Re: [PATCH v2 5/6] s390/uv: replace scnprintf with sysfs_emit

[Janosch Frank]

On 5/19/23 11:37, Steffen Eiden wrote:
> Replace scnprintf(page, PAGE_SIZE, ...) with the page size aware
> sysfs_emit(page, ...) which adds some sanity checks.
>
> Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
> ---
>   arch/s390/kernel/uv.c | 36 +++++++++++++++---------------------
>   1 file changed, 15 insertions(+), 21 deletions(-)
>
> diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
> index cb2ee06df286..d5b5d7e83c17 100644
> --- a/arch/s390/kernel/uv.c
> +++ b/arch/s390/kernel/uv.c
> @@ -462,11 +462,11 @@ EXPORT_SYMBOL_GPL(arch_make_page_accessible);
>   static ssize_t uv_query_facilities(struct kobject *kobj,
>   				   struct kobj_attribute *attr, char *page)

The last argument is called buf so let's also change that over to make 
all of the functions look the same.

>   {
> -	return scnprintf(page, PAGE_SIZE, "%lx\n%lx\n%lx\n%lx\n",
> -			uv_info.inst_calls_list[0],
> -			uv_info.inst_calls_list[1],
> -			uv_info.inst_calls_list[2],
> -			uv_info.inst_calls_list[3]);
> +	return sysfs_emit(page, "%lx\n%lx\n%lx\n%lx\n",
> +			  uv_info.inst_calls_list[0],
> +			  uv_info.inst_calls_list[1],
> +			  uv_info.inst_calls_list[2],
> +			  uv_info.inst_calls_list[3]);
>   }
>   
>   static struct kobj_attribute uv_query_facilities_attr =
> @@ -493,8 +493,7 @@ static struct kobj_attribute uv_query_supp_se_hdr_pcf_attr =
>   static ssize_t uv_query_dump_cpu_len(struct kobject *kobj,
>   				     struct kobj_attribute *attr, char *page)
>   {
> -	return scnprintf(page, PAGE_SIZE, "%lx\n",
> -			uv_info.guest_cpu_stor_len);
> +	return sysfs_emit(page, "%lx\n", uv_info.guest_cpu_stor_len);
>   }
>   
>   static struct kobj_attribute uv_query_dump_cpu_len_attr =
> @@ -503,8 +502,7 @@ static struct kobj_attribute uv_query_dump_cpu_len_attr =
>   static ssize_t uv_query_dump_storage_state_len(struct kobject *kobj,
>   					       struct kobj_attribute *attr, char *page)
>   {
> -	return scnprintf(page, PAGE_SIZE, "%lx\n",
> -			uv_info.conf_dump_storage_state_len);
> +	return sysfs_emit(page, "%lx\n", uv_info.conf_dump_storage_state_len);
>   }
>   
>   static struct kobj_attribute uv_query_dump_storage_state_len_attr =
> @@ -513,8 +511,7 @@ static struct kobj_attribute uv_query_dump_storage_state_len_attr =
>   static ssize_t uv_query_dump_finalize_len(struct kobject *kobj,
>   					  struct kobj_attribute *attr, char *page)
>   {
> -	return scnprintf(page, PAGE_SIZE, "%lx\n",
> -			uv_info.conf_dump_finalize_len);
> +	return sysfs_emit(page, "%lx\n", uv_info.conf_dump_finalize_len);
>   }
>   
>   static struct kobj_attribute uv_query_dump_finalize_len_attr =
> @@ -532,8 +529,7 @@ static struct kobj_attribute uv_query_feature_indications_attr =
>   static ssize_t uv_query_max_guest_cpus(struct kobject *kobj,
>   				       struct kobj_attribute *attr, char *page)
>   {
> -	return scnprintf(page, PAGE_SIZE, "%d\n",
> -			uv_info.max_guest_cpu_id + 1);
> +	return sysfs_emit(page, "%d\n", uv_info.max_guest_cpu_id + 1);
>   }
>   
>   static struct kobj_attribute uv_query_max_guest_cpus_attr =
> @@ -542,8 +538,7 @@ static struct kobj_attribute uv_query_max_guest_cpus_attr =
>   static ssize_t uv_query_max_guest_vms(struct kobject *kobj,
>   				      struct kobj_attribute *attr, char *page)
>   {
> -	return scnprintf(page, PAGE_SIZE, "%d\n",
> -			uv_info.max_num_sec_conf);
> +	return sysfs_emit(page, "%d\n", uv_info.max_num_sec_conf);
>   }
>   
>   static struct kobj_attribute uv_query_max_guest_vms_attr =
> @@ -552,8 +547,7 @@ static struct kobj_attribute uv_query_max_guest_vms_attr =
>   static ssize_t uv_query_max_guest_addr(struct kobject *kobj,
>   				       struct kobj_attribute *attr, char *page)
>   {
> -	return scnprintf(page, PAGE_SIZE, "%lx\n",
> -			uv_info.max_sec_stor_addr);
> +	return sysfs_emit(page, "%lx\n", uv_info.max_sec_stor_addr);
>   }
>   
>   static struct kobj_attribute uv_query_max_guest_addr_attr =
> @@ -562,7 +556,7 @@ static struct kobj_attribute uv_query_max_guest_addr_attr =
>   static ssize_t uv_query_supp_att_req_hdr_ver(struct kobject *kobj,
>   					     struct kobj_attribute *attr, char *page)
>   {
> -	return scnprintf(page, PAGE_SIZE, "%lx\n", uv_info.supp_att_req_hdr_ver);
> +	return sysfs_emit(page, "%lx\n", uv_info.supp_att_req_hdr_ver);
>   }
>   
>   static struct kobj_attribute uv_query_supp_att_req_hdr_ver_attr =
> @@ -571,7 +565,7 @@ static struct kobj_attribute uv_query_supp_att_req_hdr_ver_attr =
>   static ssize_t uv_query_supp_att_pflags(struct kobject *kobj,
>   					struct kobj_attribute *attr, char *page)
>   {
> -	return scnprintf(page, PAGE_SIZE, "%lx\n", uv_info.supp_att_pflags);
> +	return sysfs_emit(page, "%lx\n", uv_info.supp_att_pflags);
>   }
>   
>   static struct kobj_attribute uv_query_supp_att_pflags_attr =
> @@ -605,7 +599,7 @@ static ssize_t uv_is_prot_virt_guest(struct kobject *kobj,
>   #ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
>   	val = prot_virt_guest;
>   #endif
> -	return scnprintf(page, PAGE_SIZE, "%d\n", val);
> +	return sysfs_emit(page, "%d\n", val);
>   }
>   
>   static ssize_t uv_is_prot_virt_host(struct kobject *kobj,
> @@ -617,7 +611,7 @@ static ssize_t uv_is_prot_virt_host(struct kobject *kobj,
>   	val = prot_virt_host;
>   #endif
>   
> -	return scnprintf(page, PAGE_SIZE, "%d\n", val);
> +	return sysfs_emit(page, "%d\n", val);
>   }
>   
>   static struct kobj_attribute uv_prot_virt_guest =