The patch titled
Subject: percpu: introduce PERCPU_PTR() macro
has been added to the -mm mm-nonmm-unstable branch. Its filename is
percpu-introduce-percpu_ptr-macro.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/percpu-introduce-percpu_ptr-macro.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Uros Bizjak <ubizjak@xxxxxxxxx>
Subject: percpu: introduce PERCPU_PTR() macro
Date: Mon, 21 Oct 2024 10:07:37 +0200
Introduce PERCPU_PTR() macro to cast the percpu pointer from the percpu
address space to a generic (kernel) address space. Use it in
per_cpu_ptr() and related SHIFT_PERCPU_PTR() macros.
Also remove common knowledge from SHIFT_PERCPU_PTR() comment, "weird cast"
is just a standard way to inform sparse of a cast from the percpu address
space to a generic address space.
Link: https://lkml.kernel.org/r/20241021080856.48746-2-ubizjak@xxxxxxxxx
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Acked-by: Christoph Lameter <cl@xxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/percpu-defs.h | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
--- a/include/linux/percpu-defs.h~percpu-introduce-percpu_ptr-macro
+++ a/include/linux/percpu-defs.h
@@ -220,15 +220,17 @@ do { \
(void)__vpp_verify; \
} while (0)
+#define PERCPU_PTR(__p) \
+ (typeof(*(__p)) __force __kernel *)(__p);
+
#ifdef CONFIG_SMP
/*
- * Add an offset to a pointer but keep the pointer as-is. Use RELOC_HIDE()
- * to prevent the compiler from making incorrect assumptions about the
- * pointer value. The weird cast keeps both GCC and sparse happy.
+ * Add an offset to a pointer. Use RELOC_HIDE() to prevent the compiler
+ * from making incorrect assumptions about the pointer value.
*/
#define SHIFT_PERCPU_PTR(__p, __offset) \
- RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset))
+ RELOC_HIDE(PERCPU_PTR(__p), (__offset))
#define per_cpu_ptr(ptr, cpu) \
({ \
@@ -258,7 +260,7 @@ do { \
({ \
(void)(cpu); \
__verify_pcpu_ptr(ptr); \
- (typeof(*(ptr)) __kernel __force *)(ptr); \
+ PERCPU_PTR(ptr); \
})
#define raw_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
_
Patches currently in -mm which might be from ubizjak@xxxxxxxxx are
perf-hw_breakpoint-use-err_ptr_pcpu-is_err_pcpu-and-ptr_err_pcpu-macros.patch
percpu-merge-verify_percpu_ptr-into-its-only-user.patch
percpu-introduce-percpu_ptr-macro.patch
percpu-cast-percpu-pointer-in-percpu_ptr-via-unsigned-long.patch
