linux-kernel - Re: [PATCH] um: Replace to_phys() and to_virt() with less generic function names

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Date:   Thu, 14 Jul 2022 21:12:08 +0100
From:   Anton Ivanov <anton.ivanov@...bridgegreys.com>
To:     Guenter Roeck <linux@...ck-us.net>,
        Richard Weinberger <richard@....at>
Cc:     Johannes Berg <johannes@...solutions.net>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-um@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Dan Williams <dan.j.williams@...el.com>,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH] um: Replace to_phys() and to_virt() with less generic
 function names

On 14/07/2022 19:46, Guenter Roeck wrote:
> to_virt() and to_phys() are very generic and may be defined by drivers.
> As it turns out, commit 9409c9b6709e ("pmem: refactor pmem_clear_poison()")
> did exactly that. This results in build errors such as the following
> when trying to build um:allmodconfig.
> 
> drivers/nvdimm/pmem.c: In function ‘pmem_dax_zero_page_range’:
> ./arch/um/include/asm/page.h:105:20: error:
> 			too few arguments to function ‘to_phys’
>    105 | #define __pa(virt) to_phys((void *) (unsigned long) (virt))
>        |                    ^~~~~~~
> 
> Use less generic function names for the um specific to_phys() and to_virt()
> functions to fix the problem and to avoid similar problems in the future.
> 
> Fixes: 9409c9b6709e ("pmem: refactor pmem_clear_poison()")
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: Christoph Hellwig <hch@....de>
> Signed-off-by: Guenter Roeck <linux@...ck-us.net>
> ---
>   arch/um/include/asm/page.h      | 4 ++--
>   arch/um/include/shared/mem.h    | 4 ++--
>   arch/um/os-Linux/skas/process.c | 6 +++---
>   3 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
> index 95af12e82a32..cdbd9653aa14 100644
> --- a/arch/um/include/asm/page.h
> +++ b/arch/um/include/asm/page.h
> @@ -102,8 +102,8 @@ extern unsigned long uml_physmem;
>    * casting is the right thing, but 32-bit UML can't have 64-bit virtual
>    * addresses
>    */
> -#define __pa(virt) to_phys((void *) (unsigned long) (virt))
> -#define __va(phys) to_virt((unsigned long) (phys))
> +#define __pa(virt) uml_to_phys((void *) (unsigned long) (virt))
> +#define __va(phys) uml_to_virt((unsigned long) (phys))
>   
>   #define phys_to_pfn(p) ((p) >> PAGE_SHIFT)
>   #define pfn_to_phys(pfn) PFN_PHYS(pfn)
> diff --git a/arch/um/include/shared/mem.h b/arch/um/include/shared/mem.h
> index 4862c91d4213..98aacd544108 100644
> --- a/arch/um/include/shared/mem.h
> +++ b/arch/um/include/shared/mem.h
> @@ -9,12 +9,12 @@
>   extern int phys_mapping(unsigned long phys, unsigned long long *offset_out);
>   
>   extern unsigned long uml_physmem;
> -static inline unsigned long to_phys(void *virt)
> +static inline unsigned long uml_to_phys(void *virt)
>   {
>   	return(((unsigned long) virt) - uml_physmem);
>   }
>   
> -static inline void *to_virt(unsigned long phys)
> +static inline void *uml_to_virt(unsigned long phys)
>   {
>   	return((void *) uml_physmem + phys);
>   }
> diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
> index 87d3129e7362..c316c993a949 100644
> --- a/arch/um/os-Linux/skas/process.c
> +++ b/arch/um/os-Linux/skas/process.c
> @@ -251,7 +251,7 @@ static int userspace_tramp(void *stack)
>   	signal(SIGTERM, SIG_DFL);
>   	signal(SIGWINCH, SIG_IGN);
>   
> -	fd = phys_mapping(to_phys(__syscall_stub_start), &offset);
> +	fd = phys_mapping(uml_to_phys(__syscall_stub_start), &offset);
>   	addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
>   		      PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
>   	if (addr == MAP_FAILED) {
> @@ -261,7 +261,7 @@ static int userspace_tramp(void *stack)
>   	}
>   
>   	if (stack != NULL) {
> -		fd = phys_mapping(to_phys(stack), &offset);
> +		fd = phys_mapping(uml_to_phys(stack), &offset);
>   		addr = mmap((void *) STUB_DATA,
>   			    UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
>   			    MAP_FIXED | MAP_SHARED, fd, offset);
> @@ -534,7 +534,7 @@ int copy_context_skas0(unsigned long new_stack, int pid)
>   	struct stub_data *data = (struct stub_data *) current_stack;
>   	struct stub_data *child_data = (struct stub_data *) new_stack;
>   	unsigned long long new_offset;
> -	int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
> +	int new_fd = phys_mapping(uml_to_phys((void *)new_stack), &new_offset);
>   
>   	/*
>   	 * prepare offset and fd of child's stack as argument for parent's

Acked-By: Anton Ivanov <anton.ivanov@...bridgegreys.com>

-- 
Anton R. Ivanov
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