flex_array: add flex_array_clear function

[linux-2.6.git] / lib / flex_array.c

diff --git a/lib/flex_array.c b/lib/flex_array.c
index e73c691..b68f99b 100644 (file)
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -99,7 +99,8 @@ static inline int elements_fit_in_base(struct flex_array *fa)
  * capacity in the base structure.  Also note that no effort is made
  * to efficiently pack objects across page boundaries.
  */
-struct flex_array *flex_array_alloc(int element_size, int total, gfp_t flags)
+struct flex_array *flex_array_alloc(int element_size, unsigned int total,
+                                       gfp_t flags)
 {
        struct flex_array *ret;
        int max_size = nr_base_part_ptrs() * __elements_per_part(element_size);
@@ -115,16 +116,14 @@ struct flex_array *flex_array_alloc(int element_size, int total, gfp_t flags)
        return ret;
 }
 
-static int fa_element_to_part_nr(struct flex_array *fa, int element_nr)
+static int fa_element_to_part_nr(struct flex_array *fa,
+                                       unsigned int element_nr)
 {
        return element_nr / __elements_per_part(fa->element_size);
 }
 
 /**
  * flex_array_free_parts - just free the second-level pages
- * @src:       address of data to copy into the array
- * @element_nr:        index of the position in which to insert
- *             the new element.
  *
  * This is to be used in cases where the base 'struct flex_array'
  * has been statically allocated and should not be free.
@@ -146,14 +145,12 @@ void flex_array_free(struct flex_array *fa)
        kfree(fa);
 }
 
-static int fa_index_inside_part(struct flex_array *fa, int element_nr)
+static unsigned int index_inside_part(struct flex_array *fa,
+                                       unsigned int element_nr)
 {
-       return element_nr % __elements_per_part(fa->element_size);
-}
+       unsigned int part_offset;
 
-static int index_inside_part(struct flex_array *fa, int element_nr)
-{
-       int part_offset = fa_index_inside_part(fa, element_nr);
+       part_offset = element_nr % __elements_per_part(fa->element_size);
        return part_offset * fa->element_size;
 }
 
@@ -188,7 +185,8 @@ __fa_get_part(struct flex_array *fa, int part_nr, gfp_t flags)
  *
  * Locking must be provided by the caller.
  */
-int flex_array_put(struct flex_array *fa, int element_nr, void *src, gfp_t flags)
+int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
+                       gfp_t flags)
 {
        int part_nr = fa_element_to_part_nr(fa, element_nr);
        struct flex_array_part *part;
@@ -209,6 +207,32 @@ int flex_array_put(struct flex_array *fa, int element_nr, void *src, gfp_t flags
 }
 
 /**
+ * flex_array_clear - clear element in array at @element_nr
+ * @element_nr:        index of the position to clear.
+ *
+ * Locking must be provided by the caller.
+ */
+int flex_array_clear(struct flex_array *fa, unsigned int element_nr)
+{
+       int part_nr = fa_element_to_part_nr(fa, element_nr);
+       struct flex_array_part *part;
+       void *dst;
+
+       if (element_nr >= fa->total_nr_elements)
+               return -ENOSPC;
+       if (elements_fit_in_base(fa))
+               part = (struct flex_array_part *)&fa->parts[0];
+       else {
+               part = fa->parts[part_nr];
+               if (!part)
+                       return -EINVAL;
+       }
+       dst = &part->elements[index_inside_part(fa, element_nr)];
+       memset(dst, 0, fa->element_size);
+       return 0;
+}
+
+/**
  * flex_array_prealloc - guarantee that array space exists
  * @start:     index of first array element for which space is allocated
  * @end:       index of last (inclusive) element for which space is allocated
@@ -220,7 +244,8 @@ int flex_array_put(struct flex_array *fa, int element_nr, void *src, gfp_t flags
  *
  * Locking must be provided by the caller.
  */
-int flex_array_prealloc(struct flex_array *fa, int start, int end, gfp_t flags)
+int flex_array_prealloc(struct flex_array *fa, unsigned int start,
+                       unsigned int end, gfp_t flags)
 {
        int start_part;
        int end_part;
@@ -251,7 +276,7 @@ int flex_array_prealloc(struct flex_array *fa, int start, int end, gfp_t flags)
  *
  * Locking must be provided by the caller.
  */
-void *flex_array_get(struct flex_array *fa, int element_nr)
+void *flex_array_get(struct flex_array *fa, unsigned int element_nr)
 {
        int part_nr = fa_element_to_part_nr(fa, element_nr);
        struct flex_array_part *part;