Find next nearest power of 2 in fr_ring_buffer_create

diff --git a/src/lib/io/ring_buffer.c b/src/lib/io/ring_buffer.c
index e3d9247c32d966b03bb0b60b4b1dbb2163e7e5e0..43af4ea9c92ead76aa6163cb2baec266bc82a239 100644 (file)
--- a/src/lib/io/ring_buffer.c
+++ b/src/lib/io/ring_buffer.c
@@ -45,23 +45,26 @@ struct fr_ring_buffer_t {
        bool            closed;         //!< whether allocations are closed
 };
 
-
 /** Create a ring buffer.
  *
- *  The ring buffer should be a power of two in size.
+ *  The size provided will be rounded up to the next highest power of
+ *  2, if it's not already a power of 2.
  *
  *  The ring buffer manages how much room is reserved (i.e. available
  *  to write to), and used.  The application is responsible for
  *  tracking the start of the reservation, *and* it's write offset
  *  within that reservation.
  *
- * @param[in] ctx a talloc context
- * @param[in] size of the raw ring buffer array to allocate.
- * @return a ring buffer, or NULL on failure.
+ * @param[in] ctx      a talloc context
+ * @param[in] size     of the raw ring buffer array to allocate.
+ * @return
+ *     - A new ring buffer on success.
+ *     - NULL on failure.
  */
 fr_ring_buffer_t *fr_ring_buffer_create(TALLOC_CTX *ctx, size_t size)
 {
-       fr_ring_buffer_t *rb;
+       fr_ring_buffer_t        *rb;
+       size_t                  pow;
 
        rb = talloc_zero(ctx, fr_ring_buffer_t);
        if (!rb) {
@@ -70,13 +73,22 @@ fr_ring_buffer_t *fr_ring_buffer_create(TALLOC_CTX *ctx, size_t size)
                return NULL;
        }
 
+       /*
+        *      Find the nearest power of 2 (rounding up)
+        */
+       for (pow = 0x00000001;
+            pow < size;
+            pow <<= 1);
+       size = pow;
+       size--;
+
        rb->buffer = talloc_array(rb, uint8_t, size);
        if (!rb->buffer) {
                talloc_free(rb);
                goto fail;
        }
-
        rb->size = size;
+
        return rb;
 }