percpu: make accessors check for percpu pointer in sparse

The previous patch made sparse warn about percpu variables being used
directly without going through percpu accessors.  This patch
implements the other half - checking whether non percpu variable is
passed into percpu accessors.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 2 deletions

diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index fded453fd25c..04f91c2d3f7b 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -42,8 +42,10 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
  */
 #ifndef SHIFT_PERCPU_PTR
 /* Weird cast keeps both GCC and sparse happy. */
-#define SHIFT_PERCPU_PTR(__p, __offset)                         \
-        RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset))
+#define SHIFT_PERCPU_PTR(__p, __offset) ({                              \
+        __verify_pcpu_ptr((__p));                                       \
+        RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \
+})
 #endif
 
 /*