diff options
Diffstat (limited to 'fs/sysfs/dir.c')
-rw-r--r-- | fs/sysfs/dir.c | 350 |
1 files changed, 222 insertions, 128 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 4d83cedb9fcb..5e73d6626e50 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -26,21 +26,21 @@ #include "sysfs.h" DEFINE_MUTEX(sysfs_mutex); -DEFINE_SPINLOCK(sysfs_assoc_lock); +DEFINE_SPINLOCK(sysfs_symlink_target_lock); -#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb); +#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb) static DEFINE_SPINLOCK(sysfs_ino_lock); static DEFINE_IDA(sysfs_ino_ida); /** * sysfs_name_hash - * @ns: Namespace tag to hash * @name: Null terminated string to hash + * @ns: Namespace tag to hash * * Returns 31 bit hash of ns + name (so it fits in an off_t ) */ -static unsigned int sysfs_name_hash(const void *ns, const char *name) +static unsigned int sysfs_name_hash(const char *name, const void *ns) { unsigned long hash = init_name_hash(); unsigned int len = strlen(name); @@ -56,8 +56,8 @@ static unsigned int sysfs_name_hash(const void *ns, const char *name) return hash; } -static int sysfs_name_compare(unsigned int hash, const void *ns, - const char *name, const struct sysfs_dirent *sd) +static int sysfs_name_compare(unsigned int hash, const char *name, + const void *ns, const struct sysfs_dirent *sd) { if (hash != sd->s_hash) return hash - sd->s_hash; @@ -69,7 +69,7 @@ static int sysfs_name_compare(unsigned int hash, const void *ns, static int sysfs_sd_compare(const struct sysfs_dirent *left, const struct sysfs_dirent *right) { - return sysfs_name_compare(left->s_hash, left->s_ns, left->s_name, + return sysfs_name_compare(left->s_hash, left->s_name, left->s_ns, right); } @@ -132,24 +132,6 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd) rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children); } -#ifdef CONFIG_DEBUG_LOCK_ALLOC - -/* Test for attributes that want to ignore lockdep for read-locking */ -static bool ignore_lockdep(struct sysfs_dirent *sd) -{ - return sysfs_type(sd) == SYSFS_KOBJ_ATTR && - sd->s_attr.attr->ignore_lockdep; -} - -#else - -static inline bool ignore_lockdep(struct sysfs_dirent *sd) -{ - return true; -} - -#endif - /** * sysfs_get_active - get an active reference to sysfs_dirent * @sd: sysfs_dirent to get an active reference to @@ -168,7 +150,7 @@ struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) if (!atomic_inc_unless_negative(&sd->s_active)) return NULL; - if (likely(!ignore_lockdep(sd))) + if (likely(!sysfs_ignore_lockdep(sd))) rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_); return sd; } @@ -187,7 +169,7 @@ void sysfs_put_active(struct sysfs_dirent *sd) if (unlikely(!sd)) return; - if (likely(!ignore_lockdep(sd))) + if (likely(!sysfs_ignore_lockdep(sd))) rwsem_release(&sd->dep_map, 1, _RET_IP_); v = atomic_dec_return(&sd->s_active); if (likely(v != SD_DEACTIVATED_BIAS)) @@ -400,22 +382,19 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) /** * sysfs_addrm_start - prepare for sysfs_dirent add/remove * @acxt: pointer to sysfs_addrm_cxt to be used - * @parent_sd: parent sysfs_dirent * - * This function is called when the caller is about to add or - * remove sysfs_dirent under @parent_sd. This function acquires - * sysfs_mutex. @acxt is used to keep and pass context to - * other addrm functions. + * This function is called when the caller is about to add or remove + * sysfs_dirent. This function acquires sysfs_mutex. @acxt is used + * to keep and pass context to other addrm functions. * * LOCKING: * Kernel thread context (may sleep). sysfs_mutex is locked on * return. */ -void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, - struct sysfs_dirent *parent_sd) +void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt) + __acquires(sysfs_mutex) { memset(acxt, 0, sizeof(*acxt)); - acxt->parent_sd = parent_sd; mutex_lock(&sysfs_mutex); } @@ -424,10 +403,11 @@ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, * __sysfs_add_one - add sysfs_dirent to parent without warning * @acxt: addrm context to use * @sd: sysfs_dirent to be added + * @parent_sd: the parent sysfs_dirent to add @sd to * - * Get @acxt->parent_sd and set sd->s_parent to it and increment - * nlink of parent inode if @sd is a directory and link into the - * children list of the parent. + * Get @parent_sd and set @sd->s_parent to it and increment nlink of + * the parent inode if @sd is a directory and link into the children + * list of the parent. * * This function should be called between calls to * sysfs_addrm_start() and sysfs_addrm_finish() and should be @@ -440,27 +420,28 @@ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, * 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) +int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd, + struct sysfs_dirent *parent_sd) { struct sysfs_inode_attrs *ps_iattr; int ret; - if (!!sysfs_ns_type(acxt->parent_sd) != !!sd->s_ns) { + if (!!sysfs_ns_type(parent_sd) != !!sd->s_ns) { WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", - sysfs_ns_type(acxt->parent_sd) ? "required" : "invalid", - acxt->parent_sd->s_name, sd->s_name); + sysfs_ns_type(parent_sd) ? "required" : "invalid", + parent_sd->s_name, sd->s_name); return -EINVAL; } - sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name); - sd->s_parent = sysfs_get(acxt->parent_sd); + sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns); + sd->s_parent = sysfs_get(parent_sd); ret = sysfs_link_sibling(sd); if (ret) return ret; /* Update timestamps on the parent */ - ps_iattr = acxt->parent_sd->s_iattr; + ps_iattr = parent_sd->s_iattr; if (ps_iattr) { struct iattr *ps_iattrs = &ps_iattr->ia_iattr; ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; @@ -490,14 +471,32 @@ static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) return path; } +void sysfs_warn_dup(struct sysfs_dirent *parent, const char *name) +{ + char *path; + + path = kzalloc(PATH_MAX, GFP_KERNEL); + if (path) { + sysfs_pathname(parent, path); + strlcat(path, "/", PATH_MAX); + strlcat(path, name, PATH_MAX); + } + + WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s'\n", + path ? path : name); + + kfree(path); +} + /** * sysfs_add_one - add sysfs_dirent to parent * @acxt: addrm context to use * @sd: sysfs_dirent to be added + * @parent_sd: the parent sysfs_dirent to add @sd to * - * Get @acxt->parent_sd and set sd->s_parent to it and increment - * nlink of parent inode if @sd is a directory and link into the - * children list of the parent. + * Get @parent_sd and set @sd->s_parent to it and increment nlink of + * the parent inode if @sd is a directory and link into the children + * list of the parent. * * This function should be called between calls to * sysfs_addrm_start() and sysfs_addrm_finish() and should be @@ -510,23 +509,15 @@ static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) * 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) +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); - if (ret == -EEXIST) { - char *path = kzalloc(PATH_MAX, GFP_KERNEL); - WARN(1, KERN_WARNING - "sysfs: cannot create duplicate filename '%s'\n", - (path == NULL) ? sd->s_name - : (sysfs_pathname(acxt->parent_sd, path), - strlcat(path, "/", PATH_MAX), - strlcat(path, sd->s_name, PATH_MAX), - path)); - kfree(path); - } + ret = __sysfs_add_one(acxt, sd, parent_sd); + if (ret == -EEXIST) + sysfs_warn_dup(parent_sd, sd->s_name); return ret; } @@ -545,16 +536,22 @@ int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) * LOCKING: * Determined by sysfs_addrm_start(). */ -void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) +static void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, + struct sysfs_dirent *sd) { struct sysfs_inode_attrs *ps_iattr; - BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED); + /* + * 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 = acxt->parent_sd->s_iattr; + 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; @@ -577,6 +574,7 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) * 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); @@ -588,7 +586,7 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) acxt->removed = sd->u.removed_list; sysfs_deactivate(sd); - unmap_bin_file(sd); + sysfs_unmap_bin_file(sd); sysfs_put(sd); } } @@ -597,6 +595,7 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) * 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. * @@ -607,8 +606,8 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) * Pointer to sysfs_dirent if found, NULL if not. */ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, - const void *ns, - const unsigned char *name) + const unsigned char *name, + const void *ns) { struct rb_node *node = parent_sd->s_dir.children.rb_node; unsigned int hash; @@ -620,13 +619,13 @@ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, return NULL; } - hash = sysfs_name_hash(ns, name); + hash = sysfs_name_hash(name, ns); while (node) { struct sysfs_dirent *sd; int result; sd = to_sysfs_dirent(node); - result = sysfs_name_compare(hash, ns, name, sd); + result = sysfs_name_compare(hash, name, ns, sd); if (result < 0) node = node->rb_left; else if (result > 0) @@ -638,9 +637,10 @@ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, } /** - * sysfs_get_dirent - find and get sysfs_dirent with the given name + * 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. @@ -651,24 +651,25 @@ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, * RETURNS: * Pointer to sysfs_dirent if found, NULL if not. */ -struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, - const void *ns, - const unsigned char *name) +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, ns, name); + sd = sysfs_find_dirent(parent_sd, name, ns); sysfs_get(sd); mutex_unlock(&sysfs_mutex); return sd; } -EXPORT_SYMBOL_GPL(sysfs_get_dirent); +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 void *ns, const char *name, - struct sysfs_dirent **p_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; @@ -685,8 +686,8 @@ static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, sd->s_dir.kobj = kobj; /* link in */ - sysfs_addrm_start(&acxt, parent_sd); - rc = sysfs_add_one(&acxt, sd); + sysfs_addrm_start(&acxt); + rc = sysfs_add_one(&acxt, sd, parent_sd); sysfs_addrm_finish(&acxt); if (rc == 0) @@ -701,7 +702,7 @@ 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, NULL, name, p_sd); + KOBJ_NS_TYPE_NONE, name, NULL, p_sd); } /** @@ -730,14 +731,14 @@ static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj) } /** - * sysfs_create_dir - create a directory for an object. - * @kobj: object we're creating directory for. + * 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(struct kobject *kobj) +int sysfs_create_dir_ns(struct kobject *kobj, const void *ns) { enum kobj_ns_type type; struct sysfs_dirent *parent_sd, *sd; - const void *ns = NULL; int error = 0; BUG_ON(!kobj); @@ -750,11 +751,9 @@ int sysfs_create_dir(struct kobject *kobj) if (!parent_sd) return -ENOENT; - if (sysfs_ns_type(parent_sd)) - ns = kobj->ktype->namespace(kobj); type = sysfs_read_ns_type(kobj); - error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd); + error = create_dir(kobj, parent_sd, type, kobject_name(kobj), ns, &sd); if (!error) kobj->sd = sd; return error; @@ -776,7 +775,7 @@ static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry, type = sysfs_ns_type(parent_sd); ns = sysfs_info(dir->i_sb)->ns[type]; - sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name); + sd = sysfs_find_dirent(parent_sd, dentry->d_name.name, ns); /* no such entry */ if (!sd) { @@ -807,41 +806,128 @@ const struct inode_operations sysfs_dir_inode_operations = { .setxattr = sysfs_setxattr, }; -static void remove_dir(struct sysfs_dirent *sd) +static struct sysfs_dirent *sysfs_leftmost_descendant(struct sysfs_dirent *pos) { - struct sysfs_addrm_cxt acxt; + struct sysfs_dirent *last; - sysfs_addrm_start(&acxt, sd->s_parent); - sysfs_remove_one(&acxt, sd); - sysfs_addrm_finish(&acxt); + 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; } -void sysfs_remove_subdir(struct sysfs_dirent *sd) +/** + * 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) { - remove_dir(sd); + 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; -static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) + 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; - struct rb_node *pos; - if (!dir_sd) - return; + sysfs_addrm_start(&acxt); + __sysfs_remove(&acxt, sd); + sysfs_addrm_finish(&acxt); +} - pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); - sysfs_addrm_start(&acxt, dir_sd); - pos = rb_first(&dir_sd->s_dir.children); - while (pos) { - struct sysfs_dirent *sd = to_sysfs_dirent(pos); - pos = rb_next(pos); - if (sysfs_type(sd) != SYSFS_DIR) - sysfs_remove_one(&acxt, sd); +/** + * 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); - remove_dir(dir_sd); + if (sd) + return 0; + else + return -ENOENT; } /** @@ -852,21 +938,34 @@ static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) * 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; - spin_lock(&sysfs_assoc_lock); + /* + * 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_assoc_lock); + spin_unlock(&sysfs_symlink_target_lock); - __sysfs_remove_dir(sd); + 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 void *new_ns, - const char *new_name) +int sysfs_rename(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent_sd, + const char *new_name, const void *new_ns) { int error; @@ -878,7 +977,7 @@ int sysfs_rename(struct sysfs_dirent *sd, goto out; /* nothing to rename */ error = -EEXIST; - if (sysfs_find_dirent(new_parent_sd, new_ns, new_name)) + if (sysfs_find_dirent(new_parent_sd, new_name, new_ns)) goto out; /* rename sysfs_dirent */ @@ -899,7 +998,7 @@ int sysfs_rename(struct sysfs_dirent *sd, sysfs_get(new_parent_sd); sysfs_put(sd->s_parent); sd->s_ns = new_ns; - sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name); + sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns); sd->s_parent = new_parent_sd; sysfs_link_sibling(sd); @@ -909,30 +1008,25 @@ int sysfs_rename(struct sysfs_dirent *sd, return error; } -int sysfs_rename_dir(struct kobject *kobj, const char *new_name) +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; - const void *new_ns = NULL; - - if (sysfs_ns_type(parent_sd)) - new_ns = kobj->ktype->namespace(kobj); - return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name); + return sysfs_rename(kobj->sd, parent_sd, new_name, new_ns); } -int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) +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; - const void *new_ns = NULL; BUG_ON(!sd->s_parent); - if (sysfs_ns_type(sd->s_parent)) - new_ns = kobj->ktype->namespace(kobj); new_parent_sd = new_parent_kobj && new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root; - return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name); + return sysfs_rename(sd, new_parent_sd, sd->s_name, new_ns); } /* Relationship between s_mode and the DT_xxx types */ |