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[Qemu-block] [PATCH v2 02/13] block: Introduce BlockBackendPublic
From: |
Kevin Wolf |
Subject: |
[Qemu-block] [PATCH v2 02/13] block: Introduce BlockBackendPublic |
Date: |
Fri, 22 Apr 2016 19:42:31 +0200 |
Some features, like I/O throttling, are implemented outside
block-backend.c, but still want to keep information in BlockBackend,
e.g. list entries that allow keeping a list of BlockBackends.
In order to avoid exposing the whole struct layout in the public header
file, this patch introduces an embedded public struct where such
information can be added and a pair of functions to convert between
BlockBackend and BlockBackendPublic.
Signed-off-by: Kevin Wolf <address@hidden>
---
block/block-backend.c | 17 +++++++++++++++++
include/sysemu/block-backend.h | 10 ++++++++++
2 files changed, 27 insertions(+)
diff --git a/block/block-backend.c b/block/block-backend.c
index e4839ca..34798a4 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -34,6 +34,7 @@ struct BlockBackend {
DriveInfo *legacy_dinfo; /* null unless created by drive_new() */
QTAILQ_ENTRY(BlockBackend) link; /* for block_backends */
QTAILQ_ENTRY(BlockBackend) monitor_link; /* for monitor_block_backends */
+ BlockBackendPublic public;
void *dev; /* attached device model, if any */
/* TODO change to DeviceState when all users are qdevified */
@@ -411,6 +412,22 @@ BlockBackend *blk_by_legacy_dinfo(DriveInfo *dinfo)
}
/*
+ * Returns a pointer to the publicly accessible fields of @blk.
+ */
+BlockBackendPublic *blk_get_public(BlockBackend *blk)
+{
+ return &blk->public;
+}
+
+/*
+ * Returns a BlockBackend given the associated @public fields.
+ */
+BlockBackend *blk_by_public(BlockBackendPublic *public)
+{
+ return container_of(public, BlockBackend, public);
+}
+
+/*
* Disassociates the currently associated BlockDriverState from @blk.
*/
void blk_remove_bs(BlockBackend *blk)
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index c62b6fe..3915ee7 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -59,6 +59,13 @@ typedef struct BlockDevOps {
void (*resize_cb)(void *opaque);
} BlockDevOps;
+/* This struct is embedded in (the private) BlockBackend struct and contains
+ * fields that must be public. This is in particular for QLIST_ENTRY() and
+ * friends so that BlockBackends can be kept in lists outside block-backend.c
*/
+typedef struct BlockBackendPublic {
+ int dummy; /* empty structs are illegal */
+} BlockBackendPublic;
+
BlockBackend *blk_new(Error **errp);
BlockBackend *blk_new_with_bs(Error **errp);
BlockBackend *blk_new_open(const char *filename, const char *reference,
@@ -74,6 +81,9 @@ BlockDriverState *blk_next_root_bs(BlockDriverState *bs);
bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp);
void monitor_remove_blk(BlockBackend *blk);
+BlockBackendPublic *blk_get_public(BlockBackend *blk);
+BlockBackend *blk_by_public(BlockBackendPublic *public);
+
BlockDriverState *blk_bs(BlockBackend *blk);
void blk_remove_bs(BlockBackend *blk);
void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs);
--
1.8.3.1
- [Qemu-block] [PATCH v2 00/13] block: Move I/O throttling to BlockBackend, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 01/13] block: Make sure throttled BDSes always have a BB, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 02/13] block: Introduce BlockBackendPublic,
Kevin Wolf <=
- [Qemu-block] [PATCH v2 03/13] block: throttle-groups: Use BlockBackend pointers internally, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 04/13] block: Convert throttle_group_get_name() to BlockBackend, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 06/13] block: Move actual I/O throttling to BlockBackend, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 05/13] block: Move throttling fields from BDS to BB, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 07/13] block: Move I/O throttling configuration functions to BlockBackend, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 08/13] block: Introduce BdrvChild.opaque, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 10/13] block: Decouple throttling from BlockDriverState, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 09/13] block: Drain throttling queue with BdrvChild callback, Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 11/13] block: Remove bdrv_move_feature_fields(), Kevin Wolf, 2016/04/22
- [Qemu-block] [PATCH v2 12/13] Revert "block: Forbid I/O throttling on nodes with multiple parents for 2.6", Kevin Wolf, 2016/04/22