Revision df43d903828c59afb9e93b59835127a02e1f8144 authored by Linus Torvalds on 02 September 2021, 01:41:13 UTC, committed by Linus Torvalds on 02 September 2021, 01:41:13 UTC
Pull printk updates from Petr Mladek: - Optionally, provide an index of possible printk messages via <debugfs>/printk/index/. It can be used when monitoring important kernel messages on a farm of various hosts. The monitor has to be updated when some messages has changed or are not longer available by a newly deployed kernel. - Add printk.console_no_auto_verbose boot parameter. It allows to generate crash dump even with slow consoles in a reasonable time frame. - Remove printk_safe buffers. The messages are always stored directly to the main logbuffer, even in NMI or recursive context. Also it allows to serialize syslog operations by a mutex instead of a spin lock. - Misc clean up and build fixes. * tag 'printk-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: printk/index: Fix -Wunused-function warning lib/nmi_backtrace: Serialize even messages about idle CPUs printk: Add printk.console_no_auto_verbose boot parameter printk: Remove console_silent() lib/test_scanf: Handle n_bits == 0 in random tests printk: syslog: close window between wait and read printk: convert @syslog_lock to mutex printk: remove NMI tracking printk: remove safe buffers printk: track/limit recursion lib/nmi_backtrace: explicitly serialize banner and regs printk: Move the printk() kerneldoc comment to its new home printk/index: Fix warning about missing prototypes MIPS/asm/printk: Fix build failure caused by printk printk: index: Add indexing support to dev_printk printk: Userspace format indexing support printk: Rework parse_prefix into printk_parse_prefix printk: Straighten out log_flags into printk_info_flags string_helpers: Escape double quotes in escape_special printk/console: Check consistent sequence number when handling race in console_unlock()
fs_pin.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "internal.h"
#include "mount.h"
static DEFINE_SPINLOCK(pin_lock);
void pin_remove(struct fs_pin *pin)
{
spin_lock(&pin_lock);
hlist_del_init(&pin->m_list);
hlist_del_init(&pin->s_list);
spin_unlock(&pin_lock);
spin_lock_irq(&pin->wait.lock);
pin->done = 1;
wake_up_locked(&pin->wait);
spin_unlock_irq(&pin->wait.lock);
}
void pin_insert(struct fs_pin *pin, struct vfsmount *m)
{
spin_lock(&pin_lock);
hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins);
hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
spin_unlock(&pin_lock);
}
void pin_kill(struct fs_pin *p)
{
wait_queue_entry_t wait;
if (!p) {
rcu_read_unlock();
return;
}
init_wait(&wait);
spin_lock_irq(&p->wait.lock);
if (likely(!p->done)) {
p->done = -1;
spin_unlock_irq(&p->wait.lock);
rcu_read_unlock();
p->kill(p);
return;
}
if (p->done > 0) {
spin_unlock_irq(&p->wait.lock);
rcu_read_unlock();
return;
}
__add_wait_queue(&p->wait, &wait);
while (1) {
set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock_irq(&p->wait.lock);
rcu_read_unlock();
schedule();
rcu_read_lock();
if (likely(list_empty(&wait.entry)))
break;
/* OK, we know p couldn't have been freed yet */
spin_lock_irq(&p->wait.lock);
if (p->done > 0) {
spin_unlock_irq(&p->wait.lock);
break;
}
}
rcu_read_unlock();
}
void mnt_pin_kill(struct mount *m)
{
while (1) {
struct hlist_node *p;
rcu_read_lock();
p = READ_ONCE(m->mnt_pins.first);
if (!p) {
rcu_read_unlock();
break;
}
pin_kill(hlist_entry(p, struct fs_pin, m_list));
}
}
void group_pin_kill(struct hlist_head *p)
{
while (1) {
struct hlist_node *q;
rcu_read_lock();
q = READ_ONCE(p->first);
if (!q) {
rcu_read_unlock();
break;
}
pin_kill(hlist_entry(q, struct fs_pin, s_list));
}
}
Computing file changes ...