char elements[FLEX_ARRAY_PART_SIZE];
};
-static inline int __elements_per_part(int element_size)
-{
- return FLEX_ARRAY_PART_SIZE / element_size;
-}
-
-static inline int bytes_left_in_base(void)
-{
- int element_offset = offsetof(struct flex_array, parts);
- int bytes_left = FLEX_ARRAY_BASE_SIZE - element_offset;
- return bytes_left;
-}
-
-static inline int nr_base_part_ptrs(void)
-{
- return bytes_left_in_base() / sizeof(struct flex_array_part *);
-}
-
/*
* If a user requests an allocation which is small
* enough, we may simply use the space in the
static inline int elements_fit_in_base(struct flex_array *fa)
{
int data_size = fa->element_size * fa->total_nr_elements;
- if (data_size <= bytes_left_in_base())
+ if (data_size <= FLEX_ARRAY_BASE_BYTES_LEFT)
return 1;
return 0;
}
* flex_array_alloc - allocate a new flexible array
* @element_size: the size of individual elements in the array
* @total: total number of elements that this should hold
+ * @flags: page allocation flags to use for base array
*
* Note: all locking must be provided by the caller.
*
* 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);
+ int max_size = FLEX_ARRAY_NR_BASE_PTRS *
+ FLEX_ARRAY_ELEMENTS_PER_PART(element_size);
/* max_size will end up 0 if element_size > PAGE_SIZE */
if (total > max_size)
return NULL;
ret->element_size = element_size;
ret->total_nr_elements = total;
+ if (elements_fit_in_base(ret) && !(flags & __GFP_ZERO))
+ memset(ret->parts[0], FLEX_ARRAY_FREE,
+ FLEX_ARRAY_BASE_BYTES_LEFT);
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);
+ return element_nr / FLEX_ARRAY_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.
+ * @fa: the flex array from which to free parts
*
* This is to be used in cases where the base 'struct flex_array'
* has been statically allocated and should not be free.
void flex_array_free_parts(struct flex_array *fa)
{
int part_nr;
- int max_part = nr_base_part_ptrs();
if (elements_fit_in_base(fa))
return;
- for (part_nr = 0; part_nr < max_part; part_nr++)
+ for (part_nr = 0; part_nr < FLEX_ARRAY_NR_BASE_PTRS; part_nr++)
kfree(fa->parts[part_nr]);
}
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 %
+ FLEX_ARRAY_ELEMENTS_PER_PART(fa->element_size);
return part_offset * fa->element_size;
}
{
struct flex_array_part *part = fa->parts[part_nr];
if (!part) {
- /*
- * This leaves the part pages uninitialized
- * and with potentially random data, just
- * as if the user had kmalloc()'d the whole.
- * __GFP_ZERO can be used to zero it.
- */
- part = kmalloc(FLEX_ARRAY_PART_SIZE, flags);
+ part = kmalloc(sizeof(struct flex_array_part), flags);
if (!part)
return NULL;
+ if (!(flags & __GFP_ZERO))
+ memset(part, FLEX_ARRAY_FREE,
+ sizeof(struct flex_array_part));
fa->parts[part_nr] = part;
}
return part;
/**
* flex_array_put - copy data into the array at @element_nr
- * @src: address of data to copy into the array
+ * @fa: the flex array to copy data into
* @element_nr: index of the position in which to insert
* the new element.
+ * @src: address of data to copy into the array
+ * @flags: page allocation flags to use for array expansion
+ *
*
* Note that this *copies* the contents of @src into
* the array. If you are trying to store an array of
*
* 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;
return -ENOSPC;
if (elements_fit_in_base(fa))
part = (struct flex_array_part *)&fa->parts[0];
- else
+ else {
part = __fa_get_part(fa, part_nr, flags);
- if (!part)
- return -ENOMEM;
+ if (!part)
+ return -ENOMEM;
+ }
dst = &part->elements[index_inside_part(fa, element_nr)];
memcpy(dst, src, fa->element_size);
return 0;
}
/**
+ * flex_array_clear - clear element in array at @element_nr
+ * @fa: the flex array of the element.
+ * @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, FLEX_ARRAY_FREE, fa->element_size);
+ return 0;
+}
+
+/**
* 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
*
* This will guarantee that no future calls to flex_array_put()
* will allocate memory. It can be used if you are expecting to
*
* 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;
/**
* flex_array_get - pull data back out of the array
+ * @fa: the flex array from which to extract data
* @element_nr: index of the element to fetch from the array
*
* Returns a pointer to the data at index @element_nr. Note
*
* 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;
- int index;
if (element_nr >= fa->total_nr_elements)
return NULL;
- if (!fa->parts[part_nr])
- return NULL;
if (elements_fit_in_base(fa))
part = (struct flex_array_part *)&fa->parts[0];
- else
+ else {
part = fa->parts[part_nr];
- index = index_inside_part(fa, element_nr);
+ if (!part)
+ return NULL;
+ }
return &part->elements[index_inside_part(fa, element_nr)];
}
+
+static int part_is_free(struct flex_array_part *part)
+{
+ int i;
+
+ for (i = 0; i < sizeof(struct flex_array_part); i++)
+ if (part->elements[i] != FLEX_ARRAY_FREE)
+ return 0;
+ return 1;
+}
+
+/**
+ * flex_array_shrink - free unused second-level pages
+ * @fa: the flex array to shrink
+ *
+ * Frees all second-level pages that consist solely of unused
+ * elements. Returns the number of pages freed.
+ *
+ * Locking must be provided by the caller.
+ */
+int flex_array_shrink(struct flex_array *fa)
+{
+ struct flex_array_part *part;
+ int part_nr;
+ int ret = 0;
+
+ if (elements_fit_in_base(fa))
+ return ret;
+ for (part_nr = 0; part_nr < FLEX_ARRAY_NR_BASE_PTRS; part_nr++) {
+ part = fa->parts[part_nr];
+ if (!part)
+ continue;
+ if (part_is_free(part)) {
+ fa->parts[part_nr] = NULL;
+ kfree(part);
+ ret++;
+ }
+ }
+ return ret;
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff