[Qemu-devel] [PATCH 08/10] blockjob: Propagate AioContext change to all job nodes

[Kevin Wolf <kwolf@redhat.com>]

Block jobs require that all of the nodes the job is using are in the
same AioContext. Therefore all BdrvChild objects of the job propagate
.(can_)set_aio_context to all other job nodes, so that the switch is
checked and performed consistently even if both nodes are in different
subtrees.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/backup.c |  8 --------
 block/mirror.c | 10 +---------
 blockjob.c     | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 17 deletions(-)

diff --git a/block/backup.c b/block/backup.c
index 910ed764aa..916817d8b1 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -300,13 +300,6 @@ static void backup_clean(Job *job)
     s->target = NULL;
 }
 
-static void backup_attached_aio_context(BlockJob *job, AioContext *aio_context)
-{
-    BackupBlockJob *s = container_of(job, BackupBlockJob, common);
-
-    blk_set_aio_context(s->target, aio_context);
-}
-
 void backup_do_checkpoint(BlockJob *job, Error **errp)
 {
     BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
@@ -558,7 +551,6 @@ static const BlockJobDriver backup_job_driver = {
         .abort                  = backup_abort,
         .clean                  = backup_clean,
     },
-    .attached_aio_context   = backup_attached_aio_context,
     .drain                  = backup_drain,
 };
 
diff --git a/block/mirror.c b/block/mirror.c
index ff15cfb197..ec4bd9f404 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1142,13 +1142,6 @@ static bool mirror_drained_poll(BlockJob *job)
     return !!s->in_flight;
 }
 
-static void mirror_attached_aio_context(BlockJob *job, AioContext *new_context)
-{
-    MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
-
-    blk_set_aio_context(s->target, new_context);
-}
-
 static void mirror_drain(BlockJob *job)
 {
     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
@@ -1178,7 +1171,6 @@ static const BlockJobDriver mirror_job_driver = {
         .complete               = mirror_complete,
     },
     .drained_poll           = mirror_drained_poll,
-    .attached_aio_context   = mirror_attached_aio_context,
     .drain                  = mirror_drain,
 };
 
@@ -1196,7 +1188,6 @@ static const BlockJobDriver commit_active_job_driver = {
         .complete               = mirror_complete,
     },
     .drained_poll           = mirror_drained_poll,
-    .attached_aio_context   = mirror_attached_aio_context,
     .drain                  = mirror_drain,
 };
 
@@ -1612,6 +1603,7 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs,
          * ensure that. */
         blk_set_force_allow_inactivate(s->target);
     }
+    blk_set_allow_aio_context_change(s->target, true);
 
     s->replaces = g_strdup(replaces);
     s->on_source_error = on_source_error;
diff --git a/blockjob.c b/blockjob.c
index 730101d282..24e6093a9c 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -183,11 +183,44 @@ static void child_job_drained_end(BdrvChild *c)
     job_resume(&job->job);
 }
 
+static bool child_job_can_set_aio_ctx(BdrvChild *c, AioContext *ctx,
+                                      GSList **ignore, Error **errp)
+{
+    BlockJob *job = c->opaque;
+    GSList *l;
+
+    for (l = job->nodes; l; l = l->next) {
+        BdrvChild *sibling = l->data;
+        if (!bdrv_child_can_set_aio_context(sibling, ctx, ignore, errp)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+static void child_job_set_aio_ctx(BdrvChild *c, AioContext *ctx,
+                                  GSList **ignore)
+{
+    BlockJob *job = c->opaque;
+    GSList *l;
+
+    for (l = job->nodes; l; l = l->next) {
+        BdrvChild *sibling = l->data;
+        if (g_slist_find(*ignore, sibling)) {
+            continue;
+        }
+        *ignore = g_slist_prepend(*ignore, sibling);
+        bdrv_set_aio_context_ignore(sibling->bs, ctx, ignore);
+    }
+}
+
 static const BdrvChildRole child_job = {
     .get_parent_desc    = child_job_get_parent_desc,
     .drained_begin      = child_job_drained_begin,
     .drained_poll       = child_job_drained_poll,
     .drained_end        = child_job_drained_end,
+    .can_set_aio_ctx    = child_job_can_set_aio_ctx,
+    .set_aio_ctx        = child_job_set_aio_ctx,
     .stay_at_node       = true,
 };
 
@@ -440,6 +473,7 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 
     blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
                                  block_job_detach_aio_context, job);
+    blk_set_allow_aio_context_change(blk, true);
 
     /* Only set speed when necessary to avoid NotSupported error */
     if (speed != 0) {
-- 
2.20.1