Merge remote-tracking branch 'remotes/xanclic/tags/pull-block-2018-08-31-v2' into staging

Block patches:
- (Block) job exit refactoring, part 1
  (removing job_defer_to_main_loop())
- test-bdrv-drain leak fix

# gpg: Signature made Fri 31 Aug 2018 15:30:33 BST
# gpg:                using RSA key F407DB0061D5CF40
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>"
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* remotes/xanclic/tags/pull-block-2018-08-31-v2:
  jobs: remove job_defer_to_main_loop
  jobs: remove ret argument to job_completed; privatize it
  block/backup: make function variables consistently named
  jobs: utilize job_exit shim
  block/mirror: utilize job_exit shim
  block/commit: utilize job_exit shim
  jobs: add exit shim
  jobs: canonize Error object
  jobs: change start callback to run callback
  tests: fix bdrv-drain leak

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 34 insertions, 36 deletions

diff --git a/include/qemu/job.h b/include/qemu/job.h
index 18c9223e31..e0cff702b7 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -124,12 +124,20 @@ typedef struct Job {
     /** Estimated progress_current value at the completion of the job */
     int64_t progress_total;
 
-    /** Error string for a failed job (NULL if, and only if, job->ret == 0) */
-    char *error;
-
-    /** ret code passed to job_completed. */
+    /**
+     * Return code from @run and/or @prepare callback(s).
+     * Not final until the job has reached the CONCLUDED status.
+     * 0 on success, -errno on failure.
+     */
     int ret;
 
+    /**
+     * Error object for a failed job.
+     * If job->ret is nonzero and an error object was not set, it will be set
+     * to strerror(-job->ret) during job_completed.
+     */
+    Error *err;
+
     /** The completion function that will be called when the job completes.  */
     BlockCompletionFunc *cb;
 
@@ -168,8 +176,17 @@ struct JobDriver {
     /** Enum describing the operation */
     JobType job_type;
 
-    /** Mandatory: Entrypoint for the Coroutine. */
-    CoroutineEntry *start;
+    /**
+     * Mandatory: Entrypoint for the Coroutine.
+     *
+     * This callback will be invoked when moving from CREATED to RUNNING.
+     *
+     * If this callback returns nonzero, the job transaction it is part of is
+     * aborted. If it returns zero, the job moves into the WAITING state. If it
+     * is the last job to complete in its transaction, all jobs in the
+     * transaction move from WAITING to PENDING.
+     */
+    int coroutine_fn (*run)(Job *job, Error **errp);
 
     /**
      * If the callback is not NULL, it will be invoked when the job transitions
@@ -205,6 +222,17 @@ struct JobDriver {
     void (*drain)(Job *job);
 
     /**
+     * If the callback is not NULL, exit will be invoked from the main thread
+     * when the job's coroutine has finished, but before transactional
+     * convergence; before @prepare or @abort.
+     *
+     * FIXME TODO: This callback is only temporary to transition remaining jobs
+     * to prepare/commit/abort/clean callbacks and will be removed before 3.1.
+     * is released.
+     */
+    void (*exit)(Job *job);
+
+    /**
      * If the callback is not NULL, prepare will be invoked when all the jobs
      * belonging to the same transaction complete; or upon this job's completion
      * if it is not in a transaction.
@@ -481,19 +509,6 @@ void job_early_fail(Job *job);
 /** Moves the @job from RUNNING to READY */
 void job_transition_to_ready(Job *job);
 
-/**
- * @job: The job being completed.
- * @ret: The status code.
- * @error: The error message for a failing job (only with @ret < 0). If @ret is
- *         negative, but NULL is given for @error, strerror() is used.
- *
- * Marks @job as completed. If @ret is non-zero, the job transaction it is part
- * of is aborted. If @ret is zero, the job moves into the WAITING state. If it
- * is the last job to complete in its transaction, all jobs in the transaction
- * move from WAITING to PENDING.
- */
-void job_completed(Job *job, int ret, Error *error);
-
 /** Asynchronously complete the specified @job. */
 void job_complete(Job *job, Error **errp);
 
@@ -553,23 +568,6 @@ void job_finalize(Job *job, Error **errp);
  */
 void job_dismiss(Job **job, Error **errp);
 
-typedef void JobDeferToMainLoopFn(Job *job, void *opaque);
-
-/**
- * @job: The job
- * @fn: The function to run in the main loop
- * @opaque: The opaque value that is passed to @fn
- *
- * This function must be called by the main job coroutine just before it
- * returns.  @fn is executed in the main loop with the job AioContext acquired.
- *
- * Block jobs must call bdrv_unref(), bdrv_close(), and anything that uses
- * bdrv_drain_all() in the main loop.
- *
- * The @job AioContext is held while @fn executes.
- */
-void job_defer_to_main_loop(Job *job, JobDeferToMainLoopFn *fn, void *opaque);
-
 /**
  * Synchronously finishes the given @job. If @finish is given, it is called to
  * trigger completion or cancellation of the job.