flex_array: flex_array_prealloc takes a number of elements, not an end
Change flex_array_prealloc to take the number of elements for which space
should be allocated instead of the last (inclusive) element. Users
and documentation are updated accordingly. flex_arrays got introduced before
they had users. When folks started using it, they ended up needing a
different API than was coded up originally. This swaps over to the API that
folks apparently need.
Based-on-patch-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Tested-by: Chris Richards <gizmo@giz-works.com>
Acked-by: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: stable@kernel.org [2.6.38+]
diff --git a/lib/flex_array.c b/lib/flex_array.c
index c0ea40b..0c33b24 100644
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -232,10 +232,10 @@
/**
* flex_array_prealloc - guarantee that array space exists
- * @fa: the flex array for which to preallocate parts
- * @start: index of first array element for which space is allocated
- * @end: index of last (inclusive) element for which space is allocated
- * @flags: page allocation flags
+ * @fa: the flex array for which to preallocate parts
+ * @start: index of first array element for which space is allocated
+ * @nr_elements: number of elements for which space is allocated
+ * @flags: page allocation flags
*
* This will guarantee that no future calls to flex_array_put()
* will allocate memory. It can be used if you are expecting to
@@ -245,13 +245,16 @@
* Locking must be provided by the caller.
*/
int flex_array_prealloc(struct flex_array *fa, unsigned int start,
- unsigned int end, gfp_t flags)
+ unsigned int nr_elements, gfp_t flags)
{
int start_part;
int end_part;
int part_nr;
+ unsigned int end;
struct flex_array_part *part;
+ end = start + nr_elements - 1;
+
if (start >= fa->total_nr_elements || end >= fa->total_nr_elements)
return -ENOSPC;
if (elements_fit_in_base(fa))