#ifndef __ASM_PREEMPT_H
#define __ASM_PREEMPT_H

#include <linux/thread_info.h>

#define PREEMPT_ENABLED	(0)

static __always_inline int preempt_count(void)
{
	return READ_ONCE(current_thread_info()->preempt_count);
}

static __always_inline volatile int *preempt_count_ptr(void)
{
	return &current_thread_info()->preempt_count;
}

static __always_inline void preempt_count_set(int pc)
{
	*preempt_count_ptr() = pc;
}

/*
 * must be macros to avoid header recursion hell
 */
#define init_task_preempt_count(p) do { \
	task_thread_info(p)->preempt_count = FORK_PREEMPT_COUNT; \
} while (0)

#define init_idle_preempt_count(p, cpu) do { \
	task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
} while (0)

static __always_inline void set_preempt_need_resched(void)
{
}

static __always_inline void clear_preempt_need_resched(void)
{
}

static __always_inline bool test_preempt_need_resched(void)
{
	return false;
}

/*
 * The various preempt_count add/sub methods
 */

static __always_inline void __preempt_count_add(int val)
{
	*preempt_count_ptr() += val;
}

static __always_inline void __preempt_count_sub(int val)
{
	*preempt_count_ptr() -= val;
}

static __always_inline bool __preempt_count_dec_and_test(void)
{
	/*
	 * Because of load-store architectures cannot do per-cpu atomic
	 * operations; we cannot use PREEMPT_NEED_RESCHED because it might get
	 * lost.
	 */
	return !--*preempt_count_ptr() && tif_need_resched();
}

/*
 * Returns true when we need to resched and can (barring IRQ state).
 */
static __always_inline bool should_resched(int preempt_offset)
{
	return unlikely(preempt_count() == preempt_offset &&
			tif_need_resched());
}

#ifdef CONFIG_PREEMPT
extern asmlinkage void preempt_schedule(void);
#define __preempt_schedule() preempt_schedule()
extern asmlinkage void preempt_schedule_notrace(void);
#define __preempt_schedule_notrace() preempt_schedule_notrace()
#endif /* CONFIG_PREEMPT */

#endif /* __ASM_PREEMPT_H */
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=0ae8133586ad1c9be894411aaf8b17bb58c8efe5'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include?id=0ae8133586ad1c9be894411aaf8b17bb58c8efe5'>include</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='0ae8133586ad1c9be894411aaf8b17bb58c8efe5'/><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>David Ahern &lt;dsa@cumulusnetworks.com&gt;</td><td class='right'>2017-02-02 12:37:08 -0800</td></tr>
<tr><th>committer</th><td>David S. Miller &lt;davem@davemloft.net&gt;</td><td class='right'>2017-02-04 19:58:14 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include?id=0ae8133586ad1c9be894411aaf8b17bb58c8efe5'>0ae8133586ad1c9be894411aaf8b17bb58c8efe5</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include?id=0ae8133586ad1c9be894411aaf8b17bb58c8efe5'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=0ae8133586ad1c9be894411aaf8b17bb58c8efe5'>aa9c78384e5fe5b2bac9ca1895e87909bc394adf</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include?id=0ae8133586ad1c9be894411aaf8b17bb58c8efe5'>include</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include?id=4d6308aac3258ecad8444811a16951a919adc131'>4d6308aac3258ecad8444811a16951a919adc131</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include?id=0ae8133586ad1c9be894411aaf8b17bb58c8efe5&amp;id2=4d6308aac3258ecad8444811a16951a919adc131'>diff</a>)</td></tr></table>
<div class='commit-subject'>net: ipv6: Allow shorthand delete of all nexthops in multipath route</div><div class='commit-msg'>IPv4 allows multipath routes to be deleted using just the prefix and
length. For example:
    $ ip ro ls vrf red
    unreachable default metric 8192
    1.1.1.0/24
        nexthop via 10.100.1.254  dev eth1 weight 1
        nexthop via 10.11.200.2  dev eth11.200 weight 1
    10.11.200.0/24 dev eth11.200 proto kernel scope link src 10.11.200.3
    10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.3

    $ ip ro del 1.1.1.0/24 vrf red

    $ ip ro ls vrf red
    unreachable default metric 8192
    10.11.200.0/24 dev eth11.200 proto kernel scope link src 10.11.200.3
    10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.3

The same notation does not work with IPv6 because of how multipath routes
are implemented for IPv6. For IPv6 only the first nexthop of a multipath
route is deleted if the request contains only a prefix and length. This
leads to unnecessary complexity in userspace dealing with IPv6 multipath
routes.

This patch allows all nexthops to be deleted without specifying each one
in the delete request. Internally, this is done by walking the sibling
list of the route matching the specifications given (prefix, length,
metric, protocol, etc).

    $  ip -6 ro ls vrf red
    2001:db8:1::/120 dev eth1 proto kernel metric 256  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    2001:db8:200::/120 via 2001:db8:1::2 dev eth1 metric 1024  pref medium
    2001:db8:200::/120 via 2001:db8:2::2 dev eth2 metric 1024  pref medium
    ...

    $ ip -6 ro del vrf red 2001:db8:200::/120

    $ ip -6 ro ls vrf red
    2001:db8:1::/120 dev eth1 proto kernel metric 256  pref medium
    2001:db8:2::/120 dev eth2 proto kernel metric 256  pref medium
    ...

Because IPv6 allows individual nexthops to be deleted without deleting
the entire route, the ip6_route_multipath_del and non-multipath code
path (ip6_route_del) have to be discriminated so that all nexthops are
only deleted for the latter case. This is done by making the existing
fc_type in fib6_config a u16 and then adding a new u16 field with
fc_delete_all_nh as the first bit.

Suggested-by: Dinesh Dutt &lt;ddutt@cumulusnetworks.com&gt;
Signed-off-by: David Ahern &lt;dsa@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=0ae8133586ad1c9be894411aaf8b17bb58c8efe5'>Diffstat</a> (limited to 'include')</div><table summary='diffstat' class='diffstat'><tr><td class='mode'>-rw-r--r--</td><td class='upd'><a href='/cgit.cgi/linux/net-next.git/diff/include/net/ip6_fib.h?id=0ae8133586ad1c9be894411aaf8b17bb58c8efe5'>include/net/ip6_fib.h</a></td><td class='right'>4</td><td class='graph'><table summary='file diffstat' width='4%'><tr><td class='add' style='width: 75.0%;'/><td class='rem' style='width: 25.0%;'/><td class='none' style='width: 0.0%;'/></tr></table></td></tr>
</table><div class='diffstat-summary'>1 files changed, 3 insertions, 1 deletions</div><table summary='diff' class='diff'><tr><td><div class='head'>diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h