![Linus Torvalds](/assets/img/avatar_default.png)
This reverts commit cb26a31157
.
It mysteriously causes NetworkManager to not find the wireless device
for me. As far as I can tell, Tejun *meant* for this commit to not make
any semantic changes, but there clearly are some. So revert it, taking
into account some of the calling convention changes that happened in
this area in subsequent commits.
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1147 lines
27 KiB
C
1147 lines
27 KiB
C
/*
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* fs/sysfs/dir.c - sysfs core and dir operation implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
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*
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* This file is released under the GPLv2.
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*
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* Please see Documentation/filesystems/sysfs.txt for more information.
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*/
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#undef DEBUG
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/module.h>
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#include <linux/kobject.h>
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#include <linux/namei.h>
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#include <linux/idr.h>
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#include <linux/completion.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/security.h>
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#include <linux/hash.h>
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#include "sysfs.h"
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DEFINE_MUTEX(sysfs_mutex);
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DEFINE_SPINLOCK(sysfs_symlink_target_lock);
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#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb)
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static DEFINE_SPINLOCK(sysfs_ino_lock);
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static DEFINE_IDA(sysfs_ino_ida);
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/**
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* sysfs_name_hash
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* @name: Null terminated string to hash
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* @ns: Namespace tag to hash
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*
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* Returns 31 bit hash of ns + name (so it fits in an off_t )
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*/
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static unsigned int sysfs_name_hash(const char *name, const void *ns)
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{
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unsigned long hash = init_name_hash();
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unsigned int len = strlen(name);
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while (len--)
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hash = partial_name_hash(*name++, hash);
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hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
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hash &= 0x7fffffffU;
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/* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
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if (hash < 1)
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hash += 2;
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if (hash >= INT_MAX)
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hash = INT_MAX - 1;
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return hash;
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}
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static int sysfs_name_compare(unsigned int hash, const char *name,
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const void *ns, const struct sysfs_dirent *sd)
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{
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if (hash != sd->s_hash)
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return hash - sd->s_hash;
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if (ns != sd->s_ns)
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return ns - sd->s_ns;
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return strcmp(name, sd->s_name);
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}
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static int sysfs_sd_compare(const struct sysfs_dirent *left,
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const struct sysfs_dirent *right)
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{
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return sysfs_name_compare(left->s_hash, left->s_name, left->s_ns,
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right);
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}
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/**
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* sysfs_link_sibling - link sysfs_dirent into sibling rbtree
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* @sd: sysfs_dirent of interest
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*
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* Link @sd into its sibling rbtree which starts from
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* sd->s_parent->s_dir.children.
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*
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* Locking:
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* mutex_lock(sysfs_mutex)
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*
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* RETURNS:
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* 0 on susccess -EEXIST on failure.
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*/
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static int sysfs_link_sibling(struct sysfs_dirent *sd)
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{
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struct rb_node **node = &sd->s_parent->s_dir.children.rb_node;
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struct rb_node *parent = NULL;
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if (sysfs_type(sd) == SYSFS_DIR)
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sd->s_parent->s_dir.subdirs++;
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while (*node) {
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struct sysfs_dirent *pos;
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int result;
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pos = to_sysfs_dirent(*node);
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parent = *node;
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result = sysfs_sd_compare(sd, pos);
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if (result < 0)
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node = &pos->s_rb.rb_left;
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else if (result > 0)
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node = &pos->s_rb.rb_right;
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else
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return -EEXIST;
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}
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/* add new node and rebalance the tree */
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rb_link_node(&sd->s_rb, parent, node);
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rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children);
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return 0;
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}
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/**
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* sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree
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* @sd: sysfs_dirent of interest
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*
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* Unlink @sd from its sibling rbtree which starts from
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* sd->s_parent->s_dir.children.
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*
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* Locking:
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* mutex_lock(sysfs_mutex)
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*/
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static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
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{
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if (sysfs_type(sd) == SYSFS_DIR)
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sd->s_parent->s_dir.subdirs--;
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rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
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}
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/**
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* sysfs_get_active - get an active reference to sysfs_dirent
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* @sd: sysfs_dirent to get an active reference to
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*
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* Get an active reference of @sd. This function is noop if @sd
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* is NULL.
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*
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* RETURNS:
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* Pointer to @sd on success, NULL on failure.
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*/
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struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
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{
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if (unlikely(!sd))
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return NULL;
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if (!atomic_inc_unless_negative(&sd->s_active))
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return NULL;
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if (likely(!sysfs_ignore_lockdep(sd)))
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rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
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return sd;
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}
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/**
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* sysfs_put_active - put an active reference to sysfs_dirent
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* @sd: sysfs_dirent to put an active reference to
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*
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* Put an active reference to @sd. This function is noop if @sd
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* is NULL.
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*/
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void sysfs_put_active(struct sysfs_dirent *sd)
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{
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int v;
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if (unlikely(!sd))
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return;
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if (likely(!sysfs_ignore_lockdep(sd)))
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rwsem_release(&sd->dep_map, 1, _RET_IP_);
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v = atomic_dec_return(&sd->s_active);
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if (likely(v != SD_DEACTIVATED_BIAS))
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return;
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/* atomic_dec_return() is a mb(), we'll always see the updated
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* sd->u.completion.
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*/
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complete(sd->u.completion);
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}
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/**
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* sysfs_deactivate - deactivate sysfs_dirent
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* @sd: sysfs_dirent to deactivate
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*
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* Deny new active references and drain existing ones.
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*/
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static void sysfs_deactivate(struct sysfs_dirent *sd)
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{
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DECLARE_COMPLETION_ONSTACK(wait);
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int v;
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BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED));
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if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
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return;
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sd->u.completion = (void *)&wait;
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rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
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/* atomic_add_return() is a mb(), put_active() will always see
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* the updated sd->u.completion.
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*/
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v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
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if (v != SD_DEACTIVATED_BIAS) {
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lock_contended(&sd->dep_map, _RET_IP_);
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wait_for_completion(&wait);
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}
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lock_acquired(&sd->dep_map, _RET_IP_);
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rwsem_release(&sd->dep_map, 1, _RET_IP_);
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}
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static int sysfs_alloc_ino(unsigned int *pino)
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{
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int ino, rc;
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retry:
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spin_lock(&sysfs_ino_lock);
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rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
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spin_unlock(&sysfs_ino_lock);
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if (rc == -EAGAIN) {
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if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
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goto retry;
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rc = -ENOMEM;
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}
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*pino = ino;
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return rc;
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}
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static void sysfs_free_ino(unsigned int ino)
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{
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spin_lock(&sysfs_ino_lock);
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ida_remove(&sysfs_ino_ida, ino);
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spin_unlock(&sysfs_ino_lock);
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}
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void release_sysfs_dirent(struct sysfs_dirent *sd)
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{
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struct sysfs_dirent *parent_sd;
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repeat:
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/* Moving/renaming is always done while holding reference.
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* sd->s_parent won't change beneath us.
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*/
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parent_sd = sd->s_parent;
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WARN(!(sd->s_flags & SYSFS_FLAG_REMOVED),
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"sysfs: free using entry: %s/%s\n",
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parent_sd ? parent_sd->s_name : "", sd->s_name);
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if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
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sysfs_put(sd->s_symlink.target_sd);
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if (sysfs_type(sd) & SYSFS_COPY_NAME)
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kfree(sd->s_name);
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if (sd->s_iattr && sd->s_iattr->ia_secdata)
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security_release_secctx(sd->s_iattr->ia_secdata,
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sd->s_iattr->ia_secdata_len);
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kfree(sd->s_iattr);
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sysfs_free_ino(sd->s_ino);
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kmem_cache_free(sysfs_dir_cachep, sd);
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sd = parent_sd;
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if (sd && atomic_dec_and_test(&sd->s_count))
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goto repeat;
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}
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static int sysfs_dentry_delete(const struct dentry *dentry)
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{
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struct sysfs_dirent *sd = dentry->d_fsdata;
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return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED));
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}
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static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
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{
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struct sysfs_dirent *sd;
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int type;
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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sd = dentry->d_fsdata;
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mutex_lock(&sysfs_mutex);
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/* The sysfs dirent has been deleted */
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if (sd->s_flags & SYSFS_FLAG_REMOVED)
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goto out_bad;
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/* The sysfs dirent has been moved? */
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if (dentry->d_parent->d_fsdata != sd->s_parent)
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goto out_bad;
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/* The sysfs dirent has been renamed */
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if (strcmp(dentry->d_name.name, sd->s_name) != 0)
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goto out_bad;
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/* The sysfs dirent has been moved to a different namespace */
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type = KOBJ_NS_TYPE_NONE;
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if (sd->s_parent) {
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type = sysfs_ns_type(sd->s_parent);
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if (type != KOBJ_NS_TYPE_NONE &&
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sysfs_info(dentry->d_sb)->ns[type] != sd->s_ns)
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goto out_bad;
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}
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mutex_unlock(&sysfs_mutex);
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out_valid:
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return 1;
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out_bad:
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/* Remove the dentry from the dcache hashes.
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* If this is a deleted dentry we use d_drop instead of d_delete
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* so sysfs doesn't need to cope with negative dentries.
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*
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* If this is a dentry that has simply been renamed we
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* use d_drop to remove it from the dcache lookup on its
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* old parent. If this dentry persists later when a lookup
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* is performed at its new name the dentry will be readded
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* to the dcache hashes.
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*/
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mutex_unlock(&sysfs_mutex);
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/* If we have submounts we must allow the vfs caches
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* to lie about the state of the filesystem to prevent
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* leaks and other nasty things.
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*/
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if (check_submounts_and_drop(dentry) != 0)
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goto out_valid;
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return 0;
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}
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static void sysfs_dentry_release(struct dentry *dentry)
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{
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sysfs_put(dentry->d_fsdata);
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}
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const struct dentry_operations sysfs_dentry_ops = {
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.d_revalidate = sysfs_dentry_revalidate,
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.d_delete = sysfs_dentry_delete,
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.d_release = sysfs_dentry_release,
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};
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struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
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{
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char *dup_name = NULL;
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struct sysfs_dirent *sd;
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if (type & SYSFS_COPY_NAME) {
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name = dup_name = kstrdup(name, GFP_KERNEL);
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if (!name)
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return NULL;
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}
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sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
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if (!sd)
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goto err_out1;
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if (sysfs_alloc_ino(&sd->s_ino))
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goto err_out2;
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atomic_set(&sd->s_count, 1);
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atomic_set(&sd->s_active, 0);
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sd->s_name = name;
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sd->s_mode = mode;
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sd->s_flags = type | SYSFS_FLAG_REMOVED;
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return sd;
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err_out2:
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kmem_cache_free(sysfs_dir_cachep, sd);
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err_out1:
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kfree(dup_name);
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return NULL;
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}
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/**
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* sysfs_addrm_start - prepare for sysfs_dirent add/remove
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* @acxt: pointer to sysfs_addrm_cxt to be used
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*
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* This function is called when the caller is about to add or remove
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* sysfs_dirent. This function acquires sysfs_mutex. @acxt is used
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* to keep and pass context to other addrm functions.
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*
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* LOCKING:
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* Kernel thread context (may sleep). sysfs_mutex is locked on
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* return.
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*/
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void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt)
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__acquires(sysfs_mutex)
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{
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memset(acxt, 0, sizeof(*acxt));
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mutex_lock(&sysfs_mutex);
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}
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/**
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* __sysfs_add_one - add sysfs_dirent to parent without warning
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* @acxt: addrm context to use
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* @sd: sysfs_dirent to be added
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* @parent_sd: the parent sysfs_dirent to add @sd to
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*
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* Get @parent_sd and set @sd->s_parent to it and increment nlink of
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* the parent inode if @sd is a directory and link into the children
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* list of the parent.
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*
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* This function should be called between calls to
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* sysfs_addrm_start() and sysfs_addrm_finish() and should be
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* passed the same @acxt as passed to sysfs_addrm_start().
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*
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* LOCKING:
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* Determined by sysfs_addrm_start().
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*
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* RETURNS:
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* 0 on success, -EEXIST if entry with the given name already
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* exists.
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*/
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int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd,
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struct sysfs_dirent *parent_sd)
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{
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struct sysfs_inode_attrs *ps_iattr;
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int ret;
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if (!!sysfs_ns_type(parent_sd) != !!sd->s_ns) {
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WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
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sysfs_ns_type(parent_sd) ? "required" : "invalid",
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parent_sd->s_name, sd->s_name);
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return -EINVAL;
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}
|
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sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns);
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sd->s_parent = sysfs_get(parent_sd);
|
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|
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ret = sysfs_link_sibling(sd);
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if (ret)
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return ret;
|
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|
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/* Update timestamps on the parent */
|
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ps_iattr = parent_sd->s_iattr;
|
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if (ps_iattr) {
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struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
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ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
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}
|
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|
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/* Mark the entry added into directory tree */
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sd->s_flags &= ~SYSFS_FLAG_REMOVED;
|
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|
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return 0;
|
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}
|
|
|
|
/**
|
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* sysfs_pathname - return full path to sysfs dirent
|
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* @sd: sysfs_dirent whose path we want
|
|
* @path: caller allocated buffer of size PATH_MAX
|
|
*
|
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* Gives the name "/" to the sysfs_root entry; any path returned
|
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* is relative to wherever sysfs is mounted.
|
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*/
|
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static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
|
|
{
|
|
if (sd->s_parent) {
|
|
sysfs_pathname(sd->s_parent, path);
|
|
strlcat(path, "/", PATH_MAX);
|
|
}
|
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strlcat(path, sd->s_name, PATH_MAX);
|
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return path;
|
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}
|
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|
|
void sysfs_warn_dup(struct sysfs_dirent *parent, const char *name)
|
|
{
|
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char *path;
|
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|
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path = kzalloc(PATH_MAX, GFP_KERNEL);
|
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if (path) {
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sysfs_pathname(parent, path);
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strlcat(path, "/", PATH_MAX);
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strlcat(path, name, PATH_MAX);
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}
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|
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WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s'\n",
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path ? path : name);
|
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|
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kfree(path);
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}
|
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|
|
/**
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* sysfs_add_one - add sysfs_dirent to parent
|
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* @acxt: addrm context to use
|
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* @sd: sysfs_dirent to be added
|
|
* @parent_sd: the parent sysfs_dirent to add @sd to
|
|
*
|
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* Get @parent_sd and set @sd->s_parent to it and increment nlink of
|
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* the parent inode if @sd is a directory and link into the children
|
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* list of the parent.
|
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*
|
|
* This function should be called between calls to
|
|
* sysfs_addrm_start() and sysfs_addrm_finish() and should be
|
|
* passed the same @acxt as passed to sysfs_addrm_start().
|
|
*
|
|
* LOCKING:
|
|
* Determined by sysfs_addrm_start().
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -EEXIST if entry with the given name already
|
|
* exists.
|
|
*/
|
|
int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd,
|
|
struct sysfs_dirent *parent_sd)
|
|
{
|
|
int ret;
|
|
|
|
ret = __sysfs_add_one(acxt, sd, parent_sd);
|
|
|
|
if (ret == -EEXIST)
|
|
sysfs_warn_dup(parent_sd, sd->s_name);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* sysfs_remove_one - remove sysfs_dirent from parent
|
|
* @acxt: addrm context to use
|
|
* @sd: sysfs_dirent to be removed
|
|
*
|
|
* Mark @sd removed and drop nlink of parent inode if @sd is a
|
|
* directory. @sd is unlinked from the children list.
|
|
*
|
|
* This function should be called between calls to
|
|
* sysfs_addrm_start() and sysfs_addrm_finish() and should be
|
|
* passed the same @acxt as passed to sysfs_addrm_start().
|
|
*
|
|
* LOCKING:
|
|
* Determined by sysfs_addrm_start().
|
|
*/
|
|
static void sysfs_remove_one(struct sysfs_addrm_cxt *acxt,
|
|
struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_inode_attrs *ps_iattr;
|
|
|
|
/*
|
|
* Removal can be called multiple times on the same node. Only the
|
|
* first invocation is effective and puts the base ref.
|
|
*/
|
|
if (sd->s_flags & SYSFS_FLAG_REMOVED)
|
|
return;
|
|
|
|
sysfs_unlink_sibling(sd);
|
|
|
|
/* Update timestamps on the parent */
|
|
ps_iattr = sd->s_parent->s_iattr;
|
|
if (ps_iattr) {
|
|
struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
|
|
ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
|
|
}
|
|
|
|
sd->s_flags |= SYSFS_FLAG_REMOVED;
|
|
sd->u.removed_list = acxt->removed;
|
|
acxt->removed = sd;
|
|
}
|
|
|
|
/**
|
|
* sysfs_addrm_finish - finish up sysfs_dirent add/remove
|
|
* @acxt: addrm context to finish up
|
|
*
|
|
* Finish up sysfs_dirent add/remove. Resources acquired by
|
|
* sysfs_addrm_start() are released and removed sysfs_dirents are
|
|
* cleaned up.
|
|
*
|
|
* LOCKING:
|
|
* sysfs_mutex is released.
|
|
*/
|
|
void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
|
|
__releases(sysfs_mutex)
|
|
{
|
|
/* release resources acquired by sysfs_addrm_start() */
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
/* kill removed sysfs_dirents */
|
|
while (acxt->removed) {
|
|
struct sysfs_dirent *sd = acxt->removed;
|
|
|
|
acxt->removed = sd->u.removed_list;
|
|
|
|
sysfs_deactivate(sd);
|
|
sysfs_unmap_bin_file(sd);
|
|
sysfs_put(sd);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* sysfs_find_dirent - find sysfs_dirent with the given name
|
|
* @parent_sd: sysfs_dirent to search under
|
|
* @name: name to look for
|
|
* @ns: the namespace tag to use
|
|
*
|
|
* Look for sysfs_dirent with name @name under @parent_sd.
|
|
*
|
|
* LOCKING:
|
|
* mutex_lock(sysfs_mutex)
|
|
*
|
|
* RETURNS:
|
|
* Pointer to sysfs_dirent if found, NULL if not.
|
|
*/
|
|
struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
|
|
const unsigned char *name,
|
|
const void *ns)
|
|
{
|
|
struct rb_node *node = parent_sd->s_dir.children.rb_node;
|
|
unsigned int hash;
|
|
|
|
if (!!sysfs_ns_type(parent_sd) != !!ns) {
|
|
WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
|
|
sysfs_ns_type(parent_sd) ? "required" : "invalid",
|
|
parent_sd->s_name, name);
|
|
return NULL;
|
|
}
|
|
|
|
hash = sysfs_name_hash(name, ns);
|
|
while (node) {
|
|
struct sysfs_dirent *sd;
|
|
int result;
|
|
|
|
sd = to_sysfs_dirent(node);
|
|
result = sysfs_name_compare(hash, name, ns, sd);
|
|
if (result < 0)
|
|
node = node->rb_left;
|
|
else if (result > 0)
|
|
node = node->rb_right;
|
|
else
|
|
return sd;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* sysfs_get_dirent_ns - find and get sysfs_dirent with the given name
|
|
* @parent_sd: sysfs_dirent to search under
|
|
* @name: name to look for
|
|
* @ns: the namespace tag to use
|
|
*
|
|
* Look for sysfs_dirent with name @name under @parent_sd and get
|
|
* it if found.
|
|
*
|
|
* LOCKING:
|
|
* Kernel thread context (may sleep). Grabs sysfs_mutex.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to sysfs_dirent if found, NULL if not.
|
|
*/
|
|
struct sysfs_dirent *sysfs_get_dirent_ns(struct sysfs_dirent *parent_sd,
|
|
const unsigned char *name,
|
|
const void *ns)
|
|
{
|
|
struct sysfs_dirent *sd;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
sd = sysfs_find_dirent(parent_sd, name, ns);
|
|
sysfs_get(sd);
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
return sd;
|
|
}
|
|
EXPORT_SYMBOL_GPL(sysfs_get_dirent_ns);
|
|
|
|
static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
|
|
enum kobj_ns_type type,
|
|
const char *name, const void *ns,
|
|
struct sysfs_dirent **p_sd)
|
|
{
|
|
umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
|
|
struct sysfs_addrm_cxt acxt;
|
|
struct sysfs_dirent *sd;
|
|
int rc;
|
|
|
|
/* allocate */
|
|
sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
|
|
if (!sd)
|
|
return -ENOMEM;
|
|
|
|
sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
|
|
sd->s_ns = ns;
|
|
sd->s_dir.kobj = kobj;
|
|
|
|
/* link in */
|
|
sysfs_addrm_start(&acxt);
|
|
rc = sysfs_add_one(&acxt, sd, parent_sd);
|
|
sysfs_addrm_finish(&acxt);
|
|
|
|
if (rc == 0)
|
|
*p_sd = sd;
|
|
else
|
|
sysfs_put(sd);
|
|
|
|
return rc;
|
|
}
|
|
|
|
int sysfs_create_subdir(struct kobject *kobj, const char *name,
|
|
struct sysfs_dirent **p_sd)
|
|
{
|
|
return create_dir(kobj, kobj->sd,
|
|
KOBJ_NS_TYPE_NONE, name, NULL, p_sd);
|
|
}
|
|
|
|
/**
|
|
* sysfs_read_ns_type: return associated ns_type
|
|
* @kobj: the kobject being queried
|
|
*
|
|
* Each kobject can be tagged with exactly one namespace type
|
|
* (i.e. network or user). Return the ns_type associated with
|
|
* this object if any
|
|
*/
|
|
static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
|
|
{
|
|
const struct kobj_ns_type_operations *ops;
|
|
enum kobj_ns_type type;
|
|
|
|
ops = kobj_child_ns_ops(kobj);
|
|
if (!ops)
|
|
return KOBJ_NS_TYPE_NONE;
|
|
|
|
type = ops->type;
|
|
BUG_ON(type <= KOBJ_NS_TYPE_NONE);
|
|
BUG_ON(type >= KOBJ_NS_TYPES);
|
|
BUG_ON(!kobj_ns_type_registered(type));
|
|
|
|
return type;
|
|
}
|
|
|
|
/**
|
|
* sysfs_create_dir_ns - create a directory for an object with a namespace tag
|
|
* @kobj: object we're creating directory for
|
|
* @ns: the namespace tag to use
|
|
*/
|
|
int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
|
|
{
|
|
enum kobj_ns_type type;
|
|
struct sysfs_dirent *parent_sd, *sd;
|
|
int error = 0;
|
|
|
|
BUG_ON(!kobj);
|
|
|
|
if (kobj->parent)
|
|
parent_sd = kobj->parent->sd;
|
|
else
|
|
parent_sd = &sysfs_root;
|
|
|
|
if (!parent_sd)
|
|
return -ENOENT;
|
|
|
|
type = sysfs_read_ns_type(kobj);
|
|
|
|
error = create_dir(kobj, parent_sd, type, kobject_name(kobj), ns, &sd);
|
|
if (!error)
|
|
kobj->sd = sd;
|
|
return error;
|
|
}
|
|
|
|
static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
|
|
unsigned int flags)
|
|
{
|
|
struct dentry *ret = NULL;
|
|
struct dentry *parent = dentry->d_parent;
|
|
struct sysfs_dirent *parent_sd = parent->d_fsdata;
|
|
struct sysfs_dirent *sd;
|
|
struct inode *inode;
|
|
enum kobj_ns_type type;
|
|
const void *ns;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
type = sysfs_ns_type(parent_sd);
|
|
ns = sysfs_info(dir->i_sb)->ns[type];
|
|
|
|
sd = sysfs_find_dirent(parent_sd, dentry->d_name.name, ns);
|
|
|
|
/* no such entry */
|
|
if (!sd) {
|
|
ret = ERR_PTR(-ENOENT);
|
|
goto out_unlock;
|
|
}
|
|
dentry->d_fsdata = sysfs_get(sd);
|
|
|
|
/* attach dentry and inode */
|
|
inode = sysfs_get_inode(dir->i_sb, sd);
|
|
if (!inode) {
|
|
ret = ERR_PTR(-ENOMEM);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* instantiate and hash dentry */
|
|
ret = d_materialise_unique(dentry, inode);
|
|
out_unlock:
|
|
mutex_unlock(&sysfs_mutex);
|
|
return ret;
|
|
}
|
|
|
|
const struct inode_operations sysfs_dir_inode_operations = {
|
|
.lookup = sysfs_lookup,
|
|
.permission = sysfs_permission,
|
|
.setattr = sysfs_setattr,
|
|
.getattr = sysfs_getattr,
|
|
.setxattr = sysfs_setxattr,
|
|
};
|
|
|
|
static struct sysfs_dirent *sysfs_leftmost_descendant(struct sysfs_dirent *pos)
|
|
{
|
|
struct sysfs_dirent *last;
|
|
|
|
while (true) {
|
|
struct rb_node *rbn;
|
|
|
|
last = pos;
|
|
|
|
if (sysfs_type(pos) != SYSFS_DIR)
|
|
break;
|
|
|
|
rbn = rb_first(&pos->s_dir.children);
|
|
if (!rbn)
|
|
break;
|
|
|
|
pos = to_sysfs_dirent(rbn);
|
|
}
|
|
|
|
return last;
|
|
}
|
|
|
|
/**
|
|
* sysfs_next_descendant_post - find the next descendant for post-order walk
|
|
* @pos: the current position (%NULL to initiate traversal)
|
|
* @root: sysfs_dirent whose descendants to walk
|
|
*
|
|
* Find the next descendant to visit for post-order traversal of @root's
|
|
* descendants. @root is included in the iteration and the last node to be
|
|
* visited.
|
|
*/
|
|
static struct sysfs_dirent *sysfs_next_descendant_post(struct sysfs_dirent *pos,
|
|
struct sysfs_dirent *root)
|
|
{
|
|
struct rb_node *rbn;
|
|
|
|
lockdep_assert_held(&sysfs_mutex);
|
|
|
|
/* if first iteration, visit leftmost descendant which may be root */
|
|
if (!pos)
|
|
return sysfs_leftmost_descendant(root);
|
|
|
|
/* if we visited @root, we're done */
|
|
if (pos == root)
|
|
return NULL;
|
|
|
|
/* if there's an unvisited sibling, visit its leftmost descendant */
|
|
rbn = rb_next(&pos->s_rb);
|
|
if (rbn)
|
|
return sysfs_leftmost_descendant(to_sysfs_dirent(rbn));
|
|
|
|
/* no sibling left, visit parent */
|
|
return pos->s_parent;
|
|
}
|
|
|
|
static void __sysfs_remove(struct sysfs_addrm_cxt *acxt,
|
|
struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_dirent *pos, *next;
|
|
|
|
if (!sd)
|
|
return;
|
|
|
|
pr_debug("sysfs %s: removing\n", sd->s_name);
|
|
|
|
next = NULL;
|
|
do {
|
|
pos = next;
|
|
next = sysfs_next_descendant_post(pos, sd);
|
|
if (pos)
|
|
sysfs_remove_one(acxt, pos);
|
|
} while (next);
|
|
}
|
|
|
|
/**
|
|
* sysfs_remove - remove a sysfs_dirent recursively
|
|
* @sd: the sysfs_dirent to remove
|
|
*
|
|
* Remove @sd along with all its subdirectories and files.
|
|
*/
|
|
void sysfs_remove(struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_addrm_cxt acxt;
|
|
|
|
sysfs_addrm_start(&acxt);
|
|
__sysfs_remove(&acxt, sd);
|
|
sysfs_addrm_finish(&acxt);
|
|
}
|
|
|
|
/**
|
|
* sysfs_hash_and_remove - find a sysfs_dirent by name and remove it
|
|
* @dir_sd: parent of the target
|
|
* @name: name of the sysfs_dirent to remove
|
|
* @ns: namespace tag of the sysfs_dirent to remove
|
|
*
|
|
* Look for the sysfs_dirent with @name and @ns under @dir_sd and remove
|
|
* it. Returns 0 on success, -ENOENT if such entry doesn't exist.
|
|
*/
|
|
int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name,
|
|
const void *ns)
|
|
{
|
|
struct sysfs_addrm_cxt acxt;
|
|
struct sysfs_dirent *sd;
|
|
|
|
if (!dir_sd) {
|
|
WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n",
|
|
name);
|
|
return -ENOENT;
|
|
}
|
|
|
|
sysfs_addrm_start(&acxt);
|
|
|
|
sd = sysfs_find_dirent(dir_sd, name, ns);
|
|
if (sd)
|
|
__sysfs_remove(&acxt, sd);
|
|
|
|
sysfs_addrm_finish(&acxt);
|
|
|
|
if (sd)
|
|
return 0;
|
|
else
|
|
return -ENOENT;
|
|
}
|
|
|
|
/**
|
|
* sysfs_remove_dir - remove an object's directory.
|
|
* @kobj: object.
|
|
*
|
|
* The only thing special about this is that we remove any files in
|
|
* the directory before we remove the directory, and we've inlined
|
|
* what used to be sysfs_rmdir() below, instead of calling separately.
|
|
*/
|
|
void sysfs_remove_dir(struct kobject *kobj)
|
|
{
|
|
struct sysfs_dirent *sd = kobj->sd;
|
|
|
|
/*
|
|
* In general, kboject owner is responsible for ensuring removal
|
|
* doesn't race with other operations and sysfs doesn't provide any
|
|
* protection; however, when @kobj is used as a symlink target, the
|
|
* symlinking entity usually doesn't own @kobj and thus has no
|
|
* control over removal. @kobj->sd may be removed anytime and
|
|
* symlink code may end up dereferencing an already freed sd.
|
|
*
|
|
* sysfs_symlink_target_lock synchronizes @kobj->sd disassociation
|
|
* against symlink operations so that symlink code can safely
|
|
* dereference @kobj->sd.
|
|
*/
|
|
spin_lock(&sysfs_symlink_target_lock);
|
|
kobj->sd = NULL;
|
|
spin_unlock(&sysfs_symlink_target_lock);
|
|
|
|
if (sd) {
|
|
WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR);
|
|
sysfs_remove(sd);
|
|
}
|
|
}
|
|
|
|
int sysfs_rename(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent_sd,
|
|
const char *new_name, const void *new_ns)
|
|
{
|
|
int error;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
error = 0;
|
|
if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
|
|
(strcmp(sd->s_name, new_name) == 0))
|
|
goto out; /* nothing to rename */
|
|
|
|
error = -EEXIST;
|
|
if (sysfs_find_dirent(new_parent_sd, new_name, new_ns))
|
|
goto out;
|
|
|
|
/* rename sysfs_dirent */
|
|
if (strcmp(sd->s_name, new_name) != 0) {
|
|
error = -ENOMEM;
|
|
new_name = kstrdup(new_name, GFP_KERNEL);
|
|
if (!new_name)
|
|
goto out;
|
|
|
|
kfree(sd->s_name);
|
|
sd->s_name = new_name;
|
|
}
|
|
|
|
/*
|
|
* Move to the appropriate place in the appropriate directories rbtree.
|
|
*/
|
|
sysfs_unlink_sibling(sd);
|
|
sysfs_get(new_parent_sd);
|
|
sysfs_put(sd->s_parent);
|
|
sd->s_ns = new_ns;
|
|
sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns);
|
|
sd->s_parent = new_parent_sd;
|
|
sysfs_link_sibling(sd);
|
|
|
|
error = 0;
|
|
out:
|
|
mutex_unlock(&sysfs_mutex);
|
|
return error;
|
|
}
|
|
|
|
int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
|
|
const void *new_ns)
|
|
{
|
|
struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
|
|
|
|
return sysfs_rename(kobj->sd, parent_sd, new_name, new_ns);
|
|
}
|
|
|
|
int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
|
|
const void *new_ns)
|
|
{
|
|
struct sysfs_dirent *sd = kobj->sd;
|
|
struct sysfs_dirent *new_parent_sd;
|
|
|
|
BUG_ON(!sd->s_parent);
|
|
new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
|
|
new_parent_kobj->sd : &sysfs_root;
|
|
|
|
return sysfs_rename(sd, new_parent_sd, sd->s_name, new_ns);
|
|
}
|
|
|
|
/* Relationship between s_mode and the DT_xxx types */
|
|
static inline unsigned char dt_type(struct sysfs_dirent *sd)
|
|
{
|
|
return (sd->s_mode >> 12) & 15;
|
|
}
|
|
|
|
static int sysfs_dir_release(struct inode *inode, struct file *filp)
|
|
{
|
|
sysfs_put(filp->private_data);
|
|
return 0;
|
|
}
|
|
|
|
static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
|
|
struct sysfs_dirent *parent_sd, loff_t hash, struct sysfs_dirent *pos)
|
|
{
|
|
if (pos) {
|
|
int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
|
|
pos->s_parent == parent_sd &&
|
|
hash == pos->s_hash;
|
|
sysfs_put(pos);
|
|
if (!valid)
|
|
pos = NULL;
|
|
}
|
|
if (!pos && (hash > 1) && (hash < INT_MAX)) {
|
|
struct rb_node *node = parent_sd->s_dir.children.rb_node;
|
|
while (node) {
|
|
pos = to_sysfs_dirent(node);
|
|
|
|
if (hash < pos->s_hash)
|
|
node = node->rb_left;
|
|
else if (hash > pos->s_hash)
|
|
node = node->rb_right;
|
|
else
|
|
break;
|
|
}
|
|
}
|
|
/* Skip over entries in the wrong namespace */
|
|
while (pos && pos->s_ns != ns) {
|
|
struct rb_node *node = rb_next(&pos->s_rb);
|
|
if (!node)
|
|
pos = NULL;
|
|
else
|
|
pos = to_sysfs_dirent(node);
|
|
}
|
|
return pos;
|
|
}
|
|
|
|
static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
|
|
struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
|
|
{
|
|
pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
|
|
if (pos)
|
|
do {
|
|
struct rb_node *node = rb_next(&pos->s_rb);
|
|
if (!node)
|
|
pos = NULL;
|
|
else
|
|
pos = to_sysfs_dirent(node);
|
|
} while (pos && pos->s_ns != ns);
|
|
return pos;
|
|
}
|
|
|
|
static int sysfs_readdir(struct file *file, struct dir_context *ctx)
|
|
{
|
|
struct dentry *dentry = file->f_path.dentry;
|
|
struct sysfs_dirent *parent_sd = dentry->d_fsdata;
|
|
struct sysfs_dirent *pos = file->private_data;
|
|
enum kobj_ns_type type;
|
|
const void *ns;
|
|
|
|
type = sysfs_ns_type(parent_sd);
|
|
ns = sysfs_info(dentry->d_sb)->ns[type];
|
|
|
|
if (!dir_emit_dots(file, ctx))
|
|
return 0;
|
|
mutex_lock(&sysfs_mutex);
|
|
for (pos = sysfs_dir_pos(ns, parent_sd, ctx->pos, pos);
|
|
pos;
|
|
pos = sysfs_dir_next_pos(ns, parent_sd, ctx->pos, pos)) {
|
|
const char *name = pos->s_name;
|
|
unsigned int type = dt_type(pos);
|
|
int len = strlen(name);
|
|
ino_t ino = pos->s_ino;
|
|
ctx->pos = pos->s_hash;
|
|
file->private_data = sysfs_get(pos);
|
|
|
|
mutex_unlock(&sysfs_mutex);
|
|
if (!dir_emit(ctx, name, len, ino, type))
|
|
return 0;
|
|
mutex_lock(&sysfs_mutex);
|
|
}
|
|
mutex_unlock(&sysfs_mutex);
|
|
file->private_data = NULL;
|
|
ctx->pos = INT_MAX;
|
|
return 0;
|
|
}
|
|
|
|
static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
loff_t ret;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
ret = generic_file_llseek(file, offset, whence);
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
const struct file_operations sysfs_dir_operations = {
|
|
.read = generic_read_dir,
|
|
.iterate = sysfs_readdir,
|
|
.release = sysfs_dir_release,
|
|
.llseek = sysfs_dir_llseek,
|
|
};
|