x86/percpu: Declare const_pcpu_hot as extern const variable

ubizjak · Ingo Molnar · commit 4604c052b84d · 2023-11-30T20:19:33.000+01:00
const_pcpu_hot is aliased by linker to pcpu_hot, so there is no need to use the DECLARE_PER_CPU_ALIGNED() macro. Also, declare const_pcpu_hot as extern to avoid allocating storage space for the aliased structure. Fixes: ed2f752 ("x86/percpu: Introduce const-qualified const_pcpu_hot to micro-optimize code generation") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20231130162949.83518-1-ubizjak@gmail.com Closes: https://lore.kernel.org/oe-kbuild-all/202311302257.tSFtZnly-lkp@intel.com/
diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h
@@ -37,8 +37,7 @@ static_assert(sizeof(struct pcpu_hot) == 64);
 DECLARE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot);
 
 /* const-qualified alias to pcpu_hot, aliased by linker. */
-DECLARE_PER_CPU_ALIGNED(const struct pcpu_hot __percpu_seg_override,
-			const_pcpu_hot);
+extern const struct pcpu_hot __percpu_seg_override const_pcpu_hot;
 
 static __always_inline struct task_struct *get_current(void)
 {

Original file line number	Diff line number	Diff line change
`@@ -37,8 +37,7 @@ static_assert(sizeof(struct pcpu_hot) == 64);`
`37`	`37`	`DECLARE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot);`
`38`	`38`
`39`	`39`	`/* const-qualified alias to pcpu_hot, aliased by linker. */`
`40`		`-DECLARE_PER_CPU_ALIGNED(const struct pcpu_hot __percpu_seg_override,`
`41`		`- const_pcpu_hot);`
	`40`	`+extern const struct pcpu_hot __percpu_seg_override const_pcpu_hot;`
`42`	`41`
`43`	`42`	`static __always_inline struct task_struct *get_current(void)`
`44`	`43`	`{`