2005-04-17 06:20:36 +08:00
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#ifndef __LINUX__AIO_H
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#define __LINUX__AIO_H
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#include <linux/list.h>
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#include <linux/workqueue.h>
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#include <linux/aio_abi.h>
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2006-10-01 14:28:46 +08:00
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#include <linux/uio.h>
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2008-12-09 15:11:22 +08:00
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#include <linux/rcupdate.h>
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2005-04-17 06:20:36 +08:00
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2011-07-27 07:09:06 +08:00
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#include <linux/atomic.h>
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2005-04-17 06:20:36 +08:00
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struct kioctx;
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2013-05-08 07:18:49 +08:00
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struct kiocb;
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2005-04-17 06:20:36 +08:00
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2013-05-08 07:19:10 +08:00
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#define KIOCB_KEY 0
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2005-04-17 06:20:36 +08:00
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2013-05-08 07:18:49 +08:00
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/*
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* We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either
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* cancelled or completed (this makes a certain amount of sense because
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* successful cancellation - io_cancel() - does deliver the completion to
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* userspace).
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*
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* And since most things don't implement kiocb cancellation and we'd really like
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* kiocb completion to be lockless when possible, we use ki_cancel to
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* synchronize cancellation and completion - we only set it to KIOCB_CANCELLED
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* with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel().
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*/
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#define KIOCB_CANCELLED ((void *) (~0ULL))
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2005-04-17 06:20:36 +08:00
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2013-05-14 05:45:08 +08:00
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typedef int (kiocb_cancel_fn)(struct kiocb *);
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2005-04-17 06:20:36 +08:00
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struct kiocb {
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struct file *ki_filp;
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2013-05-08 07:19:10 +08:00
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struct kioctx *ki_ctx; /* NULL for sync ops */
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2013-05-08 07:18:49 +08:00
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kiocb_cancel_fn *ki_cancel;
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2013-02-26 08:36:27 +08:00
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void *private;
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2005-04-17 06:20:36 +08:00
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union {
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void __user *user;
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struct task_struct *tsk;
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} ki_obj;
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2006-01-08 17:04:34 +08:00
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2005-04-17 06:20:36 +08:00
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__u64 ki_user_data; /* user's data for completion */
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loff_t ki_pos;
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2013-02-26 08:36:27 +08:00
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size_t ki_nbytes; /* copy of iocb->aio_nbytes */
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2005-04-17 06:20:36 +08:00
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2006-01-08 17:04:34 +08:00
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struct list_head ki_list; /* the aio core uses this
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* for cancellation */
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signal/timer/event: KAIO eventfd support example
This is an example about how to add eventfd support to the current KAIO code,
in order to enable KAIO to post readiness events to a pollable fd (hence
compatible with POSIX select/poll). The KAIO code simply signals the eventfd
fd when events are ready, and this triggers a POLLIN in the fd. This patch
uses a reserved for future use member of the struct iocb to pass an eventfd
file descriptor, that KAIO will use to post events every time a request
completes. At that point, an aio_getevents() will return the completed result
to a struct io_event. I made a quick test program to verify the patch, and it
runs fine here:
http://www.xmailserver.org/eventfd-aio-test.c
The test program uses poll(2), but it'd, of course, work with select and epoll
too.
This can allow to schedule both block I/O and other poll-able devices
requests, and wait for results using select/poll/epoll. In a typical
scenario, an application would submit KAIO request using aio_submit(), and
will also use epoll_ctl() on the whole other class of devices (that with the
addition of signals, timers and user events, now it's pretty much complete),
and then would:
epoll_wait(...);
for_each_event {
if (curr_event_is_kaiofd) {
aio_getevents();
dispatch_aio_events();
} else {
dispatch_epoll_event();
}
}
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:21 +08:00
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/*
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* If the aio_resfd field of the userspace iocb is not zero,
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2009-07-01 02:41:11 +08:00
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* this is the underlying eventfd context to deliver events to.
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signal/timer/event: KAIO eventfd support example
This is an example about how to add eventfd support to the current KAIO code,
in order to enable KAIO to post readiness events to a pollable fd (hence
compatible with POSIX select/poll). The KAIO code simply signals the eventfd
fd when events are ready, and this triggers a POLLIN in the fd. This patch
uses a reserved for future use member of the struct iocb to pass an eventfd
file descriptor, that KAIO will use to post events every time a request
completes. At that point, an aio_getevents() will return the completed result
to a struct io_event. I made a quick test program to verify the patch, and it
runs fine here:
http://www.xmailserver.org/eventfd-aio-test.c
The test program uses poll(2), but it'd, of course, work with select and epoll
too.
This can allow to schedule both block I/O and other poll-able devices
requests, and wait for results using select/poll/epoll. In a typical
scenario, an application would submit KAIO request using aio_submit(), and
will also use epoll_ctl() on the whole other class of devices (that with the
addition of signals, timers and user events, now it's pretty much complete),
and then would:
epoll_wait(...);
for_each_event {
if (curr_event_is_kaiofd) {
aio_getevents();
dispatch_aio_events();
} else {
dispatch_epoll_event();
}
}
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:21 +08:00
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*/
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2009-07-01 02:41:11 +08:00
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struct eventfd_ctx *ki_eventfd;
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2005-04-17 06:20:36 +08:00
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};
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2012-07-31 05:42:56 +08:00
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static inline bool is_sync_kiocb(struct kiocb *kiocb)
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{
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2013-05-08 07:19:10 +08:00
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return kiocb->ki_ctx == NULL;
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2012-07-31 05:42:56 +08:00
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}
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static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
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{
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*kiocb = (struct kiocb) {
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2013-05-08 07:19:10 +08:00
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.ki_ctx = NULL,
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2012-07-31 05:42:56 +08:00
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.ki_filp = filp,
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.ki_obj.tsk = current,
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};
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}
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2005-04-17 06:20:36 +08:00
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/* prototypes */
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2008-10-16 13:05:12 +08:00
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#ifdef CONFIG_AIO
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2008-02-14 07:03:15 +08:00
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extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb);
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2013-05-08 07:18:29 +08:00
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extern void aio_complete(struct kiocb *iocb, long res, long res2);
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2005-04-17 06:20:36 +08:00
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struct mm_struct;
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2008-02-14 07:03:15 +08:00
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extern void exit_aio(struct mm_struct *mm);
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2010-05-27 05:44:26 +08:00
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extern long do_io_submit(aio_context_t ctx_id, long nr,
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struct iocb __user *__user *iocbpp, bool compat);
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2013-05-08 07:18:49 +08:00
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void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel);
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2008-10-16 13:05:12 +08:00
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#else
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static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
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2013-05-08 07:18:29 +08:00
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static inline void aio_complete(struct kiocb *iocb, long res, long res2) { }
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2008-10-16 13:05:12 +08:00
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struct mm_struct;
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static inline void exit_aio(struct mm_struct *mm) { }
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2010-05-27 05:44:26 +08:00
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static inline long do_io_submit(aio_context_t ctx_id, long nr,
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struct iocb __user * __user *iocbpp,
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bool compat) { return 0; }
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2013-05-08 07:18:49 +08:00
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static inline void kiocb_set_cancel_fn(struct kiocb *req,
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kiocb_cancel_fn *cancel) { }
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2008-10-16 13:05:12 +08:00
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#endif /* CONFIG_AIO */
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2005-04-17 06:20:36 +08:00
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static inline struct kiocb *list_kiocb(struct list_head *h)
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{
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return list_entry(h, struct kiocb, ki_list);
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}
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/* for sysctl: */
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2005-11-07 16:59:31 +08:00
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extern unsigned long aio_nr;
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extern unsigned long aio_max_nr;
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2005-04-17 06:20:36 +08:00
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#endif /* __LINUX__AIO_H */
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