From 18ab890cdc1e014d2ced35a5b8e606871ed5e6fc Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Apr 2011 15:55:52 -0400 Subject: [PATCH] flex_arrays: allow zero length flex arrays commit bf69d41d198138e3c601e9a6645f4f1369aff7e0 upstream. 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 Signed-off-by: Eric Paris Tested-by: Chris Richards Signed-off-by: Greg Kroah-Hartman --- lib/flex_array.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/lib/flex_array.c b/lib/flex_array.c index 0c33b24498ba..854b57bd7d9d 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++) { -- 2.39.5