percpu_ref: add PERCPU_REF_INIT_* flags

[sfrench/cifs-2.6.git] / lib / percpu-refcount.c

diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index 5a6d43baccc52782ca50436113d075ada9a08f84..ed280fb1e5b578fe96f0299fff2c6d44a78ce7ff 100644 (file)
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -45,27 +45,40 @@ static unsigned long __percpu *percpu_count_ptr(struct percpu_ref *ref)
  * percpu_ref_init - initialize a percpu refcount
  * @ref: percpu_ref to initialize
  * @release: function which will be called when refcount hits 0
+ * @flags: PERCPU_REF_INIT_* flags
  * @gfp: allocation mask to use
  *
- * Initializes the refcount in single atomic counter mode with a refcount of 1;
- * analagous to atomic_long_set(ref, 1).
+ * Initializes @ref.  If @flags is zero, @ref starts in percpu mode with a
+ * refcount of 1; analagous to atomic_long_set(ref, 1).  See the
+ * definitions of PERCPU_REF_INIT_* flags for flag behaviors.
  *
  * Note that @release must not sleep - it may potentially be called from RCU
  * callback context by percpu_ref_kill().
  */
 int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release,
-                   gfp_t gfp)
+                   unsigned int flags, gfp_t gfp)
 {
        size_t align = max_t(size_t, 1 << __PERCPU_REF_FLAG_BITS,
                             __alignof__(unsigned long));
-
-       atomic_long_set(&ref->count, 1 + PERCPU_COUNT_BIAS);
+       unsigned long start_count = 0;
 
        ref->percpu_count_ptr = (unsigned long)
                __alloc_percpu_gfp(sizeof(unsigned long), align, gfp);
        if (!ref->percpu_count_ptr)
                return -ENOMEM;
 
+       if (flags & (PERCPU_REF_INIT_ATOMIC | PERCPU_REF_INIT_DEAD))
+               ref->percpu_count_ptr |= __PERCPU_REF_ATOMIC;
+       else
+               start_count += PERCPU_COUNT_BIAS;
+
+       if (flags & PERCPU_REF_INIT_DEAD)
+               ref->percpu_count_ptr |= __PERCPU_REF_DEAD;
+       else
+               start_count++;
+
+       atomic_long_set(&ref->count, start_count);
+
        ref->release = release;
        return 0;
 }