Revision 2b369478e1856e3809f439495567474725931585 authored by Linus Torvalds on 09 February 2017, 20:25:42 UTC, committed by Linus Torvalds on 09 February 2017, 20:25:42 UTC
Pull pstore fix from Kees Cook: "Fix pstore regression (boot Oops) when ftrace disabled, from Brian Norris" * tag 'pstore-v4.10-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: pstore: don't OOPS when there are no ftrace zones
dec_and_lock.c
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
/*
* This is an implementation of the notion of "decrement a
* reference count, and return locked if it decremented to zero".
*
* NOTE NOTE NOTE! This is _not_ equivalent to
*
* if (atomic_dec_and_test(&atomic)) {
* spin_lock(&lock);
* return 1;
* }
* return 0;
*
* because the spin-lock and the decrement must be
* "atomic".
*/
int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
{
/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
if (atomic_add_unless(atomic, -1, 1))
return 0;
/* Otherwise do it the slow way */
spin_lock(lock);
if (atomic_dec_and_test(atomic))
return 1;
spin_unlock(lock);
return 0;
}
EXPORT_SYMBOL(_atomic_dec_and_lock);
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...