[PATCH v2 02/10] loongarch: fix duplicate extern declarations

[Safocl Stollmannovic <safocl88@gmail.com>]

Compiling a kernel module with a C++ compiler results in a "duplicate
extern specifier" error.
This occurs because the code contains `extern asmlinkage`, and `asmlinkage`
expands to `extern C` when processed by a C++ compiler.
Since the code already contains sections that respond to a C++ compiler,
I believe it is a perfectly valid approach to gradually move toward a state
where kernel modules can be compiled by a C++ compiler without any issues.
The `extern` specifier must be removed.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=222257

Signed-off-by: Safocl Stollmannovic <safocl88@gmail.com>
---
 arch/loongarch/include/asm/idle.h      | 2 +-
 arch/loongarch/include/asm/smp.h       | 4 ++--
 arch/loongarch/include/asm/switch_to.h | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/include/asm/idle.h b/arch/loongarch/include/asm/idle.h
index f7f2b7dbf..9913191cb 100644
--- a/arch/loongarch/include/asm/idle.h
+++ b/arch/loongarch/include/asm/idle.h
@@ -4,6 +4,6 @@
 
 #include <linux/linkage.h>
 
-extern asmlinkage void __arch_cpu_idle(void);
+asmlinkage void __arch_cpu_idle(void);
 
 #endif /* __ASM_IDLE_H  */
diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
index dd1457065..c21a5b60e 100644
--- a/arch/loongarch/include/asm/smp.h
+++ b/arch/loongarch/include/asm/smp.h
@@ -87,8 +87,8 @@ struct secondary_data {
 };
 extern struct secondary_data cpuboot_data;
 
-extern asmlinkage void smpboot_entry(void);
-extern asmlinkage void start_secondary(void);
+asmlinkage void smpboot_entry(void);
+asmlinkage void start_secondary(void);
 
 extern void calculate_cpu_foreign_map(void);
 
diff --git a/arch/loongarch/include/asm/switch_to.h b/arch/loongarch/include/asm/switch_to.h
index ab9e0292c..aa5d3da68 100644
--- a/arch/loongarch/include/asm/switch_to.h
+++ b/arch/loongarch/include/asm/switch_to.h
@@ -21,7 +21,7 @@ struct task_struct;
  * This function is used whilst scheduling to save the context of prev & load
  * the context of next. Returns prev.
  */
-extern asmlinkage struct task_struct *__switch_to(struct task_struct *prev,
+asmlinkage struct task_struct *__switch_to(struct task_struct *prev,
 			struct task_struct *next, void *sched_ra, void *sched_cfa);
 
 /*
-- 
2.56.1