[2/9] block: User BdrvChild callback for device name

Commit Message

Kevin Wolf March 22, 2016, 7:36 p.m. UTC

In order to get rid of bs->blk for bdrv_get_device_name() and
bdrv_get_device_or_node_name(), ask all parents for their name and
simply pick the first one.

Signed-off-by: Kevin Wolf <[e-mail]>
---
 block.c                   | 22 ++++++++++++++++++++--
 block/block-backend.c     |  6 ++++++
 include/block/block_int.h |  1 +
 3 files changed, 27 insertions(+), 2 deletions(-)

Comments

Max Reitz March 29, 2016, 5:43 p.m. UTC | #1

On 22.03.2016 20:36, Kevin Wolf wrote:
> In order to get rid of bs->blk for bdrv_get_device_name() and
> bdrv_get_device_or_node_name(), ask all parents for their name and
> simply pick the first one.
> 
> Signed-off-by: Kevin Wolf <[e-mail]>
> ---
>  block.c                   | 22 ++++++++++++++++++++--
>  block/block-backend.c     |  6 ++++++
>  include/block/block_int.h |  1 +
>  3 files changed, 27 insertions(+), 2 deletions(-)

[...]

> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index f60cb7c..195abe8 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -358,6 +358,7 @@ struct BdrvChildRole {
>  
>      void (*change_media)(BdrvChild *child, bool load);
>      void (*resize)(BdrvChild *child);
> +    const char* (*get_name)(BdrvChild *child);
>  
>      bool (*drain_queue)(BdrvChild *child);
>  };

I wouldn't mind an explanation there what this is supposed to be used
for. From the name alone I'd expect a parent BDS to return its node name.

Reviewed-by: Max Reitz <[e-mail]>

Patch

diff --git a/block.c b/block.c
index 1fb5dac..4cc117d 100644
--- a/block.c
+++ b/block.c
@@ -2924,10 +2924,28 @@  const char *bdrv_get_node_name(const BlockDriverState *bs)
     return bs->node_name;
 }
 
+static const char *bdrv_get_parent_name(const BlockDriverState *bs)
+{
+    BdrvChild *c;
+    const char *name;
+
+    /* If multiple parents have a name, just pick the first one. */
+    QLIST_FOREACH(c, &bs->parents, next_parent) {
+        if (c->role->get_name) {
+            name = c->role->get_name(c);
+            if (name && *name) {
+                return name;
+            }
+        }
+    }
+
+    return NULL;
+}
+
 /* TODO check what callers really want: bs->node_name or blk_name() */
 const char *bdrv_get_device_name(const BlockDriverState *bs)
 {
-    return bs->blk ? blk_name(bs->blk) : "";
+    return bdrv_get_parent_name(bs) ?: "";
 }
 
 /* This can be used to identify nodes that might not have a device
@@ -2936,7 +2954,7 @@  const char *bdrv_get_device_name(const BlockDriverState *bs)
  * absent, then this returns an empty (non-null) string. */
 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs)
 {
-    return bs->blk ? blk_name(bs->blk) : bs->node_name;
+    return bdrv_get_parent_name(bs) ?: bs->node_name;
 }
 
 int bdrv_get_flags(BlockDriverState *bs)
diff --git a/block/block-backend.c b/block/block-backend.c
index 9d973ba..c4c0dc0 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -95,11 +95,17 @@  static bool blk_drain_throttling_queue(BdrvChild *child);
 static void blk_root_change_media(BdrvChild *child, bool load);
 static void blk_root_resize(BdrvChild *child);
 
+static const char *blk_root_get_name(BdrvChild *child)
+{
+    return blk_name(child->opaque);
+}
+
 static const BdrvChildRole child_root = {
     .inherit_options    = blk_root_inherit_options,
 
     .change_media       = blk_root_change_media,
     .resize             = blk_root_resize,
+    .get_name           = blk_root_get_name,
 
     .drain_queue        = blk_drain_throttling_queue,
 };
diff --git a/include/block/block_int.h b/include/block/block_int.h
index f60cb7c..195abe8 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -358,6 +358,7 @@  struct BdrvChildRole {
 
     void (*change_media)(BdrvChild *child, bool load);
     void (*resize)(BdrvChild *child);
+    const char* (*get_name)(BdrvChild *child);
 
     bool (*drain_queue)(BdrvChild *child);
 };