diff options
| -rw-r--r-- | block.c | 23 | ||||
| -rw-r--r-- | include/block/block.h | 17 |
2 files changed, 40 insertions, 0 deletions
@@ -6303,6 +6303,29 @@ AioContext *bdrv_get_aio_context(BlockDriverState *bs) return bs ? bs->aio_context : qemu_get_aio_context(); } +AioContext *coroutine_fn bdrv_co_enter(BlockDriverState *bs) +{ + Coroutine *self = qemu_coroutine_self(); + AioContext *old_ctx = qemu_coroutine_get_aio_context(self); + AioContext *new_ctx; + + /* + * Increase bs->in_flight to ensure that this operation is completed before + * moving the node to a different AioContext. Read new_ctx only afterwards. + */ + bdrv_inc_in_flight(bs); + + new_ctx = bdrv_get_aio_context(bs); + aio_co_reschedule_self(new_ctx); + return old_ctx; +} + +void coroutine_fn bdrv_co_leave(BlockDriverState *bs, AioContext *old_ctx) +{ + aio_co_reschedule_self(old_ctx); + bdrv_dec_in_flight(bs); +} + void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co) { aio_co_enter(bdrv_get_aio_context(bs), co); diff --git a/include/block/block.h b/include/block/block.h index ce2ac39299..1027c58a41 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -641,6 +641,23 @@ bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag); AioContext *bdrv_get_aio_context(BlockDriverState *bs); /** + * Move the current coroutine to the AioContext of @bs and return the old + * AioContext of the coroutine. Increase bs->in_flight so that draining @bs + * will wait for the operation to proceed until the corresponding + * bdrv_co_leave(). + * + * Consequently, you can't call drain inside a bdrv_co_enter/leave() section as + * this will deadlock. + */ +AioContext *coroutine_fn bdrv_co_enter(BlockDriverState *bs); + +/** + * Ends a section started by bdrv_co_enter(). Move the current coroutine back + * to old_ctx and decrease bs->in_flight again. + */ +void coroutine_fn bdrv_co_leave(BlockDriverState *bs, AioContext *old_ctx); + +/** * Transfer control to @co in the aio context of @bs */ void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co); |