Revision 88fa025d30ea97a2aae6394794bdfc31dc9423b7 authored by Linus Torvalds on 31 December 2017, 19:23:11 UTC, committed by Linus Torvalds on 31 December 2017, 19:23:11 UTC
Pull irq fixes from Thomas Gleixner: "A rather large update after the kaisered maintainer finally found time to handle regression reports. - The larger part addresses a regression caused by the x86 vector management rework. The reservation based model does not work reliably for MSI interrupts, if they cannot be masked (yes, yet another hw engineering trainwreck). The reason is that the reservation mode assigns a dummy vector when the interrupt is allocated and switches to a real vector when the interrupt is requested. If the MSI entry cannot be masked then the initialization might raise an interrupt before the interrupt is requested, which ends up as spurious interrupt and causes device malfunction and worse. The fix is to exclude MSI interrupts which do not support masking from reservation mode and assign a real vector right away. - Extend the extra lockdep class setup for nested interrupts with a class for the recently added irq_desc::request_mutex so lockdep can differeniate and does not emit false positive warnings. - A ratelimit guard for the bad irq printout so in case a bad irq comes back immediately the system does not drown in dmesg spam" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq/msi, x86/vector: Prevent reservation mode for non maskable MSI genirq/irqdomain: Rename early argument of irq_domain_activate_irq() x86/vector: Use IRQD_CAN_RESERVE flag genirq: Introduce IRQD_CAN_RESERVE flag genirq/msi: Handle reactivation only on success gpio: brcmstb: Make really use of the new lockdep class genirq: Guard handle_bad_irq log messages kernel/irq: Extend lockdep class for request mutex
user-return-notifier.c
#include <linux/user-return-notifier.h>
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/export.h>
static DEFINE_PER_CPU(struct hlist_head, return_notifier_list);
/*
* Request a notification when the current cpu returns to userspace. Must be
* called in atomic context. The notifier will also be called in atomic
* context.
*/
void user_return_notifier_register(struct user_return_notifier *urn)
{
set_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
hlist_add_head(&urn->link, this_cpu_ptr(&return_notifier_list));
}
EXPORT_SYMBOL_GPL(user_return_notifier_register);
/*
* Removes a registered user return notifier. Must be called from atomic
* context, and from the same cpu registration occurred in.
*/
void user_return_notifier_unregister(struct user_return_notifier *urn)
{
hlist_del(&urn->link);
if (hlist_empty(this_cpu_ptr(&return_notifier_list)))
clear_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
}
EXPORT_SYMBOL_GPL(user_return_notifier_unregister);
/* Calls registered user return notifiers */
void fire_user_return_notifiers(void)
{
struct user_return_notifier *urn;
struct hlist_node *tmp2;
struct hlist_head *head;
head = &get_cpu_var(return_notifier_list);
hlist_for_each_entry_safe(urn, tmp2, head, link)
urn->on_user_return(urn);
put_cpu_var(return_notifier_list);
}
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