diff options
| -rw-r--r-- | blockjob.c | 63 | ||||
| -rw-r--r-- | include/block/blockjob.h | 8 | ||||
| -rw-r--r-- | include/block/blockjob_int.h | 4 |
3 files changed, 61 insertions, 14 deletions
diff --git a/blockjob.c b/blockjob.c index 4d22b7d2fb..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); @@ -161,6 +181,7 @@ void block_job_unref(BlockJob *job) blk_unref(job->blk); error_free(job->blocker); g_free(job->id); + 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)); @@ -729,9 +760,20 @@ static bool block_job_should_pause(BlockJob *job) return job->pause_count > 0; } -static void block_job_do_yield(BlockJob *job) +/* 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. */ @@ -755,7 +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; - block_job_do_yield(job); + block_job_do_yield(job, -1); job->paused = false; } @@ -785,11 +827,16 @@ void block_job_enter(BlockJob *job) return; } + 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); } @@ -807,14 +854,8 @@ void block_job_sleep_ns(BlockJob *job, 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), - QEMU_CLOCK_REALTIME, ns); + block_job_do_yield(job, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + ns); } block_job_pause_point(job); @@ -830,7 +871,7 @@ void block_job_yield(BlockJob *job) } if (!block_job_should_pause(job)) { - block_job_do_yield(job); + block_job_do_yield(job, -1); } block_job_pause_point(job); diff --git a/include/block/blockjob.h b/include/block/blockjob.h index 67c0968fa5..00403d9482 100644 --- a/include/block/blockjob.h +++ b/include/block/blockjob.h @@ -77,7 +77,7 @@ typedef struct BlockJob { /** * Set to false by the job while the coroutine has yielded and may be * re-entered by block_job_enter(). There may still be I/O or event loop - * activity pending. + * activity pending. Accessed under block_job_mutex (in blockjob.c). */ bool busy; @@ -135,6 +135,12 @@ typedef struct BlockJob { */ int ret; + /** + * Timer that is used by @block_job_sleep_ns. Accessed under + * block_job_mutex (in blockjob.c). + */ + QEMUTimer sleep_timer; + /** Non-NULL if this job is part of a transaction */ BlockJobTxn *txn; QLIST_ENTRY(BlockJob) txn_list; diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h index f7ab183a39..c9b23b0cc9 100644 --- a/include/block/blockjob_int.h +++ b/include/block/blockjob_int.h @@ -142,8 +142,8 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver, * @ns: How many nanoseconds to stop for. * * Put the job to sleep (assuming that it wasn't canceled) for @ns - * %QEMU_CLOCK_REALTIME nanoseconds. Canceling the job will not interrupt - * the wait, so the cancel will not process until the coroutine wakes up. + * %QEMU_CLOCK_REALTIME nanoseconds. Canceling the job will immediately + * interrupt the wait. */ void block_job_sleep_ns(BlockJob *job, int64_t ns); |