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Diffstat (limited to 'job.c')
-rw-r--r--job.c111
1 files changed, 32 insertions, 79 deletions
diff --git a/job.c b/job.c
index 3e6f61c523..76c6d7f79d 100644
--- a/job.c
+++ b/job.c
@@ -44,8 +44,6 @@
*
* The second includes functions used by the job drivers and sometimes
* by the core block layer. These delegate the locking to the callee instead.
- *
- * TODO Actually make this true
*/
/*
@@ -99,20 +97,10 @@ struct JobTxn {
void job_lock(void)
{
- /* nop */
-}
-
-void job_unlock(void)
-{
- /* nop */
-}
-
-static void real_job_lock(void)
-{
qemu_mutex_lock(&job_mutex);
}
-static void real_job_unlock(void)
+void job_unlock(void)
{
qemu_mutex_unlock(&job_mutex);
}
@@ -187,7 +175,6 @@ static void job_txn_del_job_locked(Job *job)
/* Called with job_mutex held, but releases it temporarily. */
static int job_txn_apply_locked(Job *job, int fn(Job *))
{
- AioContext *inner_ctx;
Job *other_job, *next;
JobTxn *txn = job->txn;
int rc = 0;
@@ -199,23 +186,14 @@ static int job_txn_apply_locked(Job *job, int fn(Job *))
* break AIO_WAIT_WHILE from within fn.
*/
job_ref_locked(job);
- aio_context_release(job->aio_context);
QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
- inner_ctx = other_job->aio_context;
- aio_context_acquire(inner_ctx);
rc = fn(other_job);
- aio_context_release(inner_ctx);
if (rc) {
break;
}
}
- /*
- * Note that job->aio_context might have been changed by calling fn, so we
- * can't use a local variable to cache it.
- */
- aio_context_acquire(job->aio_context);
job_unref_locked(job);
return rc;
}
@@ -503,8 +481,12 @@ void job_unref_locked(Job *job)
assert(!job->txn);
if (job->driver->free) {
+ AioContext *aio_context = job->aio_context;
job_unlock();
+ /* FIXME: aiocontext lock is required because cb calls blk_unref */
+ aio_context_acquire(aio_context);
job->driver->free(job);
+ aio_context_release(aio_context);
job_lock();
}
@@ -583,21 +565,17 @@ void job_enter_cond_locked(Job *job, bool(*fn)(Job *job))
return;
}
- real_job_lock();
if (job->busy) {
- real_job_unlock();
return;
}
if (fn && !fn(job)) {
- real_job_unlock();
return;
}
assert(!job->deferred_to_main_loop);
timer_del(&job->sleep_timer);
job->busy = true;
- real_job_unlock();
job_unlock();
aio_co_wake(job->co);
job_lock();
@@ -628,13 +606,11 @@ static void coroutine_fn job_do_yield_locked(Job *job, uint64_t ns)
{
AioContext *next_aio_context;
- real_job_lock();
if (ns != -1) {
timer_mod(&job->sleep_timer, ns);
}
job->busy = false;
job_event_idle_locked(job);
- real_job_unlock();
job_unlock();
qemu_coroutine_yield();
job_lock();
@@ -920,10 +896,14 @@ static void job_clean(Job *job)
}
}
-/* Called with job_mutex held, but releases it temporarily */
+/*
+ * Called with job_mutex held, but releases it temporarily.
+ * Takes AioContext lock internally to invoke a job->driver callback.
+ */
static int job_finalize_single_locked(Job *job)
{
int job_ret;
+ AioContext *ctx = job->aio_context;
assert(job_is_completed_locked(job));
@@ -932,6 +912,7 @@ static int job_finalize_single_locked(Job *job)
job_ret = job->ret;
job_unlock();
+ aio_context_acquire(ctx);
if (!job_ret) {
job_commit(job);
@@ -940,15 +921,13 @@ static int job_finalize_single_locked(Job *job)
}
job_clean(job);
- job_lock();
-
if (job->cb) {
- job_ret = job->ret;
- job_unlock();
job->cb(job->opaque, job_ret);
- job_lock();
}
+ aio_context_release(ctx);
+ job_lock();
+
/* Emit events only if we actually started */
if (job_started_locked(job)) {
if (job_is_cancelled_locked(job)) {
@@ -963,13 +942,19 @@ static int job_finalize_single_locked(Job *job)
return 0;
}
-/* Called with job_mutex held, but releases it temporarily */
+/*
+ * Called with job_mutex held, but releases it temporarily.
+ * Takes AioContext lock internally to invoke a job->driver callback.
+ */
static void job_cancel_async_locked(Job *job, bool force)
{
+ AioContext *ctx = job->aio_context;
GLOBAL_STATE_CODE();
if (job->driver->cancel) {
job_unlock();
+ aio_context_acquire(ctx);
force = job->driver->cancel(job, force);
+ aio_context_release(ctx);
job_lock();
} else {
/* No .cancel() means the job will behave as if force-cancelled */
@@ -1002,10 +987,12 @@ static void job_cancel_async_locked(Job *job, bool force)
}
}
-/* Called with job_mutex held, but releases it temporarily. */
+/*
+ * Called with job_mutex held, but releases it temporarily.
+ * Takes AioContext lock internally to invoke a job->driver callback.
+ */
static void job_completed_txn_abort_locked(Job *job)
{
- AioContext *ctx;
JobTxn *txn = job->txn;
Job *other_job;
@@ -1018,54 +1005,31 @@ static void job_completed_txn_abort_locked(Job *job)
txn->aborting = true;
job_txn_ref_locked(txn);
- /*
- * We can only hold the single job's AioContext lock while calling
- * job_finalize_single() because the finalization callbacks can involve
- * calls of AIO_WAIT_WHILE(), which could deadlock otherwise.
- * Note that the job's AioContext may change when it is finalized.
- */
job_ref_locked(job);
- aio_context_release(job->aio_context);
/* Other jobs are effectively cancelled by us, set the status for
* them; this job, however, may or may not be cancelled, depending
* on the caller, so leave it. */
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
if (other_job != job) {
- ctx = other_job->aio_context;
- aio_context_acquire(ctx);
/*
* This is a transaction: If one job failed, no result will matter.
* Therefore, pass force=true to terminate all other jobs as quickly
* as possible.
*/
job_cancel_async_locked(other_job, true);
- aio_context_release(ctx);
}
}
while (!QLIST_EMPTY(&txn->jobs)) {
other_job = QLIST_FIRST(&txn->jobs);
- /*
- * The job's AioContext may change, so store it in @ctx so we
- * release the same context that we have acquired before.
- */
- ctx = other_job->aio_context;
- aio_context_acquire(ctx);
if (!job_is_completed_locked(other_job)) {
assert(job_cancel_requested_locked(other_job));
job_finish_sync_locked(other_job, NULL, NULL);
}
job_finalize_single_locked(other_job);
- aio_context_release(ctx);
}
- /*
- * Use job_ref()/job_unref() so we can read the AioContext here
- * even if the job went away during job_finalize_single().
- */
- aio_context_acquire(job->aio_context);
job_unref_locked(job);
-
job_txn_unref_locked(txn);
}
@@ -1073,15 +1037,20 @@ static void job_completed_txn_abort_locked(Job *job)
static int job_prepare_locked(Job *job)
{
int ret;
+ AioContext *ctx = job->aio_context;
GLOBAL_STATE_CODE();
+
if (job->ret == 0 && job->driver->prepare) {
job_unlock();
+ aio_context_acquire(ctx);
ret = job->driver->prepare(job);
+ aio_context_release(ctx);
job_lock();
job->ret = ret;
job_update_rc_locked(job);
}
+
return job->ret;
}
@@ -1186,11 +1155,8 @@ static void job_completed_locked(Job *job)
static void job_exit(void *opaque)
{
Job *job = (Job *)opaque;
- AioContext *ctx;
JOB_LOCK_GUARD();
-
job_ref_locked(job);
- aio_context_acquire(job->aio_context);
/* This is a lie, we're not quiescent, but still doing the completion
* callbacks. However, completion callbacks tend to involve operations that
@@ -1200,16 +1166,7 @@ static void job_exit(void *opaque)
job_event_idle_locked(job);
job_completed_locked(job);
-
- /*
- * Note that calling job_completed can move the job to a different
- * aio_context, so we cannot cache from above. job_txn_apply takes care of
- * acquiring the new lock, and we ref/unref to avoid job_completed freeing
- * the job underneath us.
- */
- ctx = job->aio_context;
job_unref_locked(job);
- aio_context_release(ctx);
}
/**
@@ -1337,14 +1294,10 @@ int job_cancel_sync(Job *job, bool force)
void job_cancel_sync_all(void)
{
Job *job;
- AioContext *aio_context;
JOB_LOCK_GUARD();
while ((job = job_next_locked(NULL))) {
- aio_context = job->aio_context;
- aio_context_acquire(aio_context);
job_cancel_sync_locked(job, true);
- aio_context_release(aio_context);
}
}
@@ -1404,8 +1357,8 @@ int job_finish_sync_locked(Job *job,
}
job_unlock();
- AIO_WAIT_WHILE(job->aio_context,
- (job_enter(job), !job_is_completed(job)));
+ AIO_WAIT_WHILE_UNLOCKED(job->aio_context,
+ (job_enter(job), !job_is_completed(job)));
job_lock();
ret = (job_is_cancelled_locked(job) && job->ret == 0)
generated by cgit v1.2.3 (git 2.26.2) at 2025-03-02 05:55:57 +0000