1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Device Mapper Uevent Support (dm-uevent) 4 * 5 * Copyright IBM Corporation, 2007 6 * Author: Mike Anderson <andmike@linux.vnet.ibm.com> 7 */ 8 #include <linux/list.h> 9 #include <linux/slab.h> 10 #include <linux/kobject.h> 11 #include <linux/dm-ioctl.h> 12 #include <linux/export.h> 13 14 #include "dm.h" 15 #include "dm-uevent.h" 16 17 #define DM_MSG_PREFIX "uevent" 18 19 static const struct { 20 enum dm_uevent_type type; 21 enum kobject_action action; 22 char *name; 23 } _dm_uevent_type_names[] = { 24 {DM_UEVENT_PATH_FAILED, KOBJ_CHANGE, "PATH_FAILED"}, 25 {DM_UEVENT_PATH_REINSTATED, KOBJ_CHANGE, "PATH_REINSTATED"}, 26 }; 27 28 static struct kmem_cache *_dm_event_cache; 29 30 struct dm_uevent { 31 struct mapped_device *md; 32 enum kobject_action action; 33 struct kobj_uevent_env ku_env; 34 struct list_head elist; 35 char name[DM_NAME_LEN]; 36 char uuid[DM_UUID_LEN]; 37 }; 38 39 static void dm_uevent_free(struct dm_uevent *event) 40 { 41 kmem_cache_free(_dm_event_cache, event); 42 } 43 44 static struct dm_uevent *dm_uevent_alloc(struct mapped_device *md) 45 { 46 struct dm_uevent *event; 47 48 event = kmem_cache_zalloc(_dm_event_cache, GFP_ATOMIC); 49 if (!event) 50 return NULL; 51 52 INIT_LIST_HEAD(&event->elist); 53 event->md = md; 54 55 return event; 56 } 57 58 static struct dm_uevent *dm_build_path_uevent(struct mapped_device *md, 59 struct dm_target *ti, 60 enum kobject_action action, 61 const char *dm_action, 62 const char *path, 63 unsigned int nr_valid_paths) 64 { 65 struct dm_uevent *event; 66 67 event = dm_uevent_alloc(md); 68 if (!event) { 69 DMERR("%s: dm_uevent_alloc() failed", __func__); 70 goto err_nomem; 71 } 72 73 event->action = action; 74 75 if (add_uevent_var(&event->ku_env, "DM_TARGET=%s", ti->type->name)) { 76 DMERR("%s: add_uevent_var() for DM_TARGET failed", 77 __func__); 78 goto err_add; 79 } 80 81 if (add_uevent_var(&event->ku_env, "DM_ACTION=%s", dm_action)) { 82 DMERR("%s: add_uevent_var() for DM_ACTION failed", 83 __func__); 84 goto err_add; 85 } 86 87 if (add_uevent_var(&event->ku_env, "DM_SEQNUM=%u", 88 dm_next_uevent_seq(md))) { 89 DMERR("%s: add_uevent_var() for DM_SEQNUM failed", 90 __func__); 91 goto err_add; 92 } 93 94 if (add_uevent_var(&event->ku_env, "DM_PATH=%s", path)) { 95 DMERR("%s: add_uevent_var() for DM_PATH failed", __func__); 96 goto err_add; 97 } 98 99 if (add_uevent_var(&event->ku_env, "DM_NR_VALID_PATHS=%d", 100 nr_valid_paths)) { 101 DMERR("%s: add_uevent_var() for DM_NR_VALID_PATHS failed", 102 __func__); 103 goto err_add; 104 } 105 106 return event; 107 108 err_add: 109 dm_uevent_free(event); 110 err_nomem: 111 return ERR_PTR(-ENOMEM); 112 } 113 114 /** 115 * dm_send_uevents - send uevents for given list 116 * 117 * @events: list of events to send 118 * @kobj: kobject generating event 119 * 120 */ 121 void dm_send_uevents(struct list_head *events, struct kobject *kobj) 122 { 123 int r; 124 struct dm_uevent *event, *next; 125 126 list_for_each_entry_safe(event, next, events, elist) { 127 list_del_init(&event->elist); 128 129 /* 130 * When a device is being removed this copy fails and we 131 * discard these unsent events. 132 */ 133 if (dm_copy_name_and_uuid(event->md, event->name, 134 event->uuid)) { 135 DMINFO("%s: skipping sending uevent for lost device", 136 __func__); 137 goto uevent_free; 138 } 139 140 if (add_uevent_var(&event->ku_env, "DM_NAME=%s", event->name)) { 141 DMERR("%s: add_uevent_var() for DM_NAME failed", 142 __func__); 143 goto uevent_free; 144 } 145 146 if (add_uevent_var(&event->ku_env, "DM_UUID=%s", event->uuid)) { 147 DMERR("%s: add_uevent_var() for DM_UUID failed", 148 __func__); 149 goto uevent_free; 150 } 151 152 r = kobject_uevent_env(kobj, event->action, event->ku_env.envp); 153 if (r) 154 DMERR("%s: kobject_uevent_env failed", __func__); 155 uevent_free: 156 dm_uevent_free(event); 157 } 158 } 159 EXPORT_SYMBOL_GPL(dm_send_uevents); 160 161 /** 162 * dm_path_uevent - called to create a new path event and queue it 163 * 164 * @event_type: path event type enum 165 * @ti: pointer to a dm_target 166 * @path: string containing pathname 167 * @nr_valid_paths: number of valid paths remaining 168 * 169 */ 170 void dm_path_uevent(enum dm_uevent_type event_type, struct dm_target *ti, 171 const char *path, unsigned int nr_valid_paths) 172 { 173 struct mapped_device *md = dm_table_get_md(ti->table); 174 struct dm_uevent *event; 175 176 if (event_type >= ARRAY_SIZE(_dm_uevent_type_names)) { 177 DMERR("%s: Invalid event_type %d", __func__, event_type); 178 return; 179 } 180 181 event = dm_build_path_uevent(md, ti, 182 _dm_uevent_type_names[event_type].action, 183 _dm_uevent_type_names[event_type].name, 184 path, nr_valid_paths); 185 if (IS_ERR(event)) 186 return; 187 188 dm_uevent_add(md, &event->elist); 189 } 190 EXPORT_SYMBOL_GPL(dm_path_uevent); 191 192 int dm_uevent_init(void) 193 { 194 _dm_event_cache = KMEM_CACHE(dm_uevent, 0); 195 if (!_dm_event_cache) 196 return -ENOMEM; 197 198 DMINFO("version 1.0.3"); 199 200 return 0; 201 } 202 203 void dm_uevent_exit(void) 204 { 205 kmem_cache_destroy(_dm_event_cache); 206 } 207