[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PULL 05/10] co-shared-resource: protect with a mutex
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[PULL 05/10] co-shared-resource: protect with a mutex |
Date: |
Fri, 25 Jun 2021 16:00:01 +0300 |
From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
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>
---
include/qemu/co-shared-resource.h | 4 +---
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 4e4503004c..78ca5850f8 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 1c83cd9d29..a66cc07e75 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);
--
2.29.2
- [PULL 00/10] Block Jobs patches, Vladimir Sementsov-Ogievskiy, 2021/06/25
- [PULL 01/10] ratelimit: treat zero speed as unlimited, Vladimir Sementsov-Ogievskiy, 2021/06/25
- [PULL 07/10] block-copy: streamline choice of copy_range vs. read/write, Vladimir Sementsov-Ogievskiy, 2021/06/25
- [PULL 03/10] blockjob: let ratelimit handle a speed of 0, Vladimir Sementsov-Ogievskiy, 2021/06/25
- [PULL 08/10] block-copy: move progress_set_remaining in block_copy_task_end, Vladimir Sementsov-Ogievskiy, 2021/06/25
- [PULL 05/10] co-shared-resource: protect with a mutex,
Vladimir Sementsov-Ogievskiy <=
- [PULL 04/10] progressmeter: protect with a mutex, Vladimir Sementsov-Ogievskiy, 2021/06/25
- [PULL 06/10] block-copy: small refactor in block_copy_task_entry and block_copy_common, Vladimir Sementsov-Ogievskiy, 2021/06/25
- [PULL 10/10] block-copy: atomic .cancelled and .finished fields in BlockCopyCallState, Vladimir Sementsov-Ogievskiy, 2021/06/25
- [PULL 02/10] block-copy: let ratelimit handle a speed of 0, Vladimir Sementsov-Ogievskiy, 2021/06/25
- [PULL 09/10] block-copy: add CoMutex lock, Vladimir Sementsov-Ogievskiy, 2021/06/25
- Re: [PULL 00/10] Block Jobs patches, Peter Maydell, 2021/06/28
- Re: [PULL 00/10] Block Jobs patches, Peter Maydell, 2021/06/28