projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 6ab42860 TH |
1 | /** |
| 2 | * css_get - obtain a reference on the specified css | |
| 3 | * @css: target css | |
| 4 | * | |
| 5 | * The caller must already have a reference. | |
| 6 | */ | |
| 7 | CGROUP_REF_FN_ATTRS | |
| 8 | void css_get(struct cgroup_subsys_state *css) | |
| 9 | { | |
| 10 | if (!(css->flags & CSS_NO_REF)) | |
| 11 | percpu_ref_get(&css->refcnt); | |
| 12 | } | |
| 79a7f41f | 13 | CGROUP_REF_EXPORT(css_get) |
| 6ab42860 TH |
14 | |
| 15 | /** | |
| 16 | * css_get_many - obtain references on the specified css | |
| 17 | * @css: target css | |
| 18 | * @n: number of references to get | |
| 19 | * | |
| 20 | * The caller must already have a reference. | |
| 21 | */ | |
| 22 | CGROUP_REF_FN_ATTRS | |
| 23 | void css_get_many(struct cgroup_subsys_state *css, unsigned int n) | |
| 24 | { | |
| 25 | if (!(css->flags & CSS_NO_REF)) | |
| 26 | percpu_ref_get_many(&css->refcnt, n); | |
| 27 | } | |
| 79a7f41f | 28 | CGROUP_REF_EXPORT(css_get_many) |
| 6ab42860 TH |
29 | |
| 30 | /** | |
| 31 | * css_tryget - try to obtain a reference on the specified css | |
| 32 | * @css: target css | |
| 33 | * | |
| 34 | * Obtain a reference on @css unless it already has reached zero and is | |
| 35 | * being released. This function doesn't care whether @css is on or | |
| 36 | * offline. The caller naturally needs to ensure that @css is accessible | |
| 37 | * but doesn't have to be holding a reference on it - IOW, RCU protected | |
| 38 | * access is good enough for this function. Returns %true if a reference | |
| 39 | * count was successfully obtained; %false otherwise. | |
| 40 | */ | |
| 41 | CGROUP_REF_FN_ATTRS | |
| 42 | bool css_tryget(struct cgroup_subsys_state *css) | |
| 43 | { | |
| 44 | if (!(css->flags & CSS_NO_REF)) | |
| 45 | return percpu_ref_tryget(&css->refcnt); | |
| 46 | return true; | |
| 47 | } | |
| 79a7f41f | 48 | CGROUP_REF_EXPORT(css_tryget) |
| 6ab42860 TH |
49 | |
| 50 | /** | |
| 51 | * css_tryget_online - try to obtain a reference on the specified css if online | |
| 52 | * @css: target css | |
| 53 | * | |
| 54 | * Obtain a reference on @css if it's online. The caller naturally needs | |
| 55 | * to ensure that @css is accessible but doesn't have to be holding a | |
| 56 | * reference on it - IOW, RCU protected access is good enough for this | |
| 57 | * function. Returns %true if a reference count was successfully obtained; | |
| 58 | * %false otherwise. | |
| 59 | */ | |
| 60 | CGROUP_REF_FN_ATTRS | |
| 61 | bool css_tryget_online(struct cgroup_subsys_state *css) | |
| 62 | { | |
| 63 | if (!(css->flags & CSS_NO_REF)) | |
| 64 | return percpu_ref_tryget_live(&css->refcnt); | |
| 65 | return true; | |
| 66 | } | |
| 79a7f41f | 67 | CGROUP_REF_EXPORT(css_tryget_online) |
| 6ab42860 TH |
68 | |
| 69 | /** | |
| 70 | * css_put - put a css reference | |
| 71 | * @css: target css | |
| 72 | * | |
| 73 | * Put a reference obtained via css_get() and css_tryget_online(). | |
| 74 | */ | |
| 75 | CGROUP_REF_FN_ATTRS | |
| 76 | void css_put(struct cgroup_subsys_state *css) | |
| 77 | { | |
| 78 | if (!(css->flags & CSS_NO_REF)) | |
| 79 | percpu_ref_put(&css->refcnt); | |
| 80 | } | |
| 79a7f41f | 81 | CGROUP_REF_EXPORT(css_put) |
| 6ab42860 TH |
82 | |
| 83 | /** | |
| 84 | * css_put_many - put css references | |
| 85 | * @css: target css | |
| 86 | * @n: number of references to put | |
| 87 | * | |
| 88 | * Put references obtained via css_get() and css_tryget_online(). | |
| 89 | */ | |
| 90 | CGROUP_REF_FN_ATTRS | |
| 91 | void css_put_many(struct cgroup_subsys_state *css, unsigned int n) | |
| 92 | { | |
| 93 | if (!(css->flags & CSS_NO_REF)) | |
| 94 | percpu_ref_put_many(&css->refcnt, n); | |
| 95 | } | |
| 79a7f41f | 96 | CGROUP_REF_EXPORT(css_put_many) |