1 files changed, 37 insertions, 11 deletions

diff --git a/lib/flex_array.c b/lib/flex_array.c
index c0ea40ba2082..cab7621f98aa 100644
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -88,8 +88,11 @@ struct flex_array *flex_array_alloc(int element_size, unsigned int total,
                                         gfp_t flags)
 {
         struct flex_array *ret;
-        int max_size = FLEX_ARRAY_NR_BASE_PTRS *
-                                FLEX_ARRAY_ELEMENTS_PER_PART(element_size);
+        int max_size = 0;
+
+        if (element_size)
+                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)
@@ -183,15 +186,18 @@ __fa_get_part(struct flex_array *fa, int part_nr, 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);
+        int part_nr;
         struct flex_array_part *part;
         void *dst;
 
         if (element_nr >= fa->total_nr_elements)
                 return -ENOSPC;
+        if (!fa->element_size)
+                return 0;
         if (elements_fit_in_base(fa))
                 part = (struct flex_array_part *)&fa->parts[0];
         else {
+                part_nr = fa_element_to_part_nr(fa, element_nr);
                 part = __fa_get_part(fa, part_nr, flags);
                 if (!part)
                         return -ENOMEM;
@@ -211,15 +217,18 @@ EXPORT_SYMBOL(flex_array_put);
  */
 int flex_array_clear(struct flex_array *fa, unsigned int element_nr)
 {
-        int part_nr = fa_element_to_part_nr(fa, element_nr);
+        int part_nr;
         struct flex_array_part *part;
         void *dst;
 
         if (element_nr >= fa->total_nr_elements)
                 return -ENOSPC;
+        if (!fa->element_size)
+                return 0;
         if (elements_fit_in_base(fa))
                 part = (struct flex_array_part *)&fa->parts[0];
         else {
+                part_nr = fa_element_to_part_nr(fa, element_nr);
                 part = fa->parts[part_nr];
                 if (!part)
                         return -EINVAL;
@@ -232,10 +241,10 @@ 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
@@ -245,15 +254,27 @@ 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;
 
-        if (start >= fa->total_nr_elements || end >= fa->total_nr_elements)
+        if (!start && !nr_elements)
+                return 0;
+        if (start >= fa->total_nr_elements)
+                return -ENOSPC;
+        if (!nr_elements)
+                return 0;
+
+        end = start + nr_elements - 1;
+
+        if (end >= fa->total_nr_elements)
                 return -ENOSPC;
+        if (!fa->element_size)
+                return 0;
         if (elements_fit_in_base(fa))
                 return 0;
         start_part = fa_element_to_part_nr(fa, start);
@@ -281,14 +302,17 @@ EXPORT_SYMBOL(flex_array_prealloc);
  */
 void *flex_array_get(struct flex_array *fa, unsigned int element_nr)
 {
-        int part_nr = fa_element_to_part_nr(fa, element_nr);
+        int part_nr;
         struct flex_array_part *part;
 
+        if (!fa->element_size)
+                return NULL;
         if (element_nr >= fa->total_nr_elements)
                 return NULL;
         if (elements_fit_in_base(fa))
                 part = (struct flex_array_part *)&fa->parts[0];
         else {
+                part_nr = fa_element_to_part_nr(fa, element_nr);
                 part = fa->parts[part_nr];
                 if (!part)
                         return NULL;
@@ -343,6 +367,8 @@ int flex_array_shrink(struct flex_array *fa)
         int part_nr;
         int ret = 0;
 
+        if (!fa->total_nr_elements || !fa->element_size)
+                return 0;
         if (elements_fit_in_base(fa))
                 return ret;
         for (part_nr = 0; part_nr < FLEX_ARRAY_NR_BASE_PTRS; part_nr++) {