/*

 * libaio engine

 *

 * IO engine using the Linux native aio interface.

 *

 */

#include <stdlib.h>

#include <unistd.h>

#include <errno.h>

#include <libaio.h>

#include <sys/time.h>

#include <sys/resource.h>

#include "../fio.h"

#include "../lib/pow2.h"

#include "../optgroup.h"

#include "../lib/memalign.h"

/* Should be defined in newest aio_abi.h */

#ifndef IOCB_FLAG_IOPRIO

#define IOCB_FLAG_IOPRIO    (1 << 1)

#endif

static int fio_libaio_commit(struct thread_data *td);

static int fio_libaio_init(struct thread_data *td);

struct libaio_data {

	io_context_t aio_ctx;

	struct io_event *aio_events;

	struct iocb **iocbs;

	struct io_u **io_us;

	struct io_u **io_u_index;

	/*

	 * Basic ring buffer. 'head' is incremented in _queue(), and

	 * 'tail' is incremented in _commit(). We keep 'queued' so

	 * that we know if the ring is full or empty, when

	 * 'head' == 'tail'. 'entries' is the ring size, and

	 * 'is_pow2' is just an optimization to use AND instead of

	 * modulus to get the remainder on ring increment.

	 */

	int is_pow2;

	unsigned int entries;

	unsigned int queued;

	unsigned int head;

	unsigned int tail;

};

struct libaio_options {

	void *pad;

	unsigned int userspace_reap;

	unsigned int cmdprio_percentage;

};

static struct fio_option options[] = {

	{

		.name	= "userspace_reap",

		.lname	= "Libaio userspace reaping",

		.type	= FIO_OPT_STR_SET,

		.off1	= offsetof(struct libaio_options, userspace_reap),

		.help	= "Use alternative user-space reap implementation",

		.category = FIO_OPT_C_ENGINE,

		.group	= FIO_OPT_G_LIBAIO,

	},

#ifdef FIO_HAVE_IOPRIO_CLASS

	{

		.name	= "cmdprio_percentage",

		.lname	= "high priority percentage",

		.type	= FIO_OPT_INT,

		.off1	= offsetof(struct libaio_options, cmdprio_percentage),

		.minval	= 1,

		.maxval	= 100,

		.help	= "Send high priority I/O this percentage of the time",

		.category = FIO_OPT_C_ENGINE,

		.group	= FIO_OPT_G_LIBAIO,

	},

#else

	{

		.name	= "cmdprio_percentage",

		.lname	= "high priority percentage",

		.type	= FIO_OPT_UNSUPPORTED,

		.help	= "Your platform does not support I/O priority classes",

	},

#endif

	{

		.name	= NULL,

	},

};

static inline void ring_inc(struct libaio_data *ld, unsigned int *val,

			    unsigned int add)

{

	if (ld->is_pow2)

		*val = (*val + add) & (ld->entries - 1);

	else

		*val = (*val + add) % ld->entries;

}

static int fio_libaio_prep(struct thread_data fio_unused *td, struct io_u *io_u)

{

	struct fio_file *f = io_u->file;

	struct iocb *iocb = &io_u->iocb;

	if (io_u->ddir == DDIR_READ) {

		io_prep_pread(iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);

	} else if (io_u->ddir == DDIR_WRITE) {

		io_prep_pwrite(iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);

	} else if (ddir_sync(io_u->ddir))

		io_prep_fsync(iocb, f->fd);

	return 0;

}

static void fio_libaio_prio_prep(struct thread_data *td, struct io_u *io_u)

{

	struct libaio_options *o = td->eo;

	if (rand_between(&td->prio_state, 0, 99) < o->cmdprio_percentage) {

		io_u->iocb.aio_reqprio = IOPRIO_CLASS_RT << IOPRIO_CLASS_SHIFT;

		io_u->iocb.u.c.flags |= IOCB_FLAG_IOPRIO;

		io_u->flags |= IO_U_F_PRIORITY;

	}

	return;

}

static struct io_u *fio_libaio_event(struct thread_data *td, int event)

{

	struct libaio_data *ld = td->io_ops_data;

	struct io_event *ev;

	struct io_u *io_u;

	ev = ld->aio_events + event;

	io_u = container_of(ev->obj, struct io_u, iocb);

	if (ev->res != io_u->xfer_buflen) {

		if (ev->res > io_u->xfer_buflen)

			io_u->error = -ev->res;

		else

			io_u->resid = io_u->xfer_buflen - ev->res;

	} else

		io_u->error = 0;

	return io_u;

}

struct aio_ring {

	unsigned id;		 /** kernel internal index number */

	unsigned nr;		 /** number of io_events */

	unsigned head;

	unsigned tail;

	unsigned magic;

	unsigned compat_features;

	unsigned incompat_features;

	unsigned header_length;	/** size of aio_ring */

	struct io_event events[0];

};

#define AIO_RING_MAGIC	0xa10a10a1

static int user_io_getevents(io_context_t aio_ctx, unsigned int max,

			     struct io_event *events)

{

	long i = 0;

	unsigned head;

	struct aio_ring *ring = (struct aio_ring*) aio_ctx;

	while (i < max) {

		head = ring->head;

		if (head == ring->tail) {

			/* There are no more completions */

			break;

		} else {

			/* There is another completion to reap */

			events[i] = ring->events[head];

			read_barrier();

			ring->head = (head + 1) % ring->nr;

			i++;

		}

	}

	return i;

}

static int fio_libaio_getevents(struct thread_data *td, unsigned int min,

				unsigned int max, const struct timespec *t)

{

	struct libaio_data *ld = td->io_ops_data;

	struct libaio_options *o = td->eo;

	unsigned actual_min = td->o.iodepth_batch_complete_min == 0 ? 0 : min;

	struct timespec __lt, *lt = NULL;

	int r, events = 0;

	if (t) {

		__lt = *t;

		lt = &__lt;

	}

	do {

		if (o->userspace_reap == 1

		    && actual_min == 0

		    && ((struct aio_ring *)(ld->aio_ctx))->magic

				== AIO_RING_MAGIC) {

			r = user_io_getevents(ld->aio_ctx, max,

				ld->aio_events + events);

		} else {

			r = io_getevents(ld->aio_ctx, actual_min,

				max, ld->aio_events + events, lt);

		}

		if (r > 0)

			events += r;

		else if ((min && r == 0) || r == -EAGAIN) {

			fio_libaio_commit(td);

			if (actual_min)

				usleep(10);

		} else if (r != -EINTR)

			break;

	} while (events < min);

	return r < 0 ? r : events;

}

static enum fio_q_status fio_libaio_queue(struct thread_data *td,

					  struct io_u *io_u)

{

	struct libaio_data *ld = td->io_ops_data;

	struct libaio_options *o = td->eo;

	fio_ro_check(td, io_u);

	if (ld->queued == td->o.iodepth)

		return FIO_Q_BUSY;

	/*

	 * fsync is tricky, since it can fail and we need to do it

	 * serialized with other io. the reason is that linux doesn't

	 * support aio fsync yet. So return busy for the case where we

	 * have pending io, to let fio complete those first.

	 */

	if (ddir_sync(io_u->ddir)) {

		if (ld->queued)

			return FIO_Q_BUSY;

		do_io_u_sync(td, io_u);

		return FIO_Q_COMPLETED;

	}

	if (io_u->ddir == DDIR_TRIM) {

		if (ld->queued)

			return FIO_Q_BUSY;

		do_io_u_trim(td, io_u);

		io_u_mark_submit(td, 1);

		io_u_mark_complete(td, 1);

		return FIO_Q_COMPLETED;

	}

	if (o->cmdprio_percentage)

		fio_libaio_prio_prep(td, io_u);

	ld->iocbs[ld->head] = &io_u->iocb;

	ld->io_us[ld->head] = io_u;

	ring_inc(ld, &ld->head, 1);

	ld->queued++;

	return FIO_Q_QUEUED;

}

static void fio_libaio_queued(struct thread_data *td, struct io_u **io_us,

			      unsigned int nr)

{

	struct timespec now;

	unsigned int i;

	if (!fio_fill_issue_time(td))

		return;

	fio_gettime(&now, NULL);

	for (i = 0; i < nr; i++) {

		struct io_u *io_u = io_us[i];

		memcpy(&io_u->issue_time, &now, sizeof(now));

		io_u_queued(td, io_u);

	}

}

static int fio_libaio_commit(struct thread_data *td)

{

	struct libaio_data *ld = td->io_ops_data;

	struct iocb **iocbs;

	struct io_u **io_us;

	struct timespec ts;

	int ret, wait_start = 0;

	if (!ld->queued)

		return 0;

	do {

		long nr = ld->queued;

		nr = min((unsigned int) nr, ld->entries - ld->tail);

		io_us = ld->io_us + ld->tail;

		iocbs = ld->iocbs + ld->tail;

		ret = io_submit(ld->aio_ctx, nr, iocbs);

		if (ret > 0) {

			fio_libaio_queued(td, io_us, ret);

			io_u_mark_submit(td, ret);

			ld->queued -= ret;

			ring_inc(ld, &ld->tail, ret);

			ret = 0;

			wait_start = 0;

		} else if (ret == -EINTR || !ret) {

			if (!ret)

				io_u_mark_submit(td, ret);

			wait_start = 0;

			continue;

		} else if (ret == -EAGAIN) {

			/*

			 * If we get EAGAIN, we should break out without

			 * error and let the upper layer reap some

			 * events for us. If we have no queued IO, we

			 * must loop here. If we loop for more than 30s,

			 * just error out, something must be buggy in the

			 * IO path.

			 */

			if (ld->queued) {

				ret = 0;

				break;

			}

			if (!wait_start) {

				fio_gettime(&ts, NULL);

				wait_start = 1;

			} else if (mtime_since_now(&ts) > 30000) {

				log_err("fio: aio appears to be stalled, giving up\n");

				break;

			}

			usleep(1);

			continue;

		} else if (ret == -ENOMEM) {

			/*

			 * If we get -ENOMEM, reap events if we can. If

			 * we cannot, treat it as a fatal event since there's

			 * nothing we can do about it.

			 */

			if (ld->queued)

				ret = 0;

			break;

		} else

			break;

	} while (ld->queued);

	return ret;

}

static int fio_libaio_cancel(struct thread_data *td, struct io_u *io_u)

{

	struct libaio_data *ld = td->io_ops_data;

	return io_cancel(ld->aio_ctx, &io_u->iocb, ld->aio_events);

}

static void fio_libaio_cleanup(struct thread_data *td)

{

	struct libaio_data *ld = td->io_ops_data;

	if (ld) {

		/*

		 * Work-around to avoid huge RCU stalls at exit time. If we

		 * don't do this here, then it'll be torn down by exit_aio().

		 * But for that case we can parallellize the freeing, thus

		 * speeding it up a lot.

		 */

		if (!(td->flags & TD_F_CHILD))

			io_destroy(ld->aio_ctx);

		free(ld->aio_events);

		free(ld->iocbs);

		free(ld->io_us);

		free(ld);

	}

}

static int fio_libaio_post_init(struct thread_data *td)

{

	struct libaio_data *ld = td->io_ops_data;

	int err;

	err = io_queue_init(td->o.iodepth, &ld->aio_ctx);

	if (err) {

		td_verror(td, -err, "io_queue_init");

		return 1;

	}

	return 0;

}

static int fio_libaio_init(struct thread_data *td)

{

	struct libaio_data *ld;

	struct thread_options *to = &td->o;

	struct libaio_options *o = td->eo;

	ld = calloc(1, sizeof(*ld));

	ld->entries = td->o.iodepth;

	ld->is_pow2 = is_power_of_2(ld->entries);

	ld->aio_events = calloc(ld->entries, sizeof(struct io_event));

	ld->iocbs = calloc(ld->entries, sizeof(struct iocb *));

	ld->io_us = calloc(ld->entries, sizeof(struct io_u *));

	td->io_ops_data = ld;

	/*

	 * Check for option conflicts

	 */

	if ((fio_option_is_set(to, ioprio) || fio_option_is_set(to, ioprio_class)) &&

			o->cmdprio_percentage != 0) {

		log_err("%s: cmdprio_percentage option and mutually exclusive "

				"prio or prioclass option is set, exiting\n", to->name);

		td_verror(td, EINVAL, "fio_libaio_init");

		return 1;

	}

	return 0;

}

static struct ioengine_ops ioengine = {

	.name			= "libaio",

	.version		= FIO_IOOPS_VERSION,

	.flags			= FIO_ASYNCIO_SYNC_TRIM,

	.init			= fio_libaio_init,

	.post_init		= fio_libaio_post_init,

	.prep			= fio_libaio_prep,

	.queue			= fio_libaio_queue,

	.commit			= fio_libaio_commit,

	.cancel			= fio_libaio_cancel,

	.getevents		= fio_libaio_getevents,

	.event			= fio_libaio_event,

	.cleanup		= fio_libaio_cleanup,

	.open_file		= generic_open_file,

	.close_file		= generic_close_file,

	.get_file_size		= generic_get_file_size,

	.options		= options,

	.option_struct_size	= sizeof(struct libaio_options),

};

static void fio_init fio_libaio_register(void)

{

	register_ioengine(&ioengine);

}

static void fio_exit fio_libaio_unregister(void)

{

	unregister_ioengine(&ioengine);

}