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>

4 files changed, 39 insertions, 37 deletions

diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 8b5ec19bdef4..0c44196b78ac 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -74,31 +74,31 @@ extern void __bad_percpu_size(void);
 
 #define percpu_to_op(op, var, val)                      \
 do {                                                    \
-        typedef typeof(var) T__;                        \
+        typedef typeof(var) pto_T__;                    \
         if (0) {                                        \
-                T__ tmp__;                              \
-                tmp__ = (val);                          \
+                pto_T__ pto_tmp__;                      \
+                pto_tmp__ = (val);                      \
         }                                               \
         switch (sizeof(var)) {                          \
         case 1:                                         \
                 asm(op "b %1,"__percpu_arg(0)           \
                     : "+m" (var)                        \
-                    : "qi" ((T__)(val)));               \
+                    : "qi" ((pto_T__)(val)));           \
                 break;                                  \
         case 2:                                         \
                 asm(op "w %1,"__percpu_arg(0)           \
                     : "+m" (var)                        \
-                    : "ri" ((T__)(val)));               \
+                    : "ri" ((pto_T__)(val)));           \
                 break;                                  \
         case 4:                                         \
                 asm(op "l %1,"__percpu_arg(0)           \
                     : "+m" (var)                        \
-                    : "ri" ((T__)(val)));               \
+                    : "ri" ((pto_T__)(val)));           \
                 break;                                  \
         case 8:                                         \
                 asm(op "q %1,"__percpu_arg(0)           \
                     : "+m" (var)                        \
-                    : "re" ((T__)(val)));               \
+                    : "re" ((pto_T__)(val)));           \
                 break;                                  \
         default: __bad_percpu_size();                   \
         }                                               \
@@ -106,31 +106,31 @@ do {							\
 
 #define percpu_from_op(op, var, constraint)             \
 ({                                                      \
-        typeof(var) ret__;                              \
+        typeof(var) pfo_ret__;                          \
         switch (sizeof(var)) {                          \
         case 1:                                         \
                 asm(op "b "__percpu_arg(1)",%0"         \
-                    : "=q" (ret__)                      \
+                    : "=q" (pfo_ret__)                  \
                     : constraint);                      \
                 break;                                  \
         case 2:                                         \
                 asm(op "w "__percpu_arg(1)",%0"         \
-                    : "=r" (ret__)                      \
+                    : "=r" (pfo_ret__)                  \
                     : constraint);                      \
                 break;                                  \
         case 4:                                         \
                 asm(op "l "__percpu_arg(1)",%0"         \
-                    : "=r" (ret__)                      \
+                    : "=r" (pfo_ret__)                  \
                     : constraint);                      \
                 break;                                  \
         case 8:                                         \
                 asm(op "q "__percpu_arg(1)",%0"         \
-                    : "=r" (ret__)                      \
+                    : "=r" (pfo_ret__)                  \
                     : constraint);                      \
                 break;                                  \
         default: __bad_percpu_size();                   \
         }                                               \
-        ret__;                                          \
+        pfo_ret__;                                      \
 })
 
 /*
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 */
diff --git a/mm/percpu.c b/mm/percpu.c
index ec158bb5f86d..e2e80fc78601 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -365,6 +365,7 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
  * 0 if noop, 1 if successfully extended, -errno on failure.
  */
 static int pcpu_extend_area_map(struct pcpu_chunk *chunk)
+        __releases(lock) __acquires(lock)
 {
         int new_alloc;
         int *new;