Jobs in a sequential transaction should never be started with job_start
manually. job_txn_start_seq and the sequentially called job_start will
take care of it, 'assert'ing in case a job is already running or has
finished.
Signed-off-by: Stefan Reiter <s.rei...@proxmox.com>
---
include/qemu/job.h | 12 ++++++++++++
job.c | 24 ++++++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/include/qemu/job.h b/include/qemu/job.h
index 32aabb1c60..f7a6a0926a 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -280,6 +280,18 @@ typedef enum JobCreateFlags {
*/
JobTxn *job_txn_new(void);
+/**
+ * Create a new transaction and set it to sequential mode, i.e. run all jobs
+ * one after the other instead of at the same time.
+ */
+JobTxn *job_txn_new_seq(void);
+
+/**
+ * Helper method to start the first job in a sequential transaction to kick it
+ * off. Other jobs will be run after this one completes.
+ */
+void job_txn_start_seq(JobTxn *txn);
+
/**
* Release a reference that was previously acquired with job_txn_add_job or
* job_txn_new. If it's the last reference to the object, it will be freed.
diff --git a/job.c b/job.c
index 8fecf38960..4df7c1d2ca 100644
--- a/job.c
+++ b/job.c
@@ -72,6 +72,8 @@ struct JobTxn {
/* Reference count */
int refcnt;
+
+ bool sequential;
};
/* Right now, this mutex is only needed to synchronize accesses to job->busy
@@ -102,6 +104,25 @@ JobTxn *job_txn_new(void)
return txn;
}
+JobTxn *job_txn_new_seq(void)
+{
+ JobTxn *txn = job_txn_new();
+ txn->sequential = true;
+ return txn;
+}
+
+void job_txn_start_seq(JobTxn *txn)
+{
+ assert(txn->sequential);
+ assert(!txn->aborting);
+
+ Job *first = QLIST_FIRST(&txn->jobs);
+ assert(first);
+ assert(first->status == JOB_STATUS_CREATED);
+
+ job_start(first);
+}
+
static void job_txn_ref(JobTxn *txn)
{
txn->refcnt++;
@@ -840,6 +861,9 @@ static void job_completed_txn_success(Job *job)
*/
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
if (!job_is_completed(other_job)) {
+ if (txn->sequential) {
+ job_start(other_job);
+ }
return;
}
assert(other_job->ret == 0);
--
2.20.1
