From: David Howells <dhowells@xxxxxxxxxx>
Make watch_sizeof() give a build error if the size of the struct won't fit
into the size field in the header.
Reported-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
[Rebase to 5.10]
Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
---
include/linux/watch_queue.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/linux/watch_queue.h b/include/linux/watch_queue.h
index c994d1b2cdba..f1086d12cd03 100644
--- a/include/linux/watch_queue.h
+++ b/include/linux/watch_queue.h
@@ -120,7 +120,12 @@ static inline void remove_watch_list(struct watch_list *wlist, u64 id)
* watch_sizeof - Calculate the information part of the size of a watch record,
* given the structure size.
*/
-#define watch_sizeof(STRUCT) (sizeof(STRUCT) << WATCH_INFO_LENGTH__SHIFT)
+#define watch_sizeof(STRUCT) \
+ ({ \
+ size_t max = WATCH_INFO_LENGTH >> WATCH_INFO_LENGTH__SHIFT; \
+ BUILD_BUG_ON(sizeof(STRUCT) > max); \
+ sizeof(STRUCT) << WATCH_INFO_LENGTH__SHIFT; \
+ })
#else
static inline int watch_queue_init(struct pipe_inode_info *pipe)
--
2.28.0
