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Subject[PATCH 1/3] mm: generalize VM_BUG_ON() macros
Date
This patch makes VM_BUG_ON() to accept one to three arguments after the
condition. Any of these arguments can be page, vma or mm. VM_BUG_ON()
will dump info about the argument using appropriate dump_* function.

It's intended to replace separate VM_BUG_ON_PAGE(), VM_BUG_ON_VMA(),
VM_BUG_ON_MM() and allows additional use-cases like:

VM_BUG_ON(cond, vma, page);
VM_BUG_ON(cond, vma, src_page, dst_page);
VM_BUG_ON(cond, mm, src_vma, dst_vma);
...

It's possible to extend list of supported data-structures or number of
arguments VM_BUG_ON() can accept.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
include/linux/mmdebug.h | 49 ++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 38 insertions(+), 11 deletions(-)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 877ef226f90f..12f304a36b01 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -14,33 +14,60 @@ void dump_vma(const struct vm_area_struct *vma);
void dump_mm(const struct mm_struct *mm);

#ifdef CONFIG_DEBUG_VM
-#define VM_BUG_ON(cond) BUG_ON(cond)
-#define VM_BUG_ON_PAGE(cond, page) \
+#define GET_MACRO(_1, _2, _3, _4, NAME, ...) NAME
+
+#define _VM_DUMP(arg, cond) do { \
+ if (__builtin_types_compatible_p(typeof(*arg), struct page)) \
+ dump_page((struct page *) arg, \
+ "VM_BUG_ON(" __stringify(cond)")"); \
+ else if (__builtin_types_compatible_p(typeof(*arg), \
+ struct vm_area_struct)) \
+ dump_vma((struct vm_area_struct *) arg); \
+ else if (__builtin_types_compatible_p(typeof(*arg), \
+ struct mm_struct)) \
+ dump_mm((struct mm_struct *) arg); \
+ else \
+ BUILD_BUG(); \
+} while(0)
+
+#define _VM_BUG_ON_ARG1(cond, arg1) \
do { \
if (unlikely(cond)) { \
- dump_page(page, "VM_BUG_ON_PAGE(" __stringify(cond)")");\
+ _VM_DUMP(arg1, cond); \
BUG(); \
} \
- } while (0)
-#define VM_BUG_ON_VMA(cond, vma) \
+ } while(0)
+#define _VM_BUG_ON_ARG2(cond, arg1, arg2) \
do { \
if (unlikely(cond)) { \
- dump_vma(vma); \
+ _VM_DUMP(arg1, cond); \
+ _VM_DUMP(arg2, cond); \
BUG(); \
} \
- } while (0)
-#define VM_BUG_ON_MM(cond, mm) \
+ } while(0)
+#define _VM_BUG_ON_ARG3(cond, arg1, arg2, arg3) \
do { \
if (unlikely(cond)) { \
- dump_mm(mm); \
+ _VM_DUMP(arg1, cond); \
+ _VM_DUMP(arg2, cond); \
+ _VM_DUMP(arg3, cond); \
BUG(); \
} \
- } while (0)
+ } while(0)
+
+#define VM_BUG_ON(...) GET_MACRO(__VA_ARGS__, \
+ _VM_BUG_ON_ARG3, \
+ _VM_BUG_ON_ARG2, \
+ _VM_BUG_ON_ARG1, \
+ BUG_ON)(__VA_ARGS__)
+#define VM_BUG_ON_PAGE VM_BUG_ON
+#define VM_BUG_ON_VMA VM_BUG_ON
+#define VM_BUG_ON_MM VM_BUG_ON
#define VM_WARN_ON(cond) WARN_ON(cond)
#define VM_WARN_ON_ONCE(cond) WARN_ON_ONCE(cond)
#define VM_WARN_ONCE(cond, format...) WARN_ONCE(cond, format)
#else
-#define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
+#define VM_BUG_ON(cond, ...) BUILD_BUG_ON_INVALID(cond)
#define VM_BUG_ON_PAGE(cond, page) VM_BUG_ON(cond)
#define VM_BUG_ON_VMA(cond, vma) VM_BUG_ON(cond)
#define VM_BUG_ON_MM(cond, mm) VM_BUG_ON(cond)
--
2.1.0


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