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authorLinus Torvalds <torvalds@linux-foundation.org>2020-06-19 11:45:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-19 11:45:03 -0700
commit98b769942c698e43117334332ebfed852dfa6ff9 (patch)
tree2f4ac674b58d93bed26f7e8f25ff0e8465e60b4b
parent98d7e741a0a37fff24f99e4b6c5a1bd1e50cd47a (diff)
parentb19d57d0f3cc6f1022edf94daf1d70506a09e3c2 (diff)
downloadlinux-sh-98b769942c698e43117334332ebfed852dfa6ff9.tar.gz
Merge tag 'overflow-v5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull flex-array size helper from Kees Cook: "During the treewide clean-ups of zero-length "flexible arrays", the struct_size() helper was heavily used, but it was noticed that many times it would have been nice to have an additional helper to get the size of just the flexible array itself. This need appears to be even more common when cleaning up the 1-byte array "flexible arrays", so Gustavo implemented it. I'd love to get this landed early so it can be used during the v5.9 dev cycle to ease the 1-byte array cleanups." * tag 'overflow-v5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: overflow.h: Add flex_array_size() helper
-rw-r--r--include/linux/overflow.h25
1 files changed, 21 insertions, 4 deletions
diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index 659045046468..93fcef105061 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -304,16 +304,33 @@ static inline __must_check size_t __ab_c_size(size_t a, size_t b, size_t c)
* struct_size() - Calculate size of structure with trailing array.
* @p: Pointer to the structure.
* @member: Name of the array member.
- * @n: Number of elements in the array.
+ * @count: Number of elements in the array.
*
* Calculates size of memory needed for structure @p followed by an
- * array of @n @member elements.
+ * array of @count number of @member elements.
*
* Return: number of bytes needed or SIZE_MAX on overflow.
*/
-#define struct_size(p, member, n) \
- __ab_c_size(n, \
+#define struct_size(p, member, count) \
+ __ab_c_size(count, \
sizeof(*(p)->member) + __must_be_array((p)->member),\
sizeof(*(p)))
+/**
+ * flex_array_size() - Calculate size of a flexible array member
+ * within an enclosing structure.
+ *
+ * @p: Pointer to the structure.
+ * @member: Name of the flexible array member.
+ * @count: Number of elements in the array.
+ *
+ * Calculates size of a flexible array of @count number of @member
+ * elements, at the end of structure @p.
+ *
+ * Return: number of bytes needed or SIZE_MAX on overflow.
+ */
+#define flex_array_size(p, member, count) \
+ array_size(count, \
+ sizeof(*(p)->member) + __must_be_array((p)->member))
+
#endif /* __LINUX_OVERFLOW_H */