[PATCH 4.9 2/9] mm: add VM_WARN_ON_ONCE_PAGE() macro

From: Greg Kroah-Hartman
Date: Fri Jul 09 2021 - 09:18:50 EST


From: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>

[ Upstream commit a4055888629bc0467d12d912cd7c90acdf3d9b12 part ]

Add VM_WARN_ON_ONCE_PAGE() macro.

Link: https://lkml.kernel.org/r/1604283436-18880-3-git-send-email-alex.shi@xxxxxxxxxxxxxxxxx
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

Note on stable backport: original commit was titled
mm/memcg: warning on !memcg after readahead page charged
which included uses of this macro in mm/memcontrol.c: here omitted.

Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/linux/mmdebug.h | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index deaba1cc3cfc..d1fb3bbff37a 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -36,6 +36,18 @@ void dump_mm(const struct mm_struct *mm);
BUG(); \
} \
} while (0)
+#define VM_WARN_ON_ONCE_PAGE(cond, page) ({ \
+ static bool __section(".data.once") __warned; \
+ int __ret_warn_once = !!(cond); \
+ \
+ if (unlikely(__ret_warn_once && !__warned)) { \
+ dump_page(page, "VM_WARN_ON_ONCE_PAGE(" __stringify(cond)")");\
+ __warned = true; \
+ WARN_ON(1); \
+ } \
+ unlikely(__ret_warn_once); \
+})
+
#define VM_WARN_ON(cond) (void)WARN_ON(cond)
#define VM_WARN_ON_ONCE(cond) (void)WARN_ON_ONCE(cond)
#define VM_WARN_ONCE(cond, format...) (void)WARN_ONCE(cond, format)
@@ -47,6 +59,7 @@ void dump_mm(const struct mm_struct *mm);
#define VM_BUG_ON_MM(cond, mm) VM_BUG_ON(cond)
#define VM_WARN_ON(cond) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN_ON_ONCE(cond) BUILD_BUG_ON_INVALID(cond)
+#define VM_WARN_ON_ONCE_PAGE(cond, page) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN_ONCE(cond, format...) BUILD_BUG_ON_INVALID(cond)
#define VM_WARN(cond, format...) BUILD_BUG_ON_INVALID(cond)
#endif
--
2.30.2