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[Qemu-devel] [PULL 24/35] block: Add AIO context notifiers
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 24/35] block: Add AIO context notifiers |
Date: |
Fri, 29 Aug 2014 17:29:52 +0100 |
From: Max Reitz <address@hidden>
If a long-running operation on a BDS wants to always remain in the same
AIO context, it somehow needs to keep track of the BDS changing its
context. This adds a function for registering callbacks on a BDS which
are called whenever the BDS is attached or detached from an AIO context.
Signed-off-by: Max Reitz <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++
include/block/block_int.h | 41 ++++++++++++++++++++++++++++++++++
2 files changed, 97 insertions(+)
diff --git a/block.c b/block.c
index 1df13ac..9c5566b 100644
--- a/block.c
+++ b/block.c
@@ -1819,6 +1819,8 @@ void bdrv_reopen_abort(BDRVReopenState *reopen_state)
void bdrv_close(BlockDriverState *bs)
{
+ BdrvAioNotifier *ban, *ban_next;
+
if (bs->job) {
block_job_cancel_sync(bs->job);
}
@@ -1863,6 +1865,11 @@ void bdrv_close(BlockDriverState *bs)
if (bs->io_limits_enabled) {
bdrv_io_limits_disable(bs);
}
+
+ QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
+ g_free(ban);
+ }
+ QLIST_INIT(&bs->aio_notifiers);
}
void bdrv_close_all(void)
@@ -5729,10 +5736,16 @@ AioContext *bdrv_get_aio_context(BlockDriverState *bs)
void bdrv_detach_aio_context(BlockDriverState *bs)
{
+ BdrvAioNotifier *baf;
+
if (!bs->drv) {
return;
}
+ QLIST_FOREACH(baf, &bs->aio_notifiers, list) {
+ baf->detach_aio_context(baf->opaque);
+ }
+
if (bs->io_limits_enabled) {
throttle_detach_aio_context(&bs->throttle_state);
}
@@ -5752,6 +5765,8 @@ void bdrv_detach_aio_context(BlockDriverState *bs)
void bdrv_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
+ BdrvAioNotifier *ban;
+
if (!bs->drv) {
return;
}
@@ -5770,6 +5785,10 @@ void bdrv_attach_aio_context(BlockDriverState *bs,
if (bs->io_limits_enabled) {
throttle_attach_aio_context(&bs->throttle_state, new_context);
}
+
+ QLIST_FOREACH(ban, &bs->aio_notifiers, list) {
+ ban->attached_aio_context(new_context, ban->opaque);
+ }
}
void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
@@ -5786,6 +5805,43 @@ void bdrv_set_aio_context(BlockDriverState *bs,
AioContext *new_context)
aio_context_release(new_context);
}
+void bdrv_add_aio_context_notifier(BlockDriverState *bs,
+ void (*attached_aio_context)(AioContext *new_context, void *opaque),
+ void (*detach_aio_context)(void *opaque), void *opaque)
+{
+ BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1);
+ *ban = (BdrvAioNotifier){
+ .attached_aio_context = attached_aio_context,
+ .detach_aio_context = detach_aio_context,
+ .opaque = opaque
+ };
+
+ QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list);
+}
+
+void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
+ void (*attached_aio_context)(AioContext
*,
+ void *),
+ void (*detach_aio_context)(void *),
+ void *opaque)
+{
+ BdrvAioNotifier *ban, *ban_next;
+
+ QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) {
+ if (ban->attached_aio_context == attached_aio_context &&
+ ban->detach_aio_context == detach_aio_context &&
+ ban->opaque == opaque)
+ {
+ QLIST_REMOVE(ban, list);
+ g_free(ban);
+
+ return;
+ }
+ }
+
+ abort();
+}
+
void bdrv_add_before_write_notifier(BlockDriverState *bs,
NotifierWithReturn *notifier)
{
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 2334895..8a61215 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -294,6 +294,15 @@ typedef struct BlockLimits {
typedef struct BdrvOpBlocker BdrvOpBlocker;
+typedef struct BdrvAioNotifier {
+ void (*attached_aio_context)(AioContext *new_context, void *opaque);
+ void (*detach_aio_context)(void *opaque);
+
+ void *opaque;
+
+ QLIST_ENTRY(BdrvAioNotifier) list;
+} BdrvAioNotifier;
+
/*
* Note: the function bdrv_append() copies and swaps contents of
* BlockDriverStates, so if you add new fields to this struct, please
@@ -320,6 +329,10 @@ struct BlockDriverState {
void *dev_opaque;
AioContext *aio_context; /* event loop used for fd handlers, timers, etc */
+ /* long-running tasks intended to always use the same AioContext as this
+ * BDS may register themselves in this list to be notified of changes
+ * regarding this BDS's context */
+ QLIST_HEAD(, BdrvAioNotifier) aio_notifiers;
char filename[1024];
char backing_file[1024]; /* if non zero, the image is a diff of
@@ -437,6 +450,34 @@ void bdrv_detach_aio_context(BlockDriverState *bs);
void bdrv_attach_aio_context(BlockDriverState *bs,
AioContext *new_context);
+/**
+ * bdrv_add_aio_context_notifier:
+ *
+ * If a long-running job intends to be always run in the same AioContext as a
+ * certain BDS, it may use this function to be notified of changes regarding
the
+ * association of the BDS to an AioContext.
+ *
+ * attached_aio_context() is called after the target BDS has been attached to a
+ * new AioContext; detach_aio_context() is called before the target BDS is
being
+ * detached from its old AioContext.
+ */
+void bdrv_add_aio_context_notifier(BlockDriverState *bs,
+ void (*attached_aio_context)(AioContext *new_context, void *opaque),
+ void (*detach_aio_context)(void *opaque), void *opaque);
+
+/**
+ * bdrv_remove_aio_context_notifier:
+ *
+ * Unsubscribe of change notifications regarding the BDS's AioContext. The
+ * parameters given here have to be the same as those given to
+ * bdrv_add_aio_context_notifier().
+ */
+void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
+ void (*aio_context_attached)(AioContext
*,
+ void *),
+ void (*aio_context_detached)(void *),
+ void *opaque);
+
#ifdef _WIN32
int is_windows_drive(const char *filename);
#endif
--
1.9.3
- [Qemu-devel] [PULL 14/35] aio-win32: Factor out duplicate code into aio_dispatch_handlers, (continued)
- [Qemu-devel] [PULL 14/35] aio-win32: Factor out duplicate code into aio_dispatch_handlers, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 15/35] AioContext: run bottom halves after polling, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 16/35] AioContext: export and use aio_dispatch, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 17/35] test-aio: test timers on Windows too, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 18/35] aio-win32: add aio_set_dispatching optimization, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 19/35] AioContext: introduce aio_prepare, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 20/35] qemu-coroutine-io: fix for Win32, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 22/35] sheepdog: fix a core dump while do auto-reconnecting, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 21/35] aio-win32: add support for sockets, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 23/35] nbd: Drop nbd_can_read(), Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 24/35] block: Add AIO context notifiers,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 26/35] block: fix overlapping multiwrite requests, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 27/35] qemu-iotests: add multiwrite test cases, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 25/35] nbd: Follow the BDS' AIO context, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 29/35] block: acquire AioContext in do_drive_del(), Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 28/35] linux-aio: avoid deadlock in nested aio_poll() calls, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 30/35] virtio-blk: allow drive_del with dataplane, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 32/35] curl: Don't deref NULL pointer in call to aio_poll., Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 33/35] nfs: Fix leak of opts in nfs_file_open, Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 31/35] curl: Allow a cookie or cookies to be sent with http/https requests., Stefan Hajnoczi, 2014/08/29
- [Qemu-devel] [PULL 34/35] blkverify: Fix leak of opts in blkverify_open, Stefan Hajnoczi, 2014/08/29