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![Christoph Lameter](/assets/img/avatar_default.png)
Replace all uses of kmem_cache_t with struct kmem_cache. The patch was generated using the following script: #!/bin/sh # # Replace one string by another in all the kernel sources. # set -e for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do quilt add $file sed -e "1,\$s/$1/$2/g" $file >/tmp/$$ mv /tmp/$$ $file quilt refresh done The script was run like this sh replace kmem_cache_t "struct kmem_cache" Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
224 lines
5.4 KiB
C
224 lines
5.4 KiB
C
/*
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* The "user cache".
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*
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* (C) Copyright 1991-2000 Linus Torvalds
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*
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* We have a per-user structure to keep track of how many
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* processes, files etc the user has claimed, in order to be
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* able to have per-user limits for system resources.
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*/
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/bitops.h>
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#include <linux/key.h>
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#include <linux/interrupt.h>
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/*
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* UID task count cache, to get fast user lookup in "alloc_uid"
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* when changing user ID's (ie setuid() and friends).
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*/
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#define UIDHASH_BITS (CONFIG_BASE_SMALL ? 3 : 8)
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#define UIDHASH_SZ (1 << UIDHASH_BITS)
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#define UIDHASH_MASK (UIDHASH_SZ - 1)
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#define __uidhashfn(uid) (((uid >> UIDHASH_BITS) + uid) & UIDHASH_MASK)
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#define uidhashentry(uid) (uidhash_table + __uidhashfn((uid)))
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static struct kmem_cache *uid_cachep;
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static struct list_head uidhash_table[UIDHASH_SZ];
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/*
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* The uidhash_lock is mostly taken from process context, but it is
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* occasionally also taken from softirq/tasklet context, when
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* task-structs get RCU-freed. Hence all locking must be softirq-safe.
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* But free_uid() is also called with local interrupts disabled, and running
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* local_bh_enable() with local interrupts disabled is an error - we'll run
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* softirq callbacks, and they can unconditionally enable interrupts, and
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* the caller of free_uid() didn't expect that..
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*/
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static DEFINE_SPINLOCK(uidhash_lock);
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struct user_struct root_user = {
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.__count = ATOMIC_INIT(1),
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.processes = ATOMIC_INIT(1),
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.files = ATOMIC_INIT(0),
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.sigpending = ATOMIC_INIT(0),
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.mq_bytes = 0,
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.locked_shm = 0,
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#ifdef CONFIG_KEYS
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.uid_keyring = &root_user_keyring,
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.session_keyring = &root_session_keyring,
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#endif
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};
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/*
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* These routines must be called with the uidhash spinlock held!
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*/
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static inline void uid_hash_insert(struct user_struct *up, struct list_head *hashent)
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{
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list_add(&up->uidhash_list, hashent);
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}
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static inline void uid_hash_remove(struct user_struct *up)
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{
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list_del(&up->uidhash_list);
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}
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static inline struct user_struct *uid_hash_find(uid_t uid, struct list_head *hashent)
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{
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struct list_head *up;
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list_for_each(up, hashent) {
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struct user_struct *user;
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user = list_entry(up, struct user_struct, uidhash_list);
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if(user->uid == uid) {
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atomic_inc(&user->__count);
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return user;
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}
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}
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return NULL;
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}
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/*
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* Locate the user_struct for the passed UID. If found, take a ref on it. The
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* caller must undo that ref with free_uid().
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*
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* If the user_struct could not be found, return NULL.
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*/
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struct user_struct *find_user(uid_t uid)
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{
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struct user_struct *ret;
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unsigned long flags;
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spin_lock_irqsave(&uidhash_lock, flags);
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ret = uid_hash_find(uid, uidhashentry(uid));
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spin_unlock_irqrestore(&uidhash_lock, flags);
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return ret;
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}
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void free_uid(struct user_struct *up)
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{
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unsigned long flags;
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if (!up)
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return;
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local_irq_save(flags);
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if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
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uid_hash_remove(up);
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spin_unlock_irqrestore(&uidhash_lock, flags);
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key_put(up->uid_keyring);
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key_put(up->session_keyring);
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kmem_cache_free(uid_cachep, up);
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} else {
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local_irq_restore(flags);
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}
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}
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struct user_struct * alloc_uid(uid_t uid)
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{
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struct list_head *hashent = uidhashentry(uid);
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struct user_struct *up;
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spin_lock_irq(&uidhash_lock);
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up = uid_hash_find(uid, hashent);
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spin_unlock_irq(&uidhash_lock);
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if (!up) {
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struct user_struct *new;
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new = kmem_cache_alloc(uid_cachep, GFP_KERNEL);
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if (!new)
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return NULL;
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new->uid = uid;
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atomic_set(&new->__count, 1);
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atomic_set(&new->processes, 0);
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atomic_set(&new->files, 0);
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atomic_set(&new->sigpending, 0);
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#ifdef CONFIG_INOTIFY_USER
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atomic_set(&new->inotify_watches, 0);
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atomic_set(&new->inotify_devs, 0);
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#endif
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new->mq_bytes = 0;
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new->locked_shm = 0;
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if (alloc_uid_keyring(new, current) < 0) {
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kmem_cache_free(uid_cachep, new);
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return NULL;
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}
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/*
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* Before adding this, check whether we raced
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* on adding the same user already..
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*/
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spin_lock_irq(&uidhash_lock);
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up = uid_hash_find(uid, hashent);
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if (up) {
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key_put(new->uid_keyring);
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key_put(new->session_keyring);
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kmem_cache_free(uid_cachep, new);
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} else {
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uid_hash_insert(new, hashent);
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up = new;
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}
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spin_unlock_irq(&uidhash_lock);
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}
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return up;
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}
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void switch_uid(struct user_struct *new_user)
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{
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struct user_struct *old_user;
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/* What if a process setreuid()'s and this brings the
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* new uid over his NPROC rlimit? We can check this now
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* cheaply with the new uid cache, so if it matters
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* we should be checking for it. -DaveM
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*/
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old_user = current->user;
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atomic_inc(&new_user->processes);
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atomic_dec(&old_user->processes);
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switch_uid_keyring(new_user);
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current->user = new_user;
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/*
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* We need to synchronize with __sigqueue_alloc()
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* doing a get_uid(p->user).. If that saw the old
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* user value, we need to wait until it has exited
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* its critical region before we can free the old
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* structure.
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*/
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smp_mb();
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spin_unlock_wait(¤t->sighand->siglock);
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free_uid(old_user);
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suid_keys(current);
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}
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static int __init uid_cache_init(void)
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{
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int n;
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uid_cachep = kmem_cache_create("uid_cache", sizeof(struct user_struct),
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0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
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for(n = 0; n < UIDHASH_SZ; ++n)
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INIT_LIST_HEAD(uidhash_table + n);
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/* Insert the root user immediately (init already runs as root) */
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spin_lock_irq(&uidhash_lock);
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uid_hash_insert(&root_user, uidhashentry(0));
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spin_unlock_irq(&uidhash_lock);
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return 0;
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}
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module_init(uid_cache_init);
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