1 // SPDX-License-Identifier: GPL-2.0-only
5  * (C) Copyright 1991-2000 Linus Torvalds
7  * We have a per-user structure to keep track of how many
9  * able to have per-user limits for system resources. 
94 #define UIDHASH_MASK		(UIDHASH_SZ - 1)
104  * task-structs get RCU-freed. Hence all locking must be softirq-safe.
106  * local_bh_enable() with local interrupts disabled is an error - we'll run
122 static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)  in uid_hash_insert()  argument
124 	hlist_add_head(&up->uidhash_node, hashent);  in uid_hash_insert()
127 static void uid_hash_remove(struct user_struct *up)  in uid_hash_remove()  argument
129 	hlist_del_init(&up->uidhash_node);  in uid_hash_remove()
137 		if (uid_eq(user->uid, uid)) {  in uid_hash_find()
138 			refcount_inc(&user->__count);  in uid_hash_find()
146 static int user_epoll_alloc(struct user_struct *up)  in user_epoll_alloc()  argument
149 	return percpu_counter_init(&up->epoll_watches, 0, GFP_KERNEL);  in user_epoll_alloc()
155 static void user_epoll_free(struct user_struct *up)  in user_epoll_free()  argument
158 	percpu_counter_destroy(&up->epoll_watches);  in user_epoll_free()
166 static void free_user(struct user_struct *up, unsigned long flags)  in free_user()  argument
169 	uid_hash_remove(up);  in free_user()
171 	user_epoll_free(up);  in free_user()
172 	kmem_cache_free(uid_cachep, up);  in free_user()
192 void free_uid(struct user_struct *up)  in free_uid()  argument
196 	if (!up)  in free_uid()
199 	if (refcount_dec_and_lock_irqsave(&up->__count, &uidhash_lock, &flags))  in free_uid()
200 		free_user(up, flags);  in free_uid()
207 	struct user_struct *up, *new;  in alloc_uid()  local
210 	up = uid_hash_find(uid, hashent);  in alloc_uid()
213 	if (!up) {  in alloc_uid()
218 		new->uid = uid;  in alloc_uid()
219 		refcount_set(&new->__count, 1);  in alloc_uid()
224 		ratelimit_state_init(&new->ratelimit, HZ, 100);  in alloc_uid()
225 		ratelimit_set_flags(&new->ratelimit, RATELIMIT_MSG_ON_RELEASE);  in alloc_uid()
232 		up = uid_hash_find(uid, hashent);  in alloc_uid()
233 		if (up) {  in alloc_uid()
238 			up = new;  in alloc_uid()
243 	return up;  in alloc_uid()