[RFC PATCH v2 04/14] job.h: define unlocked functions

[Emanuele Giuseppe Esposito <eesposit@redhat.com>]

All these functions assume that the lock is not held, and acquire
it internally.

These functions will be useful when job_lock is globally applied,
as they will allow callers to access the job struct fields
without worrying about the job lock.

Update also the comments in blockjob.c (and move them in job.c).

Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 include/qemu/job.h | 21 +++++++++++
 blockjob.c         | 20 -----------
 job.c              | 88 ++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 107 insertions(+), 22 deletions(-)

diff --git a/include/qemu/job.h b/include/qemu/job.h
index c7a6bcad1b..d34c55dad0 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -679,4 +679,25 @@ void job_dismiss(Job **job, Error **errp);
  */
 int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp);
 
+/** Enters the @job if it is not paused */
+void job_enter_not_paused(Job *job);
+
+/** returns @job->ret */
+bool job_has_failed(Job *job);
+
+/** Returns the @job->status */
+JobStatus job_get_status(Job *job);
+
+/** Returns the @job->pause_count */
+int job_get_pause_count(Job *job);
+
+/** Returns @job->paused */
+bool job_get_paused(Job *job);
+
+/** Returns @job->busy */
+bool job_get_busy(Job *job);
+
+/** Return true if @job not paused and not cancelled */
+bool job_not_paused_nor_cancelled(Job *job);
+
 #endif
diff --git a/blockjob.c b/blockjob.c
index 4982f6a2b5..53c1e9c406 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -36,21 +36,6 @@
 #include "qemu/main-loop.h"
 #include "qemu/timer.h"
 
-/*
- * The block job API is composed of two categories of functions.
- *
- * The first includes functions used by the monitor.  The monitor is
- * peculiar in that it accesses the block job list with block_job_get, and
- * therefore needs consistency across block_job_get and the actual operation
- * (e.g. block_job_set_speed).  The consistency is achieved with
- * aio_context_acquire/release.  These functions are declared in blockjob.h.
- *
- * The second includes functions used by the block job drivers and sometimes
- * by the core block layer.  These do not care about locking, because the
- * whole coroutine runs under the AioContext lock, and are declared in
- * blockjob_int.h.
- */
-
 static bool is_block_job(Job *job)
 {
     return job_type(job) == JOB_TYPE_BACKUP ||
@@ -433,11 +418,6 @@ static void block_job_event_ready(Notifier *n, void *opaque)
 }
 
 
-/*
- * API for block job drivers and the block layer.  These functions are
- * declared in blockjob_int.h.
- */
-
 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
                        JobTxn *txn, BlockDriverState *bs, uint64_t perm,
                        uint64_t shared_perm, int64_t speed, int flags,
diff --git a/job.c b/job.c
index e393c1222f..bd36207021 100644
--- a/job.c
+++ b/job.c
@@ -32,6 +32,23 @@
 #include "trace/trace-root.h"
 #include "qapi/qapi-events-job.h"
 
+/*
+ * The job API is composed of two categories of functions.
+ *
+ * The first includes functions used by the monitor.  The monitor is
+ * peculiar in that it accesses the block job list with job_get, and
+ * therefore needs consistency across job_get and the actual operation
+ * (e.g. job_user_cancel). To achieve this consistency, the caller
+ * calls job_lock/job_unlock itself around the whole operation.
+ * These functions are declared in job-monitor.h.
+ *
+ *
+ * The second includes functions used by the block job drivers and sometimes
+ * by the core block layer. These delegate the locking to the callee instead,
+ * and are declared in job-driver.h.
+ */
+
+
 /*
  * job_mutex protects the jobs list, but also makes the
  * struct job fields thread-safe.
@@ -230,18 +247,70 @@ const char *job_type_str(const Job *job)
     return JobType_str(job_type(job));
 }
 
-bool job_is_cancelled(Job *job)
+JobStatus job_get_status(Job *job)
+{
+    JOB_LOCK_GUARD();
+    return job->status;
+}
+
+int job_get_pause_count(Job *job)
+{
+    JOB_LOCK_GUARD();
+    return job->pause_count;
+}
+
+bool job_get_paused(Job *job)
+{
+    JOB_LOCK_GUARD();
+    return job->paused;
+}
+
+bool job_get_busy(Job *job)
+{
+    JOB_LOCK_GUARD();
+    return job->busy;
+}
+
+bool job_has_failed(Job *job)
+{
+    JOB_LOCK_GUARD();
+    return job->ret < 0;
+}
+
+/* Called with job_mutex held. */
+static bool job_is_cancelled_locked(Job *job)
 {
     /* force_cancel may be true only if cancelled is true, too */
     assert(job->cancelled || !job->force_cancel);
     return job->force_cancel;
 }
 
-bool job_cancel_requested(Job *job)
+/* Called with job_mutex *not* held. */
+bool job_is_cancelled(Job *job)
+{
+    JOB_LOCK_GUARD();
+    return job_is_cancelled_locked(job);
+}
+
+bool job_not_paused_nor_cancelled(Job *job)
+{
+    JOB_LOCK_GUARD();
+    return !job->paused && !job_is_cancelled_locked(job);
+}
+
+/* Called with job_mutex held. */
+static bool job_cancel_requested_locked(Job *job)
 {
     return job->cancelled;
 }
 
+/* Called with job_mutex *not* held. */
+bool job_cancel_requested(Job *job)
+{
+    JOB_LOCK_GUARD();
+    return job_cancel_requested_locked(job);
+}
+
 /* Called with job_mutex held. */
 bool job_is_ready_locked(Job *job)
 {
@@ -294,6 +363,13 @@ bool job_is_completed(Job *job)
     return false;
 }
 
+/* Called with job_mutex lock *not* held */
+static bool job_is_completed_unlocked(Job *job)
+{
+    JOB_LOCK_GUARD();
+    return job_is_completed(job);
+}
+
 static bool job_started(Job *job)
 {
     return job->co;
@@ -593,6 +669,14 @@ void job_pause(Job *job)
     }
 }
 
+void job_enter_not_paused(Job *job)
+{
+    JOB_LOCK_GUARD();
+    if (!job->paused) {
+        job_enter_cond(job, NULL);
+    }
+}
+
 void job_resume(Job *job)
 {
     assert(job->pause_count > 0);
-- 
2.27.0