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authorEric Paris <eparis@redhat.com>2011-04-28 15:55:52 -0400
committerEric Paris <eparis@redhat.com>2011-04-28 16:12:54 -0400
commitbf69d41d198138e3c601e9a6645f4f1369aff7e0 (patch)
tree6cd3c35430f616732caa0096bd7791b56c8bd3ab /lib
parent5d30b10bd68df007e7ae21e77d1e0ce184b53040 (diff)
downloadlinux-bf69d41d198138e3c601e9a6645f4f1369aff7e0.tar.gz
flex_arrays: allow zero length flex arrays
Just like kmalloc will allow one to allocate a 0 length segment of memory flex arrays should do the same thing. It should bomb if you try to use something, but it should at least allow the allocation. This is needed because when SELinux switched to using flex_arrays in 2.6.38 the inability to allocate a 0 length array resulted in SELinux policy load returning -ENOSPC when previously it worked. 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> Cc: stable@kernel.org [2.6.38+]
Diffstat (limited to 'lib')
-rw-r--r--lib/flex_array.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/lib/flex_array.c b/lib/flex_array.c
index 0c33b24498b..854b57bd7d9 100644
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -253,9 +253,16 @@ int flex_array_prealloc(struct flex_array *fa, unsigned int start,
unsigned int end;
struct flex_array_part *part;
+ 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 (start >= fa->total_nr_elements || end >= fa->total_nr_elements)
+ if (end >= fa->total_nr_elements)
return -ENOSPC;
if (elements_fit_in_base(fa))
return 0;
@@ -346,6 +353,8 @@ int flex_array_shrink(struct flex_array *fa)
int part_nr;
int ret = 0;
+ if (!fa->total_nr_elements)
+ return 0;
if (elements_fit_in_base(fa))
return ret;
for (part_nr = 0; part_nr < FLEX_ARRAY_NR_BASE_PTRS; part_nr++) {