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Revision a7ca10f263d7e673c74d8e0946d6b9993405cc9c authored by Linus Torvalds on 29 October 2014, 23:38:48 UTC, committed by Linus Torvalds on 29 October 2014, 23:38:48 UTC 
Merge branch 'akpm' (incoming from Andrew Morton)
 
Merge misc fixes from Andrew Morton:
 "21 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (21 commits)
  mm/balloon_compaction: fix deflation when compaction is disabled
  sh: fix sh770x SCIF memory regions
  zram: avoid NULL pointer access in concurrent situation
  mm/slab_common: don't check for duplicate cache names
  ocfs2: fix d_splice_alias() return code checking
  mm: rmap: split out page_remove_file_rmap()
  mm: memcontrol: fix missed end-writeback page accounting
  mm: page-writeback: inline account_page_dirtied() into single caller
  lib/bitmap.c: fix undefined shift in __bitmap_shift_{left|right}()
  drivers/rtc/rtc-bq32k.c: fix register value
  memory-hotplug: clear pgdat which is allocated by bootmem in try_offline_node()
  drivers/rtc/rtc-s3c.c: fix initialization failure without rtc source clock
  kernel/kmod: fix use-after-free of the sub_info structure
  drivers/rtc/rtc-pm8xxx.c: rework to support pm8941 rtc
  mm, thp: fix collapsing of hugepages on madvise
  drivers: of: add return value to of_reserved_mem_device_init()
  mm: free compound page with correct order
  gcov: add ARM64 to GCOV_PROFILE_ALL
  fsnotify: next_i is freed during fsnotify_unmount_inodes.
  mm/compaction.c: avoid premature range skip in isolate_migratepages_range
  ...
2 parent s d506aa6 + 4d88e6f
Raw File
fs_pin.c 
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/fs_pin.h>
#include "internal.h"
#include "mount.h"

static void pin_free_rcu(struct rcu_head *head)
{
	kfree(container_of(head, struct fs_pin, rcu));
}

static DEFINE_SPINLOCK(pin_lock);

void pin_put(struct fs_pin *p)
{
	if (atomic_long_dec_and_test(&p->count))
		call_rcu(&p->rcu, pin_free_rcu);
}

void pin_remove(struct fs_pin *pin)
{
	spin_lock(&pin_lock);
	hlist_del(&pin->m_list);
	hlist_del(&pin->s_list);
	spin_unlock(&pin_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 mnt_pin_kill(struct mount *m)
{
	while (1) {
		struct hlist_node *p;
		struct fs_pin *pin;
		rcu_read_lock();
		p = ACCESS_ONCE(m->mnt_pins.first);
		if (!p) {
			rcu_read_unlock();
			break;
		}
		pin = hlist_entry(p, struct fs_pin, m_list);
		if (!atomic_long_inc_not_zero(&pin->count)) {
			rcu_read_unlock();
			cpu_relax();
			continue;
		}
		rcu_read_unlock();
		pin->kill(pin);
	}
}

void sb_pin_kill(struct super_block *sb)
{
	while (1) {
		struct hlist_node *p;
		struct fs_pin *pin;
		rcu_read_lock();
		p = ACCESS_ONCE(sb->s_pins.first);
		if (!p) {
			rcu_read_unlock();
			break;
		}
		pin = hlist_entry(p, struct fs_pin, s_list);
		if (!atomic_long_inc_not_zero(&pin->count)) {
			rcu_read_unlock();
			cpu_relax();
			continue;
		}
		rcu_read_unlock();
		pin->kill(pin);
	}
}
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