From 33384421b3abe74555baeaf788b17204cd8c6080 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Fri, 20 Jun 2014 21:57:33 +0200 Subject: block: Add AIO context notifiers 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 Reviewed-by: Stefan Hajnoczi Signed-off-by: Stefan Hajnoczi --- include/block/block_int.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'include/block') diff --git a/include/block/block_int.h b/include/block/block_int.h index 233489547e..8a61215ac0 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 -- cgit v1.2.1