[PATCH v3] locking/local_lock: s/l/__l/ and s/tl/__tl/ to reduce risk of shadowing

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

From: Vincent Mailhol <mailhol@kernel.org>

The Linux kernel coding style advises to avoid common variable
names in function-like macros to reduce the risk of collisions.

Throughout local_lock_internal.h, several macros use the rather common
variable names 'l' and 'tl'. This already resulted in an actual
collision: the __local_lock_acquire() function like macro is currently
shadowing the parameter 'l' of the:

  class_##_name##_t class_##_name##_constructor(_type *l)

function factory from linux/cleanup.h.

Rename the variable 'l' to '__l' and the variable 'tl' to '__tl'
throughout the file to fix the current name collision and to prevent
future ones.

[ bigeasy: Rebase, update all l and tl instances in macros ]

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---

Looks harmless enough to make everyone happy.

v2…v3: 
  - Rebase

v1…v2: https://lore.kernel.org/all/20250925-local_lock_internal_fix_shadow-v2-1-d3b85ee775a4@kernel.org/

  - __lock conflicted with an existing definition in lockdep.c. Use
    instead __l (and also, to keep things consistent, use __tl instead
    of tl for the trylock).

  - Apply the renaming to the entire file and not just to
    __local_lock_acquire().

  - Rewrite the patch description accordingly.

v1: https://lore.kernel.org/r/20250923-local_lock_internal_fix_shadow-v1-1-14e313c88a46@kernel.org

 include/linux/local_lock_internal.h | 62 ++++++++++++++---------------
 1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
index a4dc479157b5c..8f82b4eb542f2 100644
--- a/include/linux/local_lock_internal.h
+++ b/include/linux/local_lock_internal.h
@@ -99,18 +99,18 @@ do {								\
 
 #define __local_lock_acquire(lock)					\
 	do {								\
-		local_trylock_t *tl;					\
-		local_lock_t *l;					\
+		local_trylock_t *__tl;					\
+		local_lock_t *__l;					\
 									\
-		l = (local_lock_t *)(lock);				\
-		tl = (local_trylock_t *)l;				\
+		__l = (local_lock_t *)(lock);				\
+		__tl = (local_trylock_t *)__l;				\
 		_Generic((lock),					\
 			local_trylock_t *: ({				\
-				lockdep_assert(tl->acquired == 0);	\
-				WRITE_ONCE(tl->acquired, 1);		\
+				lockdep_assert(__tl->acquired == 0);	\
+				WRITE_ONCE(__tl->acquired, 1);		\
 			}),						\
 			local_lock_t *: (void)0);			\
-		local_lock_acquire(l);					\
+		local_lock_acquire(__l);				\
 	} while (0)
 
 #define __local_lock(lock)					\
@@ -133,36 +133,36 @@ do {								\
 
 #define __local_trylock(lock)					\
 	({							\
-		local_trylock_t *tl;				\
+		local_trylock_t *__tl;				\
 								\
 		preempt_disable();				\
-		tl = (lock);					\
-		if (READ_ONCE(tl->acquired)) {			\
+		__tl = (lock);					\
+		if (READ_ONCE(__tl->acquired)) {		\
 			preempt_enable();			\
-			tl = NULL;				\
+			__tl = NULL;				\
 		} else {					\
-			WRITE_ONCE(tl->acquired, 1);		\
+			WRITE_ONCE(__tl->acquired, 1);		\
 			local_trylock_acquire(			\
-				(local_lock_t *)tl);		\
+				(local_lock_t *)__tl);		\
 		}						\
-		!!tl;						\
+		!!__tl;						\
 	})
 
 #define __local_trylock_irqsave(lock, flags)			\
 	({							\
-		local_trylock_t *tl;				\
+		local_trylock_t *__tl;				\
 								\
 		local_irq_save(flags);				\
-		tl = (lock);					\
-		if (READ_ONCE(tl->acquired)) {			\
+		__tl = (lock);					\
+		if (READ_ONCE(__tl->acquired)) {		\
 			local_irq_restore(flags);		\
-			tl = NULL;				\
+			__tl = NULL;				\
 		} else {					\
-			WRITE_ONCE(tl->acquired, 1);		\
+			WRITE_ONCE(__tl->acquired, 1);		\
 			local_trylock_acquire(			\
-				(local_lock_t *)tl);		\
+				(local_lock_t *)__tl);		\
 		}						\
-		!!tl;						\
+		!!__tl;						\
 	})
 
 /* preemption or migration must be disabled before calling __local_lock_is_locked */
@@ -170,16 +170,16 @@ do {								\
 
 #define __local_lock_release(lock)					\
 	do {								\
-		local_trylock_t *tl;					\
-		local_lock_t *l;					\
+		local_trylock_t *__tl;					\
+		local_lock_t *__l;					\
 									\
-		l = (local_lock_t *)(lock);				\
-		tl = (local_trylock_t *)l;				\
-		local_lock_release(l);					\
+		__l = (local_lock_t *)(lock);				\
+		__tl = (local_trylock_t *)__l;				\
+		local_lock_release(__l);				\
 		_Generic((lock),					\
 			local_trylock_t *: ({				\
-				lockdep_assert(tl->acquired == 1);	\
-				WRITE_ONCE(tl->acquired, 0);		\
+				lockdep_assert(__tl->acquired == 1);	\
+				WRITE_ONCE(__tl->acquired, 0);		\
 			}),						\
 			local_lock_t *: (void)0);			\
 	} while (0)
@@ -223,12 +223,12 @@ typedef spinlock_t local_trylock_t;
 #define INIT_LOCAL_LOCK(lockname) __LOCAL_SPIN_LOCK_UNLOCKED((lockname))
 #define INIT_LOCAL_TRYLOCK(lockname) __LOCAL_SPIN_LOCK_UNLOCKED((lockname))
 
-#define __local_lock_init(l)					\
+#define __local_lock_init(__l)					\
 	do {							\
-		local_spin_lock_init((l));			\
+		local_spin_lock_init((__l));			\
 	} while (0)
 
-#define __local_trylock_init(l)			__local_lock_init(l)
+#define __local_trylock_init(__l)			__local_lock_init(__l)
 
 #define __local_lock(__lock)					\
 	do {							\
-- 
2.51.0