percpu: remove some sparse warnings

Make the following changes to remove some sparse warnings.

* Make DEFINE_PER_CPU_SECTION() declare __pcpu_unique_* before
  defining it.

* Annotate pcpu_extend_area_map() that it is entered with pcpu_lock
  held, releases it and then reacquires it.

* Make percpu related macros use unique nested variable names.

* While at it, add pcpu prefix to __size_call[_return]() macros as
  to-be-implemented sparse annotations will add percpu specific stuff
  to these macros.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>

2 files changed, 25 insertions, 24 deletions

diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index 9bd03193ecd4..5a5d6ce4bd55 100644
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -60,6 +60,7 @@
 
 #define DEFINE_PER_CPU_SECTION(type, name, sec)                         \
         __PCPU_DUMMY_ATTRS char __pcpu_scope_##name;                    \
+        extern __PCPU_DUMMY_ATTRS char __pcpu_unique_##name;            \
         __PCPU_DUMMY_ATTRS char __pcpu_unique_##name;                   \
         __PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES __weak                 \
         __typeof__(type) per_cpu__##name
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 519d6876590f..522f421ec213 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -226,20 +226,20 @@ do {									\
 
 extern void __bad_size_call_parameter(void);
 
-#define __size_call_return(stem, variable)                              \
-({      typeof(variable) ret__;                                         \
+#define __pcpu_size_call_return(stem, variable)                         \
+({      typeof(variable) pscr_ret__;                                    \
         switch(sizeof(variable)) {                                      \
-        case 1: ret__ = stem##1(variable);break;                        \
-        case 2: ret__ = stem##2(variable);break;                        \
-        case 4: ret__ = stem##4(variable);break;                        \
-        case 8: ret__ = stem##8(variable);break;                        \
+        case 1: pscr_ret__ = stem##1(variable);break;                   \
+        case 2: pscr_ret__ = stem##2(variable);break;                   \
+        case 4: pscr_ret__ = stem##4(variable);break;                   \
+        case 8: pscr_ret__ = stem##8(variable);break;                   \
         default:                                                        \
                 __bad_size_call_parameter();break;                      \
         }                                                               \
-        ret__;                                                          \
+        pscr_ret__;                                                     \
 })
 
-#define __size_call(stem, variable, ...)                                \
+#define __pcpu_size_call(stem, variable, ...)                           \
 do {                                                                    \
         switch(sizeof(variable)) {                                      \
                 case 1: stem##1(variable, __VA_ARGS__);break;           \
@@ -299,7 +299,7 @@ do {									\
 # ifndef this_cpu_read_8
 #  define this_cpu_read_8(pcp)  _this_cpu_generic_read(pcp)
 # endif
-# define this_cpu_read(pcp)     __size_call_return(this_cpu_read_, (pcp))
+# define this_cpu_read(pcp)     __pcpu_size_call_return(this_cpu_read_, (pcp))
 #endif
 
 #define _this_cpu_generic_to_op(pcp, val, op)                           \
@@ -322,7 +322,7 @@ do {									\
 # ifndef this_cpu_write_8
 #  define this_cpu_write_8(pcp, val)    _this_cpu_generic_to_op((pcp), (val), =)
 # endif
-# define this_cpu_write(pcp, val)       __size_call(this_cpu_write_, (pcp), (val))
+# define this_cpu_write(pcp, val)       __pcpu_size_call(this_cpu_write_, (pcp), (val))
 #endif
 
 #ifndef this_cpu_add
@@ -338,7 +338,7 @@ do {									\
 # ifndef this_cpu_add_8
 #  define this_cpu_add_8(pcp, val)      _this_cpu_generic_to_op((pcp), (val), +=)
 # endif
-# define this_cpu_add(pcp, val)         __size_call(this_cpu_add_, (pcp), (val))
+# define this_cpu_add(pcp, val)         __pcpu_size_call(this_cpu_add_, (pcp), (val))
 #endif
 
 #ifndef this_cpu_sub
@@ -366,7 +366,7 @@ do {									\
 # ifndef this_cpu_and_8
 #  define this_cpu_and_8(pcp, val)      _this_cpu_generic_to_op((pcp), (val), &=)
 # endif
-# define this_cpu_and(pcp, val)         __size_call(this_cpu_and_, (pcp), (val))
+# define this_cpu_and(pcp, val)         __pcpu_size_call(this_cpu_and_, (pcp), (val))
 #endif
 
 #ifndef this_cpu_or
@@ -382,7 +382,7 @@ do {									\
 # ifndef this_cpu_or_8
 #  define this_cpu_or_8(pcp, val)       _this_cpu_generic_to_op((pcp), (val), |=)
 # endif
-# define this_cpu_or(pcp, val)          __size_call(this_cpu_or_, (pcp), (val))
+# define this_cpu_or(pcp, val)          __pcpu_size_call(this_cpu_or_, (pcp), (val))
 #endif
 
 #ifndef this_cpu_xor
@@ -398,7 +398,7 @@ do {									\
 # ifndef this_cpu_xor_8
 #  define this_cpu_xor_8(pcp, val)      _this_cpu_generic_to_op((pcp), (val), ^=)
 # endif
-# define this_cpu_xor(pcp, val)         __size_call(this_cpu_or_, (pcp), (val))
+# define this_cpu_xor(pcp, val)         __pcpu_size_call(this_cpu_or_, (pcp), (val))
 #endif
 
 /*
@@ -428,7 +428,7 @@ do {									\
 # ifndef __this_cpu_read_8
 #  define __this_cpu_read_8(pcp)        (*__this_cpu_ptr(&(pcp)))
 # endif
-# define __this_cpu_read(pcp)   __size_call_return(__this_cpu_read_, (pcp))
+# define __this_cpu_read(pcp)   __pcpu_size_call_return(__this_cpu_read_, (pcp))
 #endif
 
 #define __this_cpu_generic_to_op(pcp, val, op)                          \
@@ -449,7 +449,7 @@ do {									\
 # ifndef __this_cpu_write_8
 #  define __this_cpu_write_8(pcp, val)  __this_cpu_generic_to_op((pcp), (val), =)
 # endif
-# define __this_cpu_write(pcp, val)     __size_call(__this_cpu_write_, (pcp), (val))
+# define __this_cpu_write(pcp, val)     __pcpu_size_call(__this_cpu_write_, (pcp), (val))
 #endif
 
 #ifndef __this_cpu_add
@@ -465,7 +465,7 @@ do {									\
 # ifndef __this_cpu_add_8
 #  define __this_cpu_add_8(pcp, val)    __this_cpu_generic_to_op((pcp), (val), +=)
 # endif
-# define __this_cpu_add(pcp, val)       __size_call(__this_cpu_add_, (pcp), (val))
+# define __this_cpu_add(pcp, val)       __pcpu_size_call(__this_cpu_add_, (pcp), (val))
 #endif
 
 #ifndef __this_cpu_sub
@@ -493,7 +493,7 @@ do {									\
 # ifndef __this_cpu_and_8
 #  define __this_cpu_and_8(pcp, val)    __this_cpu_generic_to_op((pcp), (val), &=)
 # endif
-# define __this_cpu_and(pcp, val)       __size_call(__this_cpu_and_, (pcp), (val))
+# define __this_cpu_and(pcp, val)       __pcpu_size_call(__this_cpu_and_, (pcp), (val))
 #endif
 
 #ifndef __this_cpu_or
@@ -509,7 +509,7 @@ do {									\
 # ifndef __this_cpu_or_8
 #  define __this_cpu_or_8(pcp, val)     __this_cpu_generic_to_op((pcp), (val), |=)
 # endif
-# define __this_cpu_or(pcp, val)        __size_call(__this_cpu_or_, (pcp), (val))
+# define __this_cpu_or(pcp, val)        __pcpu_size_call(__this_cpu_or_, (pcp), (val))
 #endif
 
 #ifndef __this_cpu_xor
@@ -525,7 +525,7 @@ do {									\
 # ifndef __this_cpu_xor_8
 #  define __this_cpu_xor_8(pcp, val)    __this_cpu_generic_to_op((pcp), (val), ^=)
 # endif
-# define __this_cpu_xor(pcp, val)       __size_call(__this_cpu_xor_, (pcp), (val))
+# define __this_cpu_xor(pcp, val)       __pcpu_size_call(__this_cpu_xor_, (pcp), (val))
 #endif
 
 /*
@@ -556,7 +556,7 @@ do {									\
 # ifndef irqsafe_cpu_add_8
 #  define irqsafe_cpu_add_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
 # endif
-# define irqsafe_cpu_add(pcp, val) __size_call(irqsafe_cpu_add_, (pcp), (val))
+# define irqsafe_cpu_add(pcp, val) __pcpu_size_call(irqsafe_cpu_add_, (pcp), (val))
 #endif
 
 #ifndef irqsafe_cpu_sub
@@ -584,7 +584,7 @@ do {									\
 # ifndef irqsafe_cpu_and_8
 #  define irqsafe_cpu_and_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
 # endif
-# define irqsafe_cpu_and(pcp, val) __size_call(irqsafe_cpu_and_, (val))
+# define irqsafe_cpu_and(pcp, val) __pcpu_size_call(irqsafe_cpu_and_, (val))
 #endif
 
 #ifndef irqsafe_cpu_or
@@ -600,7 +600,7 @@ do {									\
 # ifndef irqsafe_cpu_or_8
 #  define irqsafe_cpu_or_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
 # endif
-# define irqsafe_cpu_or(pcp, val) __size_call(irqsafe_cpu_or_, (val))
+# define irqsafe_cpu_or(pcp, val) __pcpu_size_call(irqsafe_cpu_or_, (val))
 #endif
 
 #ifndef irqsafe_cpu_xor
@@ -616,7 +616,7 @@ do {									\
 # ifndef irqsafe_cpu_xor_8
 #  define irqsafe_cpu_xor_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
 # endif
-# define irqsafe_cpu_xor(pcp, val) __size_call(irqsafe_cpu_xor_, (val))
+# define irqsafe_cpu_xor(pcp, val) __pcpu_size_call(irqsafe_cpu_xor_, (val))
 #endif
 
 #endif /* __LINUX_PERCPU_H */