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-rw-r--r--blockjob.c38
-rw-r--r--include/block/blockjob.h35
2 files changed, 65 insertions, 8 deletions
diff --git a/blockjob.c b/blockjob.c
index 21cc3ee332..874b573bd5 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -257,6 +257,32 @@ static bool block_job_should_pause(BlockJob *job)
return job->pause_count > 0;
}
+void coroutine_fn block_job_pause_point(BlockJob *job)
+{
+ if (!block_job_should_pause(job)) {
+ return;
+ }
+ if (block_job_is_cancelled(job)) {
+ return;
+ }
+
+ if (job->driver->pause) {
+ job->driver->pause(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;
+ job->paused = false;
+ }
+
+ if (job->driver->resume) {
+ job->driver->resume(job);
+ }
+}
+
void block_job_resume(BlockJob *job)
{
assert(job->pause_count > 0);
@@ -364,11 +390,9 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
if (!block_job_should_pause(job)) {
co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns);
}
- /* The job can be paused while sleeping, so check this again */
- if (block_job_should_pause(job)) {
- qemu_coroutine_yield();
- }
job->busy = true;
+
+ block_job_pause_point(job);
}
void block_job_yield(BlockJob *job)
@@ -381,8 +405,12 @@ void block_job_yield(BlockJob *job)
}
job->busy = false;
- qemu_coroutine_yield();
+ if (!block_job_should_pause(job)) {
+ qemu_coroutine_yield();
+ }
job->busy = true;
+
+ block_job_pause_point(job);
}
BlockJobInfo *block_job_query(BlockJob *job)
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 8fcecf9a79..7739f37c3a 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -70,6 +70,20 @@ typedef struct BlockJobDriver {
* never both.
*/
void (*abort)(BlockJob *job);
+
+ /**
+ * If the callback is not NULL, it will be invoked when the job transitions
+ * into the paused state. Paused jobs must not perform any asynchronous
+ * I/O or event loop activity. This callback is used to quiesce jobs.
+ */
+ void coroutine_fn (*pause)(BlockJob *job);
+
+ /**
+ * If the callback is not NULL, it will be invoked when the job transitions
+ * out of the paused state. Any asynchronous I/O or event loop activity
+ * should be restarted from this callback.
+ */
+ void coroutine_fn (*resume)(BlockJob *job);
} BlockJobDriver;
/**
@@ -119,13 +133,19 @@ struct BlockJob {
bool user_paused;
/**
- * Set to false by the job while it is in a quiescent state, where
- * no I/O is pending and the job has yielded on any condition
- * that is not detected by #aio_poll, such as a timer.
+ * 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.
*/
bool busy;
/**
+ * Set to true by the job while it is in a quiescent state, where
+ * no I/O or event loop activity is pending.
+ */
+ bool paused;
+
+ /**
* Set to true when the job is ready to be completed.
*/
bool ready;
@@ -299,6 +319,15 @@ bool block_job_is_cancelled(BlockJob *job);
BlockJobInfo *block_job_query(BlockJob *job);
/**
+ * block_job_pause_point:
+ * @job: The job that is ready to pause.
+ *
+ * Pause now if block_job_pause() has been called. Block jobs that perform
+ * lots of I/O must call this between requests so that the job can be paused.
+ */
+void coroutine_fn block_job_pause_point(BlockJob *job);
+
+/**
* block_job_pause:
* @job: The job to be paused.
*