource.c | 24 |
1 files changed, 19 insertions, 5 deletions
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); |