Re: [PATCH 1/2] erofs: add sysfs interface

[Huang Jianan via Linux-erofs]

在 2021/11/9 11:14, Joe Perches 写道:

On Tue, 2021-11-09 at 10:54 +0800, Huang Jianan wrote:

Add sysfs interface to configure erofs related parameters in the
future.

[]

diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c

[]

+static ssize_t erofs_attr_show(struct kobject *kobj,
+                               struct attribute *attr, char *buf)
+{
+       struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
+                                               s_kobj);
+       struct erofs_attr *a = container_of(attr, struct erofs_attr, attr);
+       unsigned char *ptr = __struct_ptr(sbi, a->struct_type, a->offset);
+
+       switch (a->attr_id) {
+       case attr_feature:
+               return snprintf(buf, PAGE_SIZE, "supported\n");
+       case attr_pointer_ui:
+               if (!ptr)
+                       return 0;
+               return snprintf(buf, PAGE_SIZE, "%u\n",
+                               *((unsigned int *) ptr));

Prefer sysfs_emit over snprintf

        case attr_feature:
                return sysfs_emit(buf, "supported\n");
        case attr_pointer_ui:
                ...
                return sysfs_emit(buf, "%u\n", *(unsigned int *)ptr);

etc...

Thanks for reminding this, I will fix it in the next version.

Thanks,
Jianan