[PATCH] asm-generic: replace ________addr with __UNIQUE_ID(addr)

Min-Hsun Chang
2026-03-07T09:22:05Z

The macro __set_fixmap_offset() uses a hardcoded identifier ________addr,
which can lead to variable name shadowing if a caller happens to use the
same name in its scope.

Following the pattern in commit 44238e82670e ("rcu: Replace ________p1 and
_________p1 with __UNIQUE_ID(rcu)") and commit 589a9785ee3a ("min/max:
remove sparse warnings when they're nested"), replace the hardcoded
identifier with __UNIQUE_ID(addr).

Since __UNIQUE_ID() must be expanded once to remain consistent across
declaration, assignment, and return within the statement expression,
introduce a nested helper macro ___set_fixmap_offset.

Signed-off-by: Min-Hsun Chang <chmh0624@gmail.com>
---
include/asm-generic/fixmap.h | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h
index 29cab7947980..2d1e9a2c6a3b 100644
--- a/include/asm-generic/fixmap.h
+++ b/include/asm-generic/fixmap.h
@@ -16,6 +16,7 @@
#define __ASM_GENERIC_FIXMAP_H

#include <linux/bug.h>
+#include <linux/compiler.h>
#include <linux/mm_types.h>

#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
@@ -71,14 +72,17 @@ static inline unsigned long virt_to_fix(const unsigned long vaddr)
#endif

/* Return a pointer with offset calculated */
-#define __set_fixmap_offset(idx, phys, flags) \
-({ \
- unsigned long ________addr; \
- __set_fixmap(idx, phys, flags); \
- ________addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1)); \
- ________addr; \
+#define ___set_fixmap_offset(idx, phys, flags, uniq) \
+({ \
+ unsigned long uniq; \
+ __set_fixmap(idx, phys, flags); \
+ uniq = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1)); \
+ uniq; \
})

+#define __set_fixmap_offset(idx, phys, flags) \
+ ___set_fixmap_offset(idx, phys, flags, __UNIQUE_ID(addr))
+
#define set_fixmap_offset(idx, phys) \
__set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)

--
2.50.1