[Qemu-devel] [PATCH 2/8] block: add driver operation callbacks

[Liu Yuan <namei.unix@gmail.com>]

Driver operations are defined as callbacks passed from block upper drivers to
lower drivers and are supposed to be called by lower drivers.

Requests handling(queuing, submitting, etc.) are done in protocol tier in the
block layer and connection states are also maintained down there. Driver
operations are supposed to notify the upper tier (such as quorum) of the states
changes.

For now only two operation are added:

driver_disconnect: called when connection is off
driver_reconnect: called when connection is on after disconnection

Which are used to notify upper tier of the connection state.

Cc: Eric Blake <eblake@redhat.com>
Cc: Benoit Canet <benoit@irqsave.net>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
---
 block.c                   | 7 +++++++
 include/block/block.h     | 7 +++++++
 include/block/block_int.h | 3 +++
 3 files changed, 17 insertions(+)

diff --git a/block.c b/block.c
index c12b8de..22eb3e4 100644
--- a/block.c
+++ b/block.c
@@ -2152,6 +2152,13 @@ void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops,
     bs->dev_opaque = opaque;
 }
 
+void bdrv_set_drv_ops(BlockDriverState *bs, const BlockDrvOps *ops,
+                      void *opaque)
+{
+    bs->drv_ops = ops;
+    bs->drv_opaque = opaque;
+}
+
 static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load)
 {
     if (bs->dev_ops && bs->dev_ops->change_media_cb) {
diff --git a/include/block/block.h b/include/block/block.h
index 8f4ad16..a61eaf0 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -82,6 +82,11 @@ typedef struct BlockDevOps {
     void (*resize_cb)(void *opaque);
 } BlockDevOps;
 
+typedef struct BlockDrvOps {
+    void (*driver_reconnect)(BlockDriverState *bs);
+    void (*driver_disconnect)(BlockDriverState *bs);
+} BlockDrvOps;
+
 typedef enum {
     BDRV_REQ_COPY_ON_READ = 0x1,
     BDRV_REQ_ZERO_WRITE   = 0x2,
@@ -234,6 +239,8 @@ void bdrv_detach_dev(BlockDriverState *bs, void *dev);
 void *bdrv_get_attached_dev(BlockDriverState *bs);
 void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops,
                       void *opaque);
+void bdrv_set_drv_ops(BlockDriverState *bs, const BlockDrvOps *ops,
+                      void *opaque);
 void bdrv_dev_eject_request(BlockDriverState *bs, bool force);
 bool bdrv_dev_has_removable_media(BlockDriverState *bs);
 bool bdrv_dev_is_tray_open(BlockDriverState *bs);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 2334895..9fdec7f 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -319,6 +319,9 @@ struct BlockDriverState {
     const BlockDevOps *dev_ops;
     void *dev_opaque;
 
+    const BlockDrvOps *drv_ops;
+    void *drv_opaque;
+
     AioContext *aio_context; /* event loop used for fd handlers, timers, etc */
 
     char filename[1024];
-- 
1.9.1