iov_iter: Define flags to qualify page extraction.

[platform/kernel/linux-rpi.git] / lib / dec_and_lock.c

diff --git a/lib/dec_and_lock.c b/lib/dec_and_lock.c
index 9555b68..1dcca8f 100644 (file)
--- a/lib/dec_and_lock.c
+++ b/lib/dec_and_lock.c
@@ -49,3 +49,34 @@ int _atomic_dec_and_lock_irqsave(atomic_t *atomic, spinlock_t *lock,
        return 0;
 }
 EXPORT_SYMBOL(_atomic_dec_and_lock_irqsave);
+
+int _atomic_dec_and_raw_lock(atomic_t *atomic, raw_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 */
+       raw_spin_lock(lock);
+       if (atomic_dec_and_test(atomic))
+               return 1;
+       raw_spin_unlock(lock);
+       return 0;
+}
+EXPORT_SYMBOL(_atomic_dec_and_raw_lock);
+
+int _atomic_dec_and_raw_lock_irqsave(atomic_t *atomic, raw_spinlock_t *lock,
+                                    unsigned long *flags)
+{
+       /* 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 */
+       raw_spin_lock_irqsave(lock, *flags);
+       if (atomic_dec_and_test(atomic))
+               return 1;
+       raw_spin_unlock_irqrestore(lock, *flags);
+       return 0;
+}
+EXPORT_SYMBOL(_atomic_dec_and_raw_lock_irqsave);