[PATCH v2 06/36] block: BdrvChildClass: add .get_parent_aio_context handler

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Add new handler to get aio context and implement it in all child
classes. Add corresponding public interface to be used soon.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 include/block/block.h     |  3 +++
 include/block/block_int.h |  2 ++
 block.c                   | 13 +++++++++++++
 block/block-backend.c     |  9 +++++++++
 blockjob.c                |  8 ++++++++
 5 files changed, 35 insertions(+)

diff --git a/include/block/block.h b/include/block/block.h
index 550c5a7513..6788ccd25b 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -688,6 +688,9 @@ bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
                               GSList **ignore, Error **errp);
 int bdrv_parent_try_set_aio_context(BdrvChild *c, AioContext *ctx,
                                     Error **errp);
+
+AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c);
+
 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
 
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 9138aaf5ec..943fd855fe 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -772,6 +772,8 @@ struct BdrvChildClass {
     bool (*can_set_aio_ctx)(BdrvChild *child, AioContext *ctx,
                             GSList **ignore, Error **errp);
     void (*set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore);
+
+    AioContext *(*get_parent_aio_context)(BdrvChild *child);
 };
 
 extern const BdrvChildClass child_of_bds;
diff --git a/block.c b/block.c
index 5d925c208d..95d3684d8d 100644
--- a/block.c
+++ b/block.c
@@ -1334,6 +1334,13 @@ static int bdrv_child_cb_update_filename(BdrvChild *c, BlockDriverState *base,
     return 0;
 }
 
+static AioContext *bdrv_child_cb_get_parent_aio_context(BdrvChild *c)
+{
+    BlockDriverState *bs = c->opaque;
+
+    return bdrv_get_aio_context(bs);
+}
+
 const BdrvChildClass child_of_bds = {
     .parent_is_bds   = true,
     .get_parent_desc = bdrv_child_get_parent_desc,
@@ -1347,8 +1354,14 @@ const BdrvChildClass child_of_bds = {
     .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
     .set_aio_ctx     = bdrv_child_cb_set_aio_ctx,
     .update_filename = bdrv_child_cb_update_filename,
+    .get_parent_aio_context = bdrv_child_cb_get_parent_aio_context,
 };
 
+AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c)
+{
+    return c->klass->get_parent_aio_context(c);
+}
+
 static int bdrv_open_flags(BlockDriverState *bs, int flags)
 {
     int open_flags = flags;
diff --git a/block/block-backend.c b/block/block-backend.c
index ce78d30794..28efa0dff3 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -298,6 +298,13 @@ static void blk_root_detach(BdrvChild *child)
     }
 }
 
+static AioContext *blk_root_get_parent_aio_context(BdrvChild *c)
+{
+    BlockBackend *blk = c->opaque;
+
+    return blk_get_aio_context(blk);
+}
+
 static const BdrvChildClass child_root = {
     .inherit_options    = blk_root_inherit_options,
 
@@ -318,6 +325,8 @@ static const BdrvChildClass child_root = {
 
     .can_set_aio_ctx    = blk_root_can_set_aio_ctx,
     .set_aio_ctx        = blk_root_set_aio_ctx,
+
+    .get_parent_aio_context = blk_root_get_parent_aio_context,
 };
 
 /*
diff --git a/blockjob.c b/blockjob.c
index 9d0bed01c2..f671763c2c 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -163,6 +163,13 @@ static void child_job_set_aio_ctx(BdrvChild *c, AioContext *ctx,
     job->job.aio_context = ctx;
 }
 
+static AioContext *child_job_get_parent_aio_context(BdrvChild *c)
+{
+    BlockJob *job = c->opaque;
+
+    return job->job.aio_context;
+}
+
 static const BdrvChildClass child_job = {
     .get_parent_desc    = child_job_get_parent_desc,
     .drained_begin      = child_job_drained_begin,
@@ -171,6 +178,7 @@ static const BdrvChildClass child_job = {
     .can_set_aio_ctx    = child_job_can_set_aio_ctx,
     .set_aio_ctx        = child_job_set_aio_ctx,
     .stay_at_node       = true,
+    .get_parent_aio_context = child_job_get_parent_aio_context,
 };
 
 void block_job_remove_all_bdrv(BlockJob *job)
-- 
2.21.3