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Revision 0cdd776ec92c0fec768c7079331804d3e52d4b27 authored by Linus Torvalds on 15 May 2022, 15:08:51 UTC, committed by Linus Torvalds on 15 May 2022, 15:08:51 UTC 
Merge tag 'driver-core-5.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
 
Pull driver core fixes from Greg KH:
 "Here is one fix, and three documentation updates for 5.18-rc7.

  The fix is for the firmware loader which resolves a long-reported
  problem where the credentials of the firmware loader could be set to a
  userspace process without enough permissions to actually load the
  firmware image. Many Android vendors have been reporting this for
  quite some time.

  The documentation updates are for the embargoed-hardware-issues.rst
  file to add a new entry, change an existing one, and sort the list to
  make changes easier in the future.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-5.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  Documentation/process: Update ARM contact for embargoed hardware issues
  Documentation/process: Add embargoed HW contact for Ampere Computing
  Documentation/process: Make groups alphabetical and use tabs consistently
  firmware_loader: use kernel credentials when reading firmware
2 parent s 5becde6 + 575f00e
Raw File
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));
	}
}
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