cleanup: Annotate guard constructors with nonnull

Add __nonnull_args() to unconditional guard constructors so the compiler
warns when NULL is statically known to be passed:

- DEFINE_GUARD(): re-declare the constructor with __nonnull_args().
- __DEFINE_LOCK_GUARD_1(): annotate the constructor directly.

DEFINE_LOCK_GUARD_0() needs no annotation: its constructor takes no
pointer arguments (.lock is hardcoded to (void *)1).

Define the __nonnull_args() macro in compiler_attributes.h, following
the existing convention for attribute wrappers. Deliberately not named
'__nonnull', to avoid clashing with glibc's __nonnull() when kernel and
userspace headers are combined (User Mode Linux for example).

Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/85fee12eec20abfcf711443518e8f0caec982a86.1780064327.git.d@ilvokhin.com
This commit is contained in:
Dmitry Ilvokhin 2026-06-02 07:12:52 +00:00 • committed by Peter Zijlstra
commit 22302af28d
2 changed files with 12 additions and 1 deletions