1eebdab3c3
Introduce the aio_add_sqe() API for submitting io_uring requests in the current AioContext. This allows other components in QEMU, like the block layer, to take advantage of io_uring features without creating their own io_uring context. This API supports nested event loops just like file descriptor monitoring and BHs do. This comes at a complexity cost: CQE callbacks must be placed on a list so that nested event loops can invoke pending CQE callbacks from parent event loops. If you're wondering why CqeHandler exists instead of just a callback function pointer, this is why. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-ID: <20251104022933.618123-14-stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
81 lines
2.2 KiB
C
81 lines
2.2 KiB
C
/*
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* AioContext POSIX event loop implementation internal APIs
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*
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* Copyright IBM, Corp. 2008
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* Copyright Red Hat, Inc. 2020
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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* Contributions after 2012-01-13 are licensed under the terms of the
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* GNU GPL, version 2 or (at your option) any later version.
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*/
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#ifndef AIO_POSIX_H
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#define AIO_POSIX_H
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#include "block/aio.h"
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#include "qapi/error.h"
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struct AioHandler {
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GPollFD pfd;
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IOHandler *io_read;
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IOHandler *io_write;
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AioPollFn *io_poll;
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IOHandler *io_poll_ready;
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IOHandler *io_poll_begin;
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IOHandler *io_poll_end;
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void *opaque;
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QLIST_ENTRY(AioHandler) node;
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QLIST_ENTRY(AioHandler) node_ready; /* only used during aio_poll() */
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QLIST_ENTRY(AioHandler) node_deleted;
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QLIST_ENTRY(AioHandler) node_poll;
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#ifdef CONFIG_LINUX_IO_URING
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QSLIST_ENTRY(AioHandler) node_submitted;
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unsigned flags; /* see fdmon-io_uring.c */
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CqeHandler internal_cqe_handler; /* used for POLL_ADD/POLL_REMOVE */
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#endif
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int64_t poll_idle_timeout; /* when to stop userspace polling */
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bool poll_ready; /* has polling detected an event? */
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AioPolledEvent poll;
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};
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/* Add a handler to a ready list */
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void aio_add_ready_handler(AioHandlerList *ready_list, AioHandler *node,
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int revents);
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extern const FDMonOps fdmon_poll_ops;
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/* Switch back to poll(2). list_lock must be held. */
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void fdmon_poll_downgrade(AioContext *ctx);
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#ifdef CONFIG_EPOLL_CREATE1
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bool fdmon_epoll_try_upgrade(AioContext *ctx, unsigned npfd);
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void fdmon_epoll_setup(AioContext *ctx);
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/* list_lock must be held */
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void fdmon_epoll_disable(AioContext *ctx);
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#else
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static inline bool fdmon_epoll_try_upgrade(AioContext *ctx, unsigned npfd)
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{
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return false;
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}
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static inline void fdmon_epoll_setup(AioContext *ctx)
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{
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}
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static inline void fdmon_epoll_disable(AioContext *ctx)
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{
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}
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#endif /* !CONFIG_EPOLL_CREATE1 */
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#ifdef CONFIG_LINUX_IO_URING
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bool fdmon_io_uring_setup(AioContext *ctx, Error **errp);
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void fdmon_io_uring_destroy(AioContext *ctx);
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#endif /* !CONFIG_LINUX_IO_URING */
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#endif /* AIO_POSIX_H */
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