We get 1 warning when building kernel with W=1: drivers/char/mem.c:220:12: warning: no previous prototype for 'phys_mem_access_prot_allowed' [-Wmissing-prototypes] int __weak phys_mem_access_prot_allowed(struct file *file, In fact, its declaration is spreading to several header files in different architecture, but need to be declare in common header file. So this patch moves phys_mem_access_prot_allowed() to pgtable.h. Signed-off-by: Baoyou Xie <baoyou.xie@xxxxxxxxxx> --- arch/mips/include/asm/pgtable.h | 2 -- arch/x86/include/asm/pgtable_types.h | 2 -- include/asm-generic/pgtable.h | 3 +++ 3 files changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h index 70128d3..9e9e944 100644 --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -673,8 +673,6 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, struct file; pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot); -int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, - unsigned long size, pgprot_t *vma_prot); #endif /* diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index f1218f5..8b4de22 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -439,8 +439,6 @@ extern pgprot_t pgprot_writethrough(pgprot_t prot); struct file; pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot); -int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, - unsigned long size, pgprot_t *vma_prot); /* Install a pte for a particular vaddr in kernel space. */ void set_pte_vaddr(unsigned long vaddr, pte_t pte); diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index d4458b6..c4f8fd2 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -800,6 +800,9 @@ static inline int pmd_clear_huge(pmd_t *pmd) #endif #endif +struct file; +int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, + unsigned long size, pgprot_t *vma_prot); #endif /* !__ASSEMBLY__ */ #ifndef io_remap_pfn_range -- 2.7.4