diff options
Diffstat (limited to 'blockjob.c')
| -rw-r--r-- | blockjob.c | 84 |
1 files changed, 67 insertions, 17 deletions
diff --git a/blockjob.c b/blockjob.c index ff9a614531..0ed50b953b 100644 --- a/blockjob.c +++ b/blockjob.c @@ -37,6 +37,26 @@ #include "qemu/timer.h" #include "qapi-event.h" +/* Right now, this mutex is only needed to synchronize accesses to job->busy + * and job->sleep_timer, such as concurrent calls to block_job_do_yield and + * block_job_enter. */ +static QemuMutex block_job_mutex; + +static void block_job_lock(void) +{ + qemu_mutex_lock(&block_job_mutex); +} + +static void block_job_unlock(void) +{ + qemu_mutex_unlock(&block_job_mutex); +} + +static void __attribute__((__constructor__)) block_job_init(void) +{ + qemu_mutex_init(&block_job_mutex); +} + static void block_job_event_cancelled(BlockJob *job); static void block_job_event_completed(BlockJob *job, const char *msg); @@ -152,6 +172,7 @@ void block_job_unref(BlockJob *job) { if (--job->refcnt == 0) { BlockDriverState *bs = blk_bs(job->blk); + QLIST_REMOVE(job, job_list); bs->job = NULL; block_job_remove_all_bdrv(job); blk_remove_aio_context_notifier(job->blk, @@ -160,7 +181,7 @@ void block_job_unref(BlockJob *job) blk_unref(job->blk); error_free(job->blocker); g_free(job->id); - QLIST_REMOVE(job, job_list); + assert(!timer_pending(&job->sleep_timer)); g_free(job); } } @@ -287,6 +308,13 @@ static void coroutine_fn block_job_co_entry(void *opaque) job->driver->start(job); } +static void block_job_sleep_timer_cb(void *opaque) +{ + BlockJob *job = opaque; + + block_job_enter(job); +} + void block_job_start(BlockJob *job) { assert(job && !block_job_started(job) && job->paused && @@ -556,7 +584,7 @@ BlockJobInfo *block_job_query(BlockJob *job, Error **errp) info->type = g_strdup(BlockJobType_str(job->driver->job_type)); info->device = g_strdup(job->id); info->len = job->len; - info->busy = job->busy; + info->busy = atomic_read(&job->busy); info->paused = job->pause_count > 0; info->offset = job->offset; info->speed = job->speed; @@ -664,6 +692,9 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver, job->paused = true; job->pause_count = 1; job->refcnt = 1; + aio_timer_init(qemu_get_aio_context(), &job->sleep_timer, + QEMU_CLOCK_REALTIME, SCALE_NS, + block_job_sleep_timer_cb, job); error_setg(&job->blocker, "block device is in use by block job: %s", BlockJobType_str(driver->job_type)); @@ -729,6 +760,26 @@ static bool block_job_should_pause(BlockJob *job) return job->pause_count > 0; } +/* Yield, and schedule a timer to reenter the coroutine after @ns nanoseconds. + * Reentering the job coroutine with block_job_enter() before the timer has + * expired is allowed and cancels the timer. + * + * If @ns is (uint64_t) -1, no timer is scheduled and block_job_enter() must be + * called explicitly. */ +static void block_job_do_yield(BlockJob *job, uint64_t ns) +{ + block_job_lock(); + if (ns != -1) { + timer_mod(&job->sleep_timer, ns); + } + job->busy = false; + block_job_unlock(); + qemu_coroutine_yield(); + + /* Set by block_job_enter before re-entering the coroutine. */ + assert(job->busy); +} + void coroutine_fn block_job_pause_point(BlockJob *job) { assert(job && block_job_started(job)); @@ -746,9 +797,7 @@ void coroutine_fn block_job_pause_point(BlockJob *job) if (block_job_should_pause(job) && !block_job_is_cancelled(job)) { job->paused = true; - job->busy = false; - qemu_coroutine_yield(); /* wait for block_job_resume() */ - job->busy = true; + block_job_do_yield(job, -1); job->paused = false; } @@ -778,9 +827,17 @@ void block_job_enter(BlockJob *job) return; } - if (!job->busy) { - bdrv_coroutine_enter(blk_bs(job->blk), job->co); + block_job_lock(); + if (job->busy) { + block_job_unlock(); + return; } + + assert(!job->deferred_to_main_loop); + timer_del(&job->sleep_timer); + job->busy = true; + block_job_unlock(); + aio_co_wake(job->co); } bool block_job_is_cancelled(BlockJob *job) @@ -788,7 +845,7 @@ bool block_job_is_cancelled(BlockJob *job) return job->cancelled; } -void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns) +void block_job_sleep_ns(BlockJob *job, int64_t ns) { assert(job->busy); @@ -797,13 +854,8 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns) return; } - /* We need to leave job->busy set here, because when we have - * put a coroutine to 'sleep', we have scheduled it to run in - * the future. We cannot enter that same coroutine again before - * it wakes and runs, otherwise we risk double-entry or entry after - * completion. */ if (!block_job_should_pause(job)) { - co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns); + block_job_do_yield(job, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + ns); } block_job_pause_point(job); @@ -818,11 +870,9 @@ void block_job_yield(BlockJob *job) return; } - job->busy = false; if (!block_job_should_pause(job)) { - qemu_coroutine_yield(); + block_job_do_yield(job, -1); } - job->busy = true; block_job_pause_point(job); } |