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/Documentation/flexible-arrays.txt b/Documentation/flexible-arrays.txt
index cb8a3a0..df904ae 100644 (file)
--- a/Documentation/flexible-arrays.txt
+++ b/Documentation/flexible-arrays.txt
@@ -66,10 +66,10 @@ trick is to ensure that any needed memory allocations are done before
 entering atomic context, using:
 
     int flex_array_prealloc(struct flex_array *array, unsigned int start,
-                           unsigned int end, gfp_t flags);
+                           unsigned int nr_elements, gfp_t flags);
 
 This function will ensure that memory for the elements indexed in the range
-defined by start and end has been allocated.  Thereafter, a
+defined by start and nr_elements has been allocated.  Thereafter, a
 flex_array_put() call on an element in that range is guaranteed not to
 block.
 

diff --git a/include/linux/flex_array.h b/include/linux/flex_array.h
index 70e4efa..ebeb2f3 100644 (file)
--- a/include/linux/flex_array.h
+++ b/include/linux/flex_array.h
@@ -61,7 +61,7 @@ struct flex_array {
 struct flex_array *flex_array_alloc(int element_size, unsigned int total,
                gfp_t flags);
 int flex_array_prealloc(struct flex_array *fa, unsigned int start,
-               unsigned int end, gfp_t flags);
+               unsigned int nr_elements, gfp_t flags);
 void flex_array_free(struct flex_array *fa);
 void flex_array_free_parts(struct flex_array *fa);
 int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,

diff --git a/lib/flex_array.c b/lib/flex_array.c
index c0ea40b..0c33b24 100644 (file)
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -232,10 +232,10 @@ EXPORT_SYMBOL(flex_array_clear);
 
 /**
  * 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 @@ EXPORT_SYMBOL(flex_array_clear);
  * 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))

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index e7b850a..e6e7ce0 100644 (file)
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -502,7 +502,7 @@ static int policydb_index(struct policydb *p)
                goto out;
 
        rc = flex_array_prealloc(p->type_val_to_struct_array, 0,
-                                p->p_types.nprim - 1, GFP_KERNEL | __GFP_ZERO);
+                                p->p_types.nprim, GFP_KERNEL | __GFP_ZERO);
        if (rc)
                goto out;
 
@@ -519,7 +519,7 @@ static int policydb_index(struct policydb *p)
                        goto out;
 
                rc = flex_array_prealloc(p->sym_val_to_name[i],
-                                        0, p->symtab[i].nprim - 1,
+                                        0, p->symtab[i].nprim,
                                         GFP_KERNEL | __GFP_ZERO);
                if (rc)
                        goto out;
@@ -2375,7 +2375,7 @@ int policydb_read(struct policydb *p, void *fp)
                goto bad;
 
        /* preallocate so we don't have to worry about the put ever failing */
-       rc = flex_array_prealloc(p->type_attr_map_array, 0, p->p_types.nprim - 1,
+       rc = flex_array_prealloc(p->type_attr_map_array, 0, p->p_types.nprim,
                                 GFP_KERNEL | __GFP_ZERO);
        if (rc)
                goto bad;