Re: [PATCH v4 05/11] s390: Change s390_kernel_write() return type to match memcpy()

Jiri Kosina
2020-05-07T13:36:53Z

On Wed, 29 Apr 2020, Josh Poimboeuf wrote:

> s390_kernel_write()'s function type is almost identical to memcpy().
> Change its return type to "void *" so they can be used interchangeably.
>
> Cc: linux-s390@vger.kernel.org
> Cc: heiko.carstens@de.ibm.com
> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
> Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
> Acked-by: Miroslav Benes <mbenes@suse.cz>

Also for this one -- s390 folks, could you please provide your Ack for
taking things through livepatching.git as part of this series?

Thanks.

> ---
> arch/s390/include/asm/uaccess.h | 2 +-
> arch/s390/mm/maccess.c | 9 ++++++---
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
> index a470f1fa9f2a..324438889fe1 100644
> --- a/arch/s390/include/asm/uaccess.h
> +++ b/arch/s390/include/asm/uaccess.h
> @@ -276,6 +276,6 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo
> }
>
> int copy_to_user_real(void __user *dest, void *src, unsigned long count);
> -void s390_kernel_write(void *dst, const void *src, size_t size);
> +void *s390_kernel_write(void *dst, const void *src, size_t size);
>
> #endif /* __S390_UACCESS_H */
> diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
> index de7ca4b6718f..22a0be655f27 100644
> --- a/arch/s390/mm/maccess.c
> +++ b/arch/s390/mm/maccess.c
> @@ -55,19 +55,22 @@ static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t siz
> */
> static DEFINE_SPINLOCK(s390_kernel_write_lock);
>
> -void notrace s390_kernel_write(void *dst, const void *src, size_t size)
> +notrace void *s390_kernel_write(void *dst, const void *src, size_t size)
> {
> + void *tmp = dst;
> unsigned long flags;
> long copied;
>
> spin_lock_irqsave(&s390_kernel_write_lock, flags);
> while (size) {
> - copied = s390_kernel_write_odd(dst, src, size);
> - dst += copied;
> + copied = s390_kernel_write_odd(tmp, src, size);
> + tmp += copied;
> src += copied;
> size -= copied;
> }
> spin_unlock_irqrestore(&s390_kernel_write_lock, flags);
> +
> + return dst;
> }
>
> static int __no_sanitize_address __memcpy_real(void *dest, void *src, size_t count)
> --
> 2.21.1
>

--
Jiri Kosina
SUSE Labs