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.
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/percpu-defs.h | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index 7fa88c5f4b26..e1cf7982424f 100644
--- a/include/linux/percpu-defs.h
+++ b/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)
--
2.47.0
