/*
 * linux/kernel/time/tick-oneshot.c
 *
 * This file contains functions which manage high resolution tick
 * related events.
 *
 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
 *
 * This code is licenced under the GPL version 2. For details see
 * kernel-base/COPYING.
 */
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/hrtimer.h>
#include <linux/interrupt.h>
#include <linux/percpu.h>
#include <linux/profile.h>
#include <linux/sched.h>

#include "tick-internal.h"

/**
 * tick_program_event
 */
int tick_program_event(ktime_t expires, int force)
{
	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);

	if (unlikely(expires == KTIME_MAX)) {
		/*
		 * We don't need the clock event device any more, stop it.
		 */
		clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT_STOPPED);
		return 0;
	}

	if (unlikely(clockevent_state_oneshot_stopped(dev))) {
		/*
		 * We need the clock event again, configure it in ONESHOT mode
		 * before using it.
		 */
		clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
	}

	return clockevents_program_event(dev, expires, force);
}

/**
 * tick_resume_onshot - resume oneshot mode
 */
void tick_resume_oneshot(void)
{
	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);

	clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
	clockevents_program_event(dev, ktime_get(), true);
}

/**
 * tick_setup_oneshot - setup the event device for oneshot mode (hres or nohz)
 */
void tick_setup_oneshot(struct clock_event_device *newdev,
			void (*handler)(struct clock_event_device *),
			ktime_t next_event)
{
	newdev->event_handler = handler;
	clockevents_switch_state(newdev, CLOCK_EVT_STATE_ONESHOT);
	clockevents_program_event(newdev, next_event, true);
}

/**
 * tick_switch_to_oneshot - switch to oneshot mode
 */
int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *))
{
	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
	struct clock_event_device *dev = td->evtdev;

	if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) ||
		    !tick_device_is_functional(dev)) {

		printk(KERN_INFO "Clockevents: "
		       "could not switch to one-shot mode:");
		if (!dev) {
			printk(" no tick device\n");
		} else {
			if (!tick_device_is_functional(dev))
				printk(" %s is not functional.\n", dev->name);
			else
				printk(" %s does not support one-shot mode.\n",
				       dev->name);
		}
		return -EINVAL;
	}

	td->mode = TICKDEV_MODE_ONESHOT;
	dev->event_handler = handler;
	clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
	tick_broadcast_switch_to_oneshot();
	return 0;
}

/**
 * tick_check_oneshot_mode - check whether the system is in oneshot mode
 *
 * returns 1 when either nohz or highres are enabled. otherwise 0.
 */
int tick_oneshot_mode_active(void)
{
	unsigned long flags;
	int ret;

	local_irq_save(flags);
	ret = __this_cpu_read(tick_cpu_device.mode) == TICKDEV_MODE_ONESHOT;
	local_irq_restore(flags);

	return ret;
}

#ifdef CONFIG_HIGH_RES_TIMERS
/**
 * tick_init_highres - switch to high resolution mode
 *
 * Called with interrupts disabled.
 */
int tick_init_highres(void)
{
	return tick_switch_to_oneshot(hrtimer_interrupt);
}
#endif
cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='eeeefd41843218c55a8782a6920f044d9bf6207a'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Christoph Hellwig &lt;hch@lst.de&gt;</td><td class='right'>2017-02-05 18:10:35 +0100</td></tr>
<tr><th>committer</th><td>Jens Axboe &lt;axboe@fb.com&gt;</td><td class='right'>2017-02-06 09:34:46 -0700</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/uapi/mtd/mtd-abi.h?id=eeeefd41843218c55a8782a6920f044d9bf6207a'>eeeefd41843218c55a8782a6920f044d9bf6207a</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/uapi/mtd/mtd-abi.h?id=eeeefd41843218c55a8782a6920f044d9bf6207a'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=eeeefd41843218c55a8782a6920f044d9bf6207a'>c342eac46626e62745aa8e1a982626efca8b121d</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/uapi/mtd/mtd-abi.h?id=eeeefd41843218c55a8782a6920f044d9bf6207a'>include/uapi/mtd/mtd-abi.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/uapi/mtd/mtd-abi.h?id=c14024dbb156c8392908aaa822097d27c6af8ec8'>c14024dbb156c8392908aaa822097d27c6af8ec8</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/uapi/mtd/mtd-abi.h?id=eeeefd41843218c55a8782a6920f044d9bf6207a&amp;id2=c14024dbb156c8392908aaa822097d27c6af8ec8'>diff</a>)</td></tr></table>
<div class='commit-subject'>block: don't try Write Same from __blkdev_issue_zeroout</div><div class='commit-msg'>Write Same can return an error asynchronously if it turns out the
underlying SCSI device does not support Write Same, which makes a
proper fallback to other methods in __blkdev_issue_zeroout impossible.
Thus only issue a Write Same from blkdev_issue_zeroout an don't try it
at all from __blkdev_issue_zeroout as a non-invasive workaround.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reported-by: Junichi Nomura &lt;j-nomura@ce.jp.nec.com&gt;
Fixes: e73c23ff ("block: add async variant of blkdev_issue_zeroout")
Tested-by: Junichi Nomura &lt;j-nomura@ce.jp.nec.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@fb.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=eeeefd41843218c55a8782a6920f044d9bf6207a'>Diffstat</a> (limited to 'include/uapi/mtd/mtd-abi.h')</div><table summary='diffstat' class='diffstat'>