mm/cma_sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * CMA SysFS Interface
   4  *
   5  * Copyright (c) 2021 Minchan Kim <minchan@kernel.org>
   6  */
   7
   8 #include <linux/cma.h>
   9 #include <linux/kernel.h>
  10 #include <linux/slab.h>
  11
  12 #include "cma.h"
  13
  14 #define CMA_ATTR_RO(_name) \
  15         static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
  16
  17 void cma_sysfs_account_success_pages(struct cma *cma, unsigned long nr_pages)
  18 {
  19         atomic64_add(nr_pages, &cma->nr_pages_succeeded);
  20 }
  21
  22 void cma_sysfs_account_fail_pages(struct cma *cma, unsigned long nr_pages)
  23 {
  24         atomic64_add(nr_pages, &cma->nr_pages_failed);
  25 }
  26
  27 static inline struct cma *cma_from_kobj(struct kobject *kobj)
  28 {
  29         return container_of(kobj, struct cma_kobject, kobj)->cma;
  30 }
  31
  32 static ssize_t alloc_pages_success_show(struct kobject *kobj,
  33                                         struct kobj_attribute *attr, char *buf)
  34 {
  35         struct cma *cma = cma_from_kobj(kobj);
  36
  37         return sysfs_emit(buf, "%llu\n",
  38                           atomic64_read(&cma->nr_pages_succeeded));
  39 }
  40 CMA_ATTR_RO(alloc_pages_success);
  41
  42 static ssize_t alloc_pages_fail_show(struct kobject *kobj,
  43                                      struct kobj_attribute *attr, char *buf)
  44 {
  45         struct cma *cma = cma_from_kobj(kobj);
  46
  47         return sysfs_emit(buf, "%llu\n", atomic64_read(&cma->nr_pages_failed));
  48 }
  49 CMA_ATTR_RO(alloc_pages_fail);
  50
  51 static void cma_kobj_release(struct kobject *kobj)
  52 {
  53         struct cma *cma = cma_from_kobj(kobj);
  54         struct cma_kobject *cma_kobj = cma->cma_kobj;
  55
  56         kfree(cma_kobj);
  57         cma->cma_kobj = NULL;
  58 }
  59
  60 static struct attribute *cma_attrs[] = {
  61         &alloc_pages_success_attr.attr,
  62         &alloc_pages_fail_attr.attr,
  63         NULL,
  64 };
  65 ATTRIBUTE_GROUPS(cma);
  66
  67 static const struct kobj_type cma_ktype = {
  68         .release = cma_kobj_release,
  69         .sysfs_ops = &kobj_sysfs_ops,
  70         .default_groups = cma_groups,
  71 };
  72
  73 static int __init cma_sysfs_init(void)
  74 {
  75         struct kobject *cma_kobj_root;
  76         struct cma_kobject *cma_kobj;
  77         struct cma *cma;
  78         int i, err;
  79
  80         cma_kobj_root = kobject_create_and_add("cma", mm_kobj);
  81         if (!cma_kobj_root)
  82                 return -ENOMEM;
  83
  84         for (i = 0; i < cma_area_count; i++) {
  85                 cma_kobj = kzalloc(sizeof(*cma_kobj), GFP_KERNEL);
  86                 if (!cma_kobj) {
  87                         err = -ENOMEM;
  88                         goto out;
  89                 }
  90
  91                 cma = &cma_areas[i];
  92                 cma->cma_kobj = cma_kobj;
  93                 cma_kobj->cma = cma;
  94                 err = kobject_init_and_add(&cma_kobj->kobj, &cma_ktype,
  95                                            cma_kobj_root, "%s", cma->name);
  96                 if (err) {
  97                         kobject_put(&cma_kobj->kobj);
  98                         goto out;
  99                 }
 100         }
 101
 102         return 0;
 103 out:
 104         while (--i >= 0) {
 105                 cma = &cma_areas[i];
 106                 kobject_put(&cma->cma_kobj->kobj);
 107         }
 108         kobject_put(cma_kobj_root);
 109
 110         return err;
 111 }
 112 subsys_initcall(cma_sysfs_init);