Use percpu_foreach_xcall() to gather volatile per-cpu counters. These
must be serialized against the interrupts / soft-interrupts in which
they're manipulated, as well as protected from non-atomic 64-bit memory
loads on 32-bit platforms.

Switch sys/net to percpu_create.

wqinput: avoid having struct wqinput_worklist directly in a percpu storage

percpu(9) has a certain memory storage for each CPU and provides it by the piece
to users. If the storages went short, percpu(9) enlarges them by allocating new
larger memory areas, replacing old ones with them and destroying the old ones.
A percpu storage referenced by a pointer gotten via percpu_getref can be
destroyed by the mechanism after a running thread sleeps even if percpu_putref
has not been called.

Input handlers of wqinput normally involves sleepable operations so we must
avoid dereferencing a percpu data (struct wqinput_worklist) after executing
an input handler. Address this situation by having just a pointer to the data
in a percpu storage instead.

Reviewed by knakahara@ and yamaguchi@

branches: 1.5.4;
Change the type of wqinput's drop counter to uint64_t. OK'd by ozaki-r@.

branches: 1.4.2; 1.4.4;
Avoid a deadlock between softnet_lock and IFNET_LOCK

A deadlock occurs because there is a violation of the rule of lock ordering;
softnet_lock is held with hodling IFNET_LOCK, which violates the rule.
To avoid the deadlock, replace softnet_lock in in_control and in6_control
with KERNEL_LOCK.

We also need to add some KERNEL_LOCKs to protect the network stack surely.
This is required, for example, for PR kern/51356.

Fix PR kern/53043

branches: 1.3.2; 1.3.8;
pool_init does not copy its name argument
therefore don't pass in a stack allocated buffer

vmstat -mv shows pool(s) with broken name(s)

use the name argument passed into wqinput_create directly
which is a static string in all 4 callee cases

(workqueue_create/workqueue_init copies the name argument)

Add missing NULL check for pool_get call with PR_NOWAIT

This should fix a kernel panic reported by wiz@ on current-users ML:
http://mail-index.netbsd.org/current-users/2017/05/03/msg031646.html

branches: 1.1.2; 1.1.4; 1.1.8;
Defer some pr_input to workqueue

pr_input is currently called in softint. Some pr_input such as ICMP, ICMPv6
and CARP can add/delete/update IP addresses and routing table entries. For
example, icmp6_redirect_input updates an a routing table entry and
nd6_ra_input may delete an IP address.

Basically such operations shouldn't be done in softint. That aside, we have
a reason to avoid the situation; psz/psref waits cannot be used in softint,
however they are required to work in such pr_input in the MP-safe world.

The change implements the workqueue pr_input framework called wqinput which
provides a means to defer pr_input of a protocol to workqueue easily.
Currently icmp_input, icmp6_input, carp_proto_input and carp6_proto_input
are deferred to workqueue by the framework.

Proposed and discussed on tech-kern and tech-net

Switch sys/net to percpu_create.

wqinput: avoid having struct wqinput_worklist directly in a percpu storage

percpu(9) has a certain memory storage for each CPU and provides it by the piece
to users. If the storages went short, percpu(9) enlarges them by allocating new
larger memory areas, replacing old ones with them and destroying the old ones.
A percpu storage referenced by a pointer gotten via percpu_getref can be
destroyed by the mechanism after a running thread sleeps even if percpu_putref
has not been called.

Input handlers of wqinput normally involves sleepable operations so we must
avoid dereferencing a percpu data (struct wqinput_worklist) after executing
an input handler. Address this situation by having just a pointer to the data
in a percpu storage instead.

Reviewed by knakahara@ and yamaguchi@

branches: 1.5.4;
Change the type of wqinput's drop counter to uint64_t. OK'd by ozaki-r@.

branches: 1.4.2; 1.4.4;
Avoid a deadlock between softnet_lock and IFNET_LOCK

A deadlock occurs because there is a violation of the rule of lock ordering;
softnet_lock is held with hodling IFNET_LOCK, which violates the rule.
To avoid the deadlock, replace softnet_lock in in_control and in6_control
with KERNEL_LOCK.

We also need to add some KERNEL_LOCKs to protect the network stack surely.
This is required, for example, for PR kern/51356.

Fix PR kern/53043

branches: 1.3.2; 1.3.8;
pool_init does not copy its name argument
therefore don't pass in a stack allocated buffer

vmstat -mv shows pool(s) with broken name(s)

use the name argument passed into wqinput_create directly
which is a static string in all 4 callee cases

(workqueue_create/workqueue_init copies the name argument)

Add missing NULL check for pool_get call with PR_NOWAIT

This should fix a kernel panic reported by wiz@ on current-users ML:
http://mail-index.netbsd.org/current-users/2017/05/03/msg031646.html

branches: 1.1.2; 1.1.4; 1.1.8;
Defer some pr_input to workqueue

pr_input is currently called in softint. Some pr_input such as ICMP, ICMPv6
and CARP can add/delete/update IP addresses and routing table entries. For
example, icmp6_redirect_input updates an a routing table entry and
nd6_ra_input may delete an IP address.

Basically such operations shouldn't be done in softint. That aside, we have
a reason to avoid the situation; psz/psref waits cannot be used in softint,
however they are required to work in such pr_input in the MP-safe world.

The change implements the workqueue pr_input framework called wqinput which
provides a means to defer pr_input of a protocol to workqueue easily.
Currently icmp_input, icmp6_input, carp_proto_input and carp6_proto_input
are deferred to workqueue by the framework.

Proposed and discussed on tech-kern and tech-net

wqinput: avoid having struct wqinput_worklist directly in a percpu storage

percpu(9) has a certain memory storage for each CPU and provides it by the piece
to users. If the storages went short, percpu(9) enlarges them by allocating new
larger memory areas, replacing old ones with them and destroying the old ones.
A percpu storage referenced by a pointer gotten via percpu_getref can be
destroyed by the mechanism after a running thread sleeps even if percpu_putref
has not been called.

Input handlers of wqinput normally involves sleepable operations so we must
avoid dereferencing a percpu data (struct wqinput_worklist) after executing
an input handler. Address this situation by having just a pointer to the data
in a percpu storage instead.

Reviewed by knakahara@ and yamaguchi@

Change the type of wqinput's drop counter to uint64_t. OK'd by ozaki-r@.

branches: 1.4.2; 1.4.4;
Avoid a deadlock between softnet_lock and IFNET_LOCK

A deadlock occurs because there is a violation of the rule of lock ordering;
softnet_lock is held with hodling IFNET_LOCK, which violates the rule.
To avoid the deadlock, replace softnet_lock in in_control and in6_control
with KERNEL_LOCK.

We also need to add some KERNEL_LOCKs to protect the network stack surely.
This is required, for example, for PR kern/51356.

Fix PR kern/53043

branches: 1.3.2; 1.3.8;
pool_init does not copy its name argument
therefore don't pass in a stack allocated buffer

vmstat -mv shows pool(s) with broken name(s)

use the name argument passed into wqinput_create directly
which is a static string in all 4 callee cases

(workqueue_create/workqueue_init copies the name argument)

Add missing NULL check for pool_get call with PR_NOWAIT

This should fix a kernel panic reported by wiz@ on current-users ML:
http://mail-index.netbsd.org/current-users/2017/05/03/msg031646.html

branches: 1.1.2; 1.1.4; 1.1.8;
Defer some pr_input to workqueue

pr_input is currently called in softint. Some pr_input such as ICMP, ICMPv6
and CARP can add/delete/update IP addresses and routing table entries. For
example, icmp6_redirect_input updates an a routing table entry and
nd6_ra_input may delete an IP address.

Basically such operations shouldn't be done in softint. That aside, we have
a reason to avoid the situation; psz/psref waits cannot be used in softint,
however they are required to work in such pr_input in the MP-safe world.

The change implements the workqueue pr_input framework called wqinput which
provides a means to defer pr_input of a protocol to workqueue easily.
Currently icmp_input, icmp6_input, carp_proto_input and carp6_proto_input
are deferred to workqueue by the framework.

Proposed and discussed on tech-kern and tech-net

Change the type of wqinput's drop counter to uint64_t. OK'd by ozaki-r@.

branches: 1.4.2;
Avoid a deadlock between softnet_lock and IFNET_LOCK

A deadlock occurs because there is a violation of the rule of lock ordering;
softnet_lock is held with hodling IFNET_LOCK, which violates the rule.
To avoid the deadlock, replace softnet_lock in in_control and in6_control
with KERNEL_LOCK.

We also need to add some KERNEL_LOCKs to protect the network stack surely.
This is required, for example, for PR kern/51356.

Fix PR kern/53043

branches: 1.3.2; 1.3.8;
pool_init does not copy its name argument
therefore don't pass in a stack allocated buffer

vmstat -mv shows pool(s) with broken name(s)

use the name argument passed into wqinput_create directly
which is a static string in all 4 callee cases

(workqueue_create/workqueue_init copies the name argument)

Add missing NULL check for pool_get call with PR_NOWAIT

This should fix a kernel panic reported by wiz@ on current-users ML:
http://mail-index.netbsd.org/current-users/2017/05/03/msg031646.html

branches: 1.1.2; 1.1.4; 1.1.8;
Defer some pr_input to workqueue

pr_input is currently called in softint. Some pr_input such as ICMP, ICMPv6
and CARP can add/delete/update IP addresses and routing table entries. For
example, icmp6_redirect_input updates an a routing table entry and
nd6_ra_input may delete an IP address.

Basically such operations shouldn't be done in softint. That aside, we have
a reason to avoid the situation; psz/psref waits cannot be used in softint,
however they are required to work in such pr_input in the MP-safe world.

The change implements the workqueue pr_input framework called wqinput which
provides a means to defer pr_input of a protocol to workqueue easily.
Currently icmp_input, icmp6_input, carp_proto_input and carp6_proto_input
are deferred to workqueue by the framework.

Proposed and discussed on tech-kern and tech-net

pool_init does not copy its name argument
therefore don't pass in a stack allocated buffer

vmstat -mv shows pool(s) with broken name(s)

use the name argument passed into wqinput_create directly
which is a static string in all 4 callee cases

(workqueue_create/workqueue_init copies the name argument)

Add missing NULL check for pool_get call with PR_NOWAIT

This should fix a kernel panic reported by wiz@ on current-users ML:
http://mail-index.netbsd.org/current-users/2017/05/03/msg031646.html

branches: 1.1.2; 1.1.4; 1.1.8;
Defer some pr_input to workqueue

pr_input is currently called in softint. Some pr_input such as ICMP, ICMPv6
and CARP can add/delete/update IP addresses and routing table entries. For
example, icmp6_redirect_input updates an a routing table entry and
nd6_ra_input may delete an IP address.

Basically such operations shouldn't be done in softint. That aside, we have
a reason to avoid the situation; psz/psref waits cannot be used in softint,
however they are required to work in such pr_input in the MP-safe world.

The change implements the workqueue pr_input framework called wqinput which
provides a means to defer pr_input of a protocol to workqueue easily.
Currently icmp_input, icmp6_input, carp_proto_input and carp6_proto_input
are deferred to workqueue by the framework.

Proposed and discussed on tech-kern and tech-net

Add missing NULL check for pool_get call with PR_NOWAIT

This should fix a kernel panic reported by wiz@ on current-users ML:
http://mail-index.netbsd.org/current-users/2017/05/03/msg031646.html

branches: 1.1.2; 1.1.4; 1.1.8;
Defer some pr_input to workqueue

pr_input is currently called in softint. Some pr_input such as ICMP, ICMPv6
and CARP can add/delete/update IP addresses and routing table entries. For
example, icmp6_redirect_input updates an a routing table entry and
nd6_ra_input may delete an IP address.

Basically such operations shouldn't be done in softint. That aside, we have
a reason to avoid the situation; psz/psref waits cannot be used in softint,
however they are required to work in such pr_input in the MP-safe world.

The change implements the workqueue pr_input framework called wqinput which
provides a means to defer pr_input of a protocol to workqueue easily.
Currently icmp_input, icmp6_input, carp_proto_input and carp6_proto_input
are deferred to workqueue by the framework.

Proposed and discussed on tech-kern and tech-net

branches: 1.1.2;
Defer some pr_input to workqueue

pr_input is currently called in softint. Some pr_input such as ICMP, ICMPv6
and CARP can add/delete/update IP addresses and routing table entries. For
example, icmp6_redirect_input updates an a routing table entry and
nd6_ra_input may delete an IP address.

Basically such operations shouldn't be done in softint. That aside, we have
a reason to avoid the situation; psz/psref waits cannot be used in softint,
however they are required to work in such pr_input in the MP-safe world.

The change implements the workqueue pr_input framework called wqinput which
provides a means to defer pr_input of a protocol to workqueue easily.
Currently icmp_input, icmp6_input, carp_proto_input and carp6_proto_input
are deferred to workqueue by the framework.

Proposed and discussed on tech-kern and tech-net