Change the job_{lock/unlock} and macros to use job_mutex. Now that they are not nop anymore, remove the aiocontext to avoid deadlocks.
Therefore: - when possible, remove completely the aiocontext lock/unlock pair - if it is used by some other functions too, reduce the locking section as much as possible, leaving the job API outside. There is only one JobDriver callback, ->free() that assumes that the aiocontext lock is held (because it calls bdrv_unref), so for now keep that under aiocontext lock. Also remove _job_{lock/unlock}, as they are replaced by the public functions. Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com> --- include/qemu/job.h | 7 --- block/replication.c | 2 + blockdev.c | 62 ++++-------------------- job-qmp.c | 38 ++++----------- job.c | 81 ++++---------------------------- tests/unit/test-bdrv-drain.c | 4 +- tests/unit/test-block-iothread.c | 2 +- tests/unit/test-blockjob.c | 13 ++--- 8 files changed, 34 insertions(+), 175 deletions(-) diff --git a/include/qemu/job.h b/include/qemu/job.h index 58b3af47e3..d417e1b601 100644 --- a/include/qemu/job.h +++ b/include/qemu/job.h @@ -608,8 +608,6 @@ void job_user_cancel(Job *job, bool force, Error **errp); * * Returns the return value from the job if the job actually completed * during the call, or -ECANCELED if it was canceled. - * - * Callers must hold the AioContext lock of job->aio_context. */ int job_cancel_sync(Job *job, bool force); @@ -633,9 +631,6 @@ void job_cancel_sync_all(void); * function). * * Returns the return value from the job. - * - * Callers must hold the AioContext lock of job->aio_context. - * * Called between job_lock and job_unlock. */ int job_complete_sync(Job *job, Error **errp); @@ -667,8 +662,6 @@ void job_dismiss(Job **job, Error **errp); * Returns 0 if the job is successfully completed, -ECANCELED if the job was * cancelled before completing, and -errno in other error cases. * - * Callers must hold the AioContext lock of job->aio_context. - * * Called between job_lock and job_unlock. */ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp); diff --git a/block/replication.c b/block/replication.c index 0f487cc215..6a60c1af1a 100644 --- a/block/replication.c +++ b/block/replication.c @@ -728,9 +728,11 @@ static void replication_stop(ReplicationState *rs, bool failover, Error **errp) * disk, secondary disk in backup_job_completed(). */ if (s->backup_job) { + aio_context_release(aio_context); job_lock(); job_cancel_sync(&s->backup_job->job, true); job_unlock(); + aio_context_acquire(aio_context); } if (!failover) { diff --git a/blockdev.c b/blockdev.c index 0bd79757fc..dfc73ef1bf 100644 --- a/blockdev.c +++ b/blockdev.c @@ -154,12 +154,7 @@ void blockdev_mark_auto_del(BlockBackend *blk) for (job = block_job_next(NULL); job; job = block_job_next(job)) { if (block_job_has_bdrv(job, blk_bs(blk))) { - AioContext *aio_context = job->job.aio_context; - aio_context_acquire(aio_context); - job_cancel(&job->job, false); - - aio_context_release(aio_context); } } @@ -1843,16 +1838,9 @@ static void drive_backup_abort(BlkActionState *common) DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common); if (state->job) { - AioContext *aio_context; - - aio_context = bdrv_get_aio_context(state->bs); - aio_context_acquire(aio_context); - job_lock(); job_cancel_sync(&state->job->job, true); job_unlock(); - - aio_context_release(aio_context); } } @@ -1946,16 +1934,9 @@ static void blockdev_backup_abort(BlkActionState *common) BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common); if (state->job) { - AioContext *aio_context; - - aio_context = bdrv_get_aio_context(state->bs); - aio_context_acquire(aio_context); - job_lock(); job_cancel_sync(&state->job->job, true); job_unlock(); - - aio_context_release(aio_context); } } @@ -3318,15 +3299,13 @@ out: aio_context_release(aio_context); } -/* Get a block job using its ID and acquire its AioContext */ -static BlockJob *find_block_job(const char *id, AioContext **aio_context, - Error **errp) +/* Get a block job using its ID. Returns with job_lock held on success */ +static BlockJob *find_block_job(const char *id, Error **errp) { BlockJob *job; assert(id != NULL); - *aio_context = NULL; job_lock(); job = block_job_get(id); @@ -3338,31 +3317,25 @@ static BlockJob *find_block_job(const char *id, AioContext **aio_context, return NULL; } - *aio_context = blk_get_aio_context(job->blk); - aio_context_acquire(*aio_context); - return job; } void qmp_block_job_set_speed(const char *device, int64_t speed, Error **errp) { - AioContext *aio_context; - BlockJob *job = find_block_job(device, &aio_context, errp); + BlockJob *job = find_block_job(device, errp); if (!job) { return; } block_job_set_speed(job, speed, errp); - aio_context_release(aio_context); job_unlock(); } void qmp_block_job_cancel(const char *device, bool has_force, bool force, Error **errp) { - AioContext *aio_context; - BlockJob *job = find_block_job(device, &aio_context, errp); + BlockJob *job = find_block_job(device, errp); if (!job) { return; @@ -3381,14 +3354,12 @@ void qmp_block_job_cancel(const char *device, trace_qmp_block_job_cancel(job); job_user_cancel(&job->job, force, errp); out: - aio_context_release(aio_context); job_unlock(); } void qmp_block_job_pause(const char *device, Error **errp) { - AioContext *aio_context; - BlockJob *job = find_block_job(device, &aio_context, errp); + BlockJob *job = find_block_job(device, errp); if (!job) { return; @@ -3396,14 +3367,12 @@ void qmp_block_job_pause(const char *device, Error **errp) trace_qmp_block_job_pause(job); job_user_pause(&job->job, errp); - aio_context_release(aio_context); job_unlock(); } void qmp_block_job_resume(const char *device, Error **errp) { - AioContext *aio_context; - BlockJob *job = find_block_job(device, &aio_context, errp); + BlockJob *job = find_block_job(device, errp); if (!job) { return; @@ -3411,14 +3380,12 @@ void qmp_block_job_resume(const char *device, Error **errp) trace_qmp_block_job_resume(job); job_user_resume(&job->job, errp); - aio_context_release(aio_context); job_unlock(); } void qmp_block_job_complete(const char *device, Error **errp) { - AioContext *aio_context; - BlockJob *job = find_block_job(device, &aio_context, errp); + BlockJob *job = find_block_job(device, errp); if (!job) { return; @@ -3426,14 +3393,12 @@ void qmp_block_job_complete(const char *device, Error **errp) trace_qmp_block_job_complete(job); job_complete(&job->job, errp); - aio_context_release(aio_context); job_unlock(); } void qmp_block_job_finalize(const char *id, Error **errp) { - AioContext *aio_context; - BlockJob *job = find_block_job(id, &aio_context, errp); + BlockJob *job = find_block_job(id, errp); if (!job) { return; @@ -3443,21 +3408,13 @@ void qmp_block_job_finalize(const char *id, Error **errp) job_ref(&job->job); job_finalize(&job->job, errp); - /* - * Job's context might have changed via job_finalize (and job_txn_apply - * automatically acquires the new one), so make sure we release the correct - * one. - */ - aio_context = blk_get_aio_context(job->blk); job_unref(&job->job); - aio_context_release(aio_context); job_unlock(); } void qmp_block_job_dismiss(const char *id, Error **errp) { - AioContext *aio_context; - BlockJob *bjob = find_block_job(id, &aio_context, errp); + BlockJob *bjob = find_block_job(id, errp); Job *job; if (!bjob) { @@ -3467,7 +3424,6 @@ void qmp_block_job_dismiss(const char *id, Error **errp) trace_qmp_block_job_dismiss(bjob); job = &bjob->job; job_dismiss(&job, errp); - aio_context_release(aio_context); job_unlock(); } diff --git a/job-qmp.c b/job-qmp.c index 8f07c51db8..d592780953 100644 --- a/job-qmp.c +++ b/job-qmp.c @@ -29,12 +29,11 @@ #include "qapi/error.h" #include "trace/trace-root.h" -/* Get a job using its ID and acquire its AioContext */ -static Job *find_job(const char *id, AioContext **aio_context, Error **errp) +/* Get a job using its ID. Returns with job_lock held on success. */ +static Job *find_job(const char *id, Error **errp) { Job *job; - *aio_context = NULL; job_lock(); job = job_get(id); @@ -44,16 +43,12 @@ static Job *find_job(const char *id, AioContext **aio_context, Error **errp) return NULL; } - *aio_context = job->aio_context; - aio_context_acquire(*aio_context); - return job; } void qmp_job_cancel(const char *id, Error **errp) { - AioContext *aio_context; - Job *job = find_job(id, &aio_context, errp); + Job *job = find_job(id, errp); if (!job) { return; @@ -61,14 +56,12 @@ void qmp_job_cancel(const char *id, Error **errp) trace_qmp_job_cancel(job); job_user_cancel(job, true, errp); - aio_context_release(aio_context); job_unlock(); } void qmp_job_pause(const char *id, Error **errp) { - AioContext *aio_context; - Job *job = find_job(id, &aio_context, errp); + Job *job = find_job(id, errp); if (!job) { return; @@ -76,14 +69,12 @@ void qmp_job_pause(const char *id, Error **errp) trace_qmp_job_pause(job); job_user_pause(job, errp); - aio_context_release(aio_context); job_unlock(); } void qmp_job_resume(const char *id, Error **errp) { - AioContext *aio_context; - Job *job = find_job(id, &aio_context, errp); + Job *job = find_job(id, errp); if (!job) { return; @@ -91,14 +82,12 @@ void qmp_job_resume(const char *id, Error **errp) trace_qmp_job_resume(job); job_user_resume(job, errp); - aio_context_release(aio_context); job_unlock(); } void qmp_job_complete(const char *id, Error **errp) { - AioContext *aio_context; - Job *job = find_job(id, &aio_context, errp); + Job *job = find_job(id, errp); if (!job) { return; @@ -106,14 +95,12 @@ void qmp_job_complete(const char *id, Error **errp) trace_qmp_job_complete(job); job_complete(job, errp); - aio_context_release(aio_context); job_unlock(); } void qmp_job_finalize(const char *id, Error **errp) { - AioContext *aio_context; - Job *job = find_job(id, &aio_context, errp); + Job *job = find_job(id, errp); if (!job) { return; @@ -123,21 +110,13 @@ void qmp_job_finalize(const char *id, Error **errp) job_ref(job); job_finalize(job, errp); - /* - * Job's context might have changed via job_finalize (and job_txn_apply - * automatically acquires the new one), so make sure we release the correct - * one. - */ - aio_context = job->aio_context; job_unref(job); - aio_context_release(aio_context); job_unlock(); } void qmp_job_dismiss(const char *id, Error **errp) { - AioContext *aio_context; - Job *job = find_job(id, &aio_context, errp); + Job *job = find_job(id, errp); if (!job) { return; @@ -145,7 +124,6 @@ void qmp_job_dismiss(const char *id, Error **errp) trace_qmp_job_dismiss(job); job_dismiss(&job, errp); - aio_context_release(aio_context); job_unlock(); } diff --git a/job.c b/job.c index 5efbf38a72..f225e770f5 100644 --- a/job.c +++ b/job.c @@ -98,26 +98,16 @@ struct JobTxn { int refcnt; }; -#define JOB_LOCK_GUARD() /* QEMU_LOCK_GUARD(&job_mutex) */ +#define JOB_LOCK_GUARD() QEMU_LOCK_GUARD(&job_mutex) -#define WITH_JOB_LOCK_GUARD() /* WITH_QEMU_LOCK_GUARD(&job_mutex) */ +#define WITH_JOB_LOCK_GUARD() WITH_QEMU_LOCK_GUARD(&job_mutex) void job_lock(void) -{ - /* nop */ -} - -void job_unlock(void) -{ - /* nop */ -} - -static void _job_lock(void) { qemu_mutex_lock(&job_mutex); } -static void _job_unlock(void) +void job_unlock(void) { qemu_mutex_unlock(&job_mutex); } @@ -185,7 +175,6 @@ static int job_txn_apply(Job *job, int fn(Job *)) * break AIO_WAIT_WHILE from within fn. */ job_ref(job); - aio_context_release(job->aio_context); QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) { rc = fn(other_job); @@ -194,11 +183,6 @@ static int job_txn_apply(Job *job, int fn(Job *)) } } - /* - * 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(job); return rc; } @@ -494,7 +478,10 @@ void job_unref(Job *job) if (job->driver->free) { job_unlock(); + /* FIXME: aiocontext lock is required because cb calls blk_unref */ + aio_context_acquire(job->aio_context); job->driver->free(job); + aio_context_release(job->aio_context); job_lock(); } @@ -570,21 +557,17 @@ void job_enter_cond(Job *job, bool(*fn)(Job *job)) return; } - _job_lock(); if (job->busy) { - _job_unlock(); return; } if (fn && !fn(job)) { - _job_unlock(); return; } assert(!job->deferred_to_main_loop); timer_del(&job->sleep_timer); job->busy = true; - _job_unlock(); job_unlock(); aio_co_enter(job->aio_context, job->co); job_lock(); @@ -608,13 +591,11 @@ void job_enter(Job *job) */ static void coroutine_fn job_do_yield(Job *job, uint64_t ns) { - _job_lock(); if (ns != -1) { timer_mod(&job->sleep_timer, ns); } job->busy = false; job_event_idle(job); - _job_unlock(); job_unlock(); qemu_coroutine_yield(); job_lock(); @@ -962,7 +943,6 @@ static void job_cancel_async(Job *job, bool force) /* Called with job_mutex held. */ static void job_completed_txn_abort(Job *job) { - AioContext *ctx; JobTxn *txn = job->txn; Job *other_job; @@ -975,54 +955,28 @@ static void job_completed_txn_abort(Job *job) txn->aborting = true; job_txn_ref(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(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(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(other_job)) { assert(job_cancel_requested_locked(other_job)); job_finish_sync(other_job, NULL, NULL); } job_finalize_single(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(job); - job_txn_unref(txn); } @@ -1142,11 +1096,7 @@ static void job_completed(Job *job) static void job_exit(void *opaque) { Job *job = (Job *)opaque; - AioContext *ctx; - JOB_LOCK_GUARD(); - job_ref(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 @@ -1156,16 +1106,6 @@ static void job_exit(void *opaque) job_event_idle(job); job_completed(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(job); - aio_context_release(ctx); } /** @@ -1279,14 +1219,10 @@ 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(NULL))) { - aio_context = job->aio_context; - aio_context_acquire(aio_context); job_cancel_sync(job, true); - aio_context_release(aio_context); } } @@ -1331,8 +1267,9 @@ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp) } job_unlock(); - AIO_WAIT_WHILE(job->aio_context, - (job_enter(job), !job_is_completed_unlocked(job))); + AIO_WAIT_WHILE_UNLOCKED(job->aio_context, + (job_enter(job), + !job_is_completed_unlocked(job))); job_lock(); ret = (job_is_cancelled_locked(job) && job->ret == 0) ? diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c index 535c39b5a8..83485a33aa 100644 --- a/tests/unit/test-bdrv-drain.c +++ b/tests/unit/test-bdrv-drain.c @@ -928,9 +928,9 @@ static void test_blockjob_common_drain_node(enum drain_type drain_type, tjob->prepare_ret = -EIO; break; } + aio_context_release(ctx); job_start(&job->job); - aio_context_release(ctx); if (use_iothread) { /* job_co_entry() is run in the I/O thread, wait for the actual job @@ -994,12 +994,12 @@ static void test_blockjob_common_drain_node(enum drain_type drain_type, g_assert_false(job_get_paused(&job->job)); g_assert_true(job_get_busy(&job->job)); /* We're in qemu_co_sleep_ns() */ - aio_context_acquire(ctx); job_lock(); ret = job_complete_sync(&job->job, &error_abort); job_unlock(); g_assert_cmpint(ret, ==, (result == TEST_JOB_SUCCESS ? 0 : -EIO)); + aio_context_acquire(ctx); if (use_iothread) { blk_set_aio_context(blk_src, qemu_get_aio_context(), &error_abort); assert(blk_get_aio_context(blk_target) == qemu_get_aio_context()); diff --git a/tests/unit/test-block-iothread.c b/tests/unit/test-block-iothread.c index f39cb8b7ef..cf197347b7 100644 --- a/tests/unit/test-block-iothread.c +++ b/tests/unit/test-block-iothread.c @@ -455,10 +455,10 @@ static void test_attach_blockjob(void) aio_poll(qemu_get_aio_context(), false); } - aio_context_acquire(ctx); job_lock(); job_complete_sync(&tjob->common.job, &error_abort); job_unlock(); + aio_context_acquire(ctx); blk_set_aio_context(blk, qemu_get_aio_context(), &error_abort); aio_context_release(ctx); diff --git a/tests/unit/test-blockjob.c b/tests/unit/test-blockjob.c index b94e1510c9..11cff70a6b 100644 --- a/tests/unit/test-blockjob.c +++ b/tests/unit/test-blockjob.c @@ -228,10 +228,6 @@ static void cancel_common(CancelJob *s) BlockJob *job = &s->common; BlockBackend *blk = s->blk; JobStatus sts = job->job.status; - AioContext *ctx; - - ctx = job->job.aio_context; - aio_context_acquire(ctx); job_lock(); job_cancel_sync(&job->job, true); @@ -244,7 +240,6 @@ static void cancel_common(CancelJob *s) job_unlock(); destroy_blk(blk); - aio_context_release(ctx); } static void test_cancel_created(void) @@ -381,11 +376,9 @@ static void test_cancel_concluded(void) aio_poll(qemu_get_aio_context(), true); assert(job_get_status(job) == JOB_STATUS_PENDING); - aio_context_acquire(job->aio_context); job_lock(); job_finalize(job, &error_abort); job_unlock(); - aio_context_release(job->aio_context); assert(job_get_status(job) == JOB_STATUS_CONCLUDED); cancel_common(s); @@ -478,9 +471,7 @@ static void test_complete_in_standby(void) /* Wait for the job to become READY */ job_start(job); - aio_context_acquire(ctx); - AIO_WAIT_WHILE(ctx, job_get_status(job) != JOB_STATUS_READY); - aio_context_release(ctx); + AIO_WAIT_WHILE_UNLOCKED(ctx, job_get_status(job) != JOB_STATUS_READY); /* Begin the drained section, pausing the job */ bdrv_drain_all_begin(); @@ -498,6 +489,7 @@ static void test_complete_in_standby(void) job_complete(job, &error_abort); /* The test is done now, clean up. */ + aio_context_release(ctx); job_finish_sync(job, NULL, &error_abort); assert(job->status == JOB_STATUS_PENDING); @@ -507,6 +499,7 @@ static void test_complete_in_standby(void) job_dismiss(&job, &error_abort); job_unlock(); + aio_context_acquire(ctx); destroy_blk(blk); aio_context_release(ctx); iothread_join(iothread); -- 2.27.0