/* * fs/sysfs/dir.c - sysfs core and dir operation implementation * * Copyright (c) 2001-3 Patrick Mochel * Copyright (c) 2007 SUSE Linux Products GmbH * Copyright (c) 2007 Tejun Heo <teheo@suse.de> * * This file is released under the GPLv2. * * Please see Documentation/filesystems/sysfs.txt for more information. */ #undef DEBUG #include <linux/fs.h>#include <linux/mount.h>#include <linux/module.h>#include <linux/kobject.h>#include <linux/namei.h>#include <linux/idr.h>#include <linux/completion.h>#include <linux/mutex.h>#include <linux/slab.h>#include <linux/security.h>#include <linux/hash.h>#include "sysfs.h" DEFINE_MUTEX(sysfs_mutex);DEFINE_SPINLOCK(sysfs_assoc_lock); #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 * * 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){ unsigned long hash = init_name_hash(); unsigned int len = strlen(name); while (len--) hash = partial_name_hash(*name++, hash); hash = ( end_name_hash(hash) ^ hash_ptr( (void *)ns, 31 ) ); hash &= 0x7fffffffU; /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ if (hash < 1) hash += 2; if (hash >= INT_MAX) hash = INT_MAX - 1; return hash;} static int sysfs_name_compare(unsigned int hash, const void *ns, const char *name, const struct sysfs_dirent *sd){ if (hash != sd->s_hash) return hash - sd->s_hash; if (ns != sd->s_ns) return ns - sd->s_ns; return strcmp(name, sd->s_name);} 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, right);} /** * sysfs_link_subling - link sysfs_dirent into sibling rbtree * @sd: sysfs_dirent of interest * * Link @sd into its sibling rbtree which starts from * sd->s_parent->s_dir.children. * * Locking: * mutex_lock(sysfs_mutex) * * RETURNS: * 0 on susccess -EEXIST on failure. */static int sysfs_link_sibling(struct sysfs_dirent *sd){ struct rb_node **node = &sd->s_parent->s_dir.children.rb_node; struct rb_node *parent = NULL; if (sysfs_type(sd) == SYSFS_DIR) sd->s_parent->s_dir.subdirs++; while (*node) { struct sysfs_dirent *pos; int result; pos = to_sysfs_dirent(*node); parent = *node; result = sysfs_sd_compare(sd, pos); if (result < 0) node = &pos->s_rb.rb_left; else if (result > 0) node = &pos->s_rb.rb_right; else return -EEXIST; } /* add new node and rebalance the tree */ rb_link_node(&sd->s_rb, parent, node); rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children); return 0;} /** * sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree * @sd: sysfs_dirent of interest * * Unlink @sd from its sibling rbtree which starts from * sd->s_parent->s_dir.children. * * Locking: * mutex_lock(sysfs_mutex) */static void sysfs_unlink_sibling(struct sysfs_dirent *sd){ if (sysfs_type(sd) == SYSFS_DIR) sd->s_parent->s_dir.subdirs--; 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 * * Get an active reference of @sd. This function is noop if @sd * is NULL. * * RETURNS: * Pointer to @sd on success, NULL on failure. */struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd){ if (unlikely(!sd)) return NULL; while (1) { int v, t; v = atomic_read(&sd->s_active); if (unlikely(v < 0)) return NULL; t = atomic_cmpxchg(&sd->s_active, v, v + 1); if (likely(t == v)) break; if (t < 0) return NULL; cpu_relax(); } if (likely(!ignore_lockdep(sd))) rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_); return sd;} /** * sysfs_put_active - put an active reference to sysfs_dirent * @sd: sysfs_dirent to put an active reference to * * Put an active reference to @sd. This function is noop if @sd * is NULL. */void sysfs_put_active(struct sysfs_dirent *sd){ int v; if (unlikely(!sd)) return; if (likely(!ignore_lockdep(sd))) rwsem_release(&sd->dep_map, 1, _RET_IP_); v = atomic_dec_return(&sd->s_active); if (likely(v != SD_DEACTIVATED_BIAS)) return; /* atomic_dec_return() is a mb(), we'll always see the updated * sd->u.completion. */ complete(sd->u.completion);} /** * sysfs_deactivate - deactivate sysfs_dirent * @sd: sysfs_dirent to deactivate * * Deny new active references and drain existing ones. */static void sysfs_deactivate(struct sysfs_dirent *sd){ DECLARE_COMPLETION_ONSTACK(wait); int v; BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED)); if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF)) return; sd->u.completion = (void *)&wait; rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_); /* atomic_add_return() is a mb(), put_active() will always see * the updated sd->u.completion. */ v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); if (v != SD_DEACTIVATED_BIAS) { lock_contended(&sd->dep_map, _RET_IP_); wait_for_completion(&wait); } lock_acquired(&sd->dep_map, _RET_IP_); rwsem_release(&sd->dep_map, 1, _RET_IP_);} static int sysfs_alloc_ino(unsigned int *pino){ int ino, rc; retry: spin_lock(&sysfs_ino_lock); rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); spin_unlock(&sysfs_ino_lock); if (rc == -EAGAIN) { if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) goto retry; rc = -ENOMEM; } *pino = ino; return rc;} static void sysfs_free_ino(unsigned int ino){ spin_lock(&sysfs_ino_lock); ida_remove(&sysfs_ino_ida, ino); spin_unlock(&sysfs_ino_lock);} void release_sysfs_dirent(struct sysfs_dirent * sd){ struct sysfs_dirent *parent_sd; repeat: /* Moving/renaming is always done while holding reference. * sd->s_parent won't change beneath us. */ parent_sd = sd->s_parent; if (sysfs_type(sd) == SYSFS_KOBJ_LINK) sysfs_put(sd->s_symlink.target_sd); if (sysfs_type(sd) & SYSFS_COPY_NAME) kfree(sd->s_name); if (sd->s_iattr && sd->s_iattr->ia_secdata) security_release_secctx(sd->s_iattr->ia_secdata, sd->s_iattr->ia_secdata_len); kfree(sd->s_iattr); sysfs_free_ino(sd->s_ino); kmem_cache_free(sysfs_dir_cachep, sd); sd = parent_sd; if (sd && atomic_dec_and_test(&sd->s_count)) goto repeat;} static int sysfs_dentry_delete(const struct dentry *dentry){ struct sysfs_dirent *sd = dentry->d_fsdata; return !!(sd->s_flags & SYSFS_FLAG_REMOVED);} static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd){ struct sysfs_dirent *sd; int is_dir; if (nd->flags & LOOKUP_RCU) return -ECHILD; sd = dentry->d_fsdata; mutex_lock(&sysfs_mutex); /* The sysfs dirent has been deleted */ if (sd->s_flags & SYSFS_FLAG_REMOVED) goto out_bad; /* The sysfs dirent has been moved? */ if (dentry->d_parent->d_fsdata != sd->s_parent) goto out_bad; /* The sysfs dirent has been renamed */ if (strcmp(dentry->d_name.name, sd->s_name) != 0) goto out_bad; mutex_unlock(&sysfs_mutex);out_valid: return 1;out_bad: /* Remove the dentry from the dcache hashes. * If this is a deleted dentry we use d_drop instead of d_delete * so sysfs doesn't need to cope with negative dentries. * * If this is a dentry that has simply been renamed we * use d_drop to remove it from the dcache lookup on its * old parent. If this dentry persists later when a lookup * is performed at its new name the dentry will be readded * to the dcache hashes. */ is_dir = (sysfs_type(sd) == SYSFS_DIR); mutex_unlock(&sysfs_mutex); if (is_dir) { /* If we have submounts we must allow the vfs caches * to lie about the state of the filesystem to prevent * leaks and other nasty things. */ if (have_submounts(dentry)) goto out_valid; shrink_dcache_parent(dentry); } d_drop(dentry); return 0;} static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode){ struct sysfs_dirent * sd = dentry->d_fsdata; sysfs_put(sd); iput(inode);} static const struct dentry_operations sysfs_dentry_ops = { .d_revalidate = sysfs_dentry_revalidate, .d_delete = sysfs_dentry_delete, .d_iput = sysfs_dentry_iput,}; struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type){ char *dup_name = NULL; struct sysfs_dirent *sd; if (type & SYSFS_COPY_NAME) { name = dup_name = kstrdup(name, GFP_KERNEL); if (!name) return NULL; } sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); if (!sd) goto err_out1; if (sysfs_alloc_ino(&sd->s_ino)) goto err_out2; atomic_set(&sd->s_count, 1); atomic_set(&sd->s_active, 0); sd->s_name = name; sd->s_mode = mode; sd->s_flags = type; return sd; err_out2: kmem_cache_free(sysfs_dir_cachep, sd); err_out1: kfree(dup_name); return NULL;} /** * 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. * * 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){ memset(acxt, 0, sizeof(*acxt)); acxt->parent_sd = parent_sd; mutex_lock(&sysfs_mutex);} /** * __sysfs_add_one - add sysfs_dirent to parent without warning * @acxt: addrm context to use * @sd: sysfs_dirent to be added * * 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. * * 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_inode_attrs *ps_iattr; int ret; if (!!sysfs_ns_type(acxt->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); return -EINVAL; } sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name); sd->s_parent = sysfs_get(acxt->parent_sd); ret = sysfs_link_sibling(sd); if (ret) return ret; /* Update timestamps on the parent */ ps_iattr = acxt->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; } return 0;} /** * sysfs_pathname - return full path to sysfs dirent * @sd: sysfs_dirent whose path we want * @path: caller allocated buffer * * Gives the name "/" to the sysfs_root entry; any path returned * is relative to wherever sysfs is mounted. * * XXX: does no error checking on @path size */static char *sysfs_pathname(struct sysfs_dirent *sd, char *path){ if (sd->s_parent) { sysfs_pathname(sd->s_parent, path); strcat(path, "/"); } strcat(path, sd->s_name); return path;} /** * sysfs_add_one - add sysfs_dirent to parent * @acxt: addrm context to useLines 1–500 of 1068. 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/* * fs/sysfs/dir.c - sysfs core and dir operation implementation * * Copyright (c) 2001-3 Patrick Mochel * Copyright (c) 2007 SUSE Linux Products GmbH * Copyright (c) 2007 Tejun Heo <teheo@suse.de> * * This file is released under the GPLv2. * * Please see Documentation/filesystems/sysfs.txt for more information. */ #undef DEBUG #include <linux/fs.h> #include <linux/mount.h> #include <linux/module.h> #include <linux/kobject.h> #include <linux/namei.h> #include <linux/idr.h> #include <linux/completion.h> #include <linux/mutex.h> #include <linux/slab.h> #include <linux/security.h> #include <linux/hash.h> #include "sysfs.h" DEFINE_MUTEX(sysfs_mutex); DEFINE_SPINLOCK(sysfs_assoc_lock); #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 * * 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) { unsigned long hash = init_name_hash(); unsigned int len = strlen(name); while (len--) hash = partial_name_hash(*name++, hash); hash = ( end_name_hash(hash) ^ hash_ptr( (void *)ns, 31 ) ); hash &= 0x7fffffffU; /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ if (hash < 1) hash += 2; if (hash >= INT_MAX) hash = INT_MAX - 1; return hash; } static int sysfs_name_compare(unsigned int hash, const void *ns, const char *name, const struct sysfs_dirent *sd) { if (hash != sd->s_hash) return hash - sd->s_hash; if (ns != sd->s_ns) return ns - sd->s_ns; return strcmp(name, sd->s_name); } 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, right); } /** * sysfs_link_subling - link sysfs_dirent into sibling rbtree * @sd: sysfs_dirent of interest * * Link @sd into its sibling rbtree which starts from * sd->s_parent->s_dir.children. * * Locking: * mutex_lock(sysfs_mutex) * * RETURNS: * 0 on susccess -EEXIST on failure. */ static int sysfs_link_sibling(struct sysfs_dirent *sd) { struct rb_node **node = &sd->s_parent->s_dir.children.rb_node; struct rb_node *parent = NULL; if (sysfs_type(sd) == SYSFS_DIR) sd->s_parent->s_dir.subdirs++; while (*node) { struct sysfs_dirent *pos; int result; pos = to_sysfs_dirent(*node); parent = *node; result = sysfs_sd_compare(sd, pos); if (result < 0) node = &pos->s_rb.rb_left; else if (result > 0) node = &pos->s_rb.rb_right; else return -EEXIST; } /* add new node and rebalance the tree */ rb_link_node(&sd->s_rb, parent, node); rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children); return 0; } /** * sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree * @sd: sysfs_dirent of interest * * Unlink @sd from its sibling rbtree which starts from * sd->s_parent->s_dir.children. * * Locking: * mutex_lock(sysfs_mutex) */ static void sysfs_unlink_sibling(struct sysfs_dirent *sd) { if (sysfs_type(sd) == SYSFS_DIR) sd->s_parent->s_dir.subdirs--; 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 * * Get an active reference of @sd. This function is noop if @sd * is NULL. * * RETURNS: * Pointer to @sd on success, NULL on failure. */ struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) { if (unlikely(!sd)) return NULL; while (1) { int v, t; v = atomic_read(&sd->s_active); if (unlikely(v < 0)) return NULL; t = atomic_cmpxchg(&sd->s_active, v, v + 1); if (likely(t == v)) break; if (t < 0) return NULL; cpu_relax(); } if (likely(!ignore_lockdep(sd))) rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_); return sd; } /** * sysfs_put_active - put an active reference to sysfs_dirent * @sd: sysfs_dirent to put an active reference to * * Put an active reference to @sd. This function is noop if @sd * is NULL. */ void sysfs_put_active(struct sysfs_dirent *sd) { int v; if (unlikely(!sd)) return; if (likely(!ignore_lockdep(sd))) rwsem_release(&sd->dep_map, 1, _RET_IP_); v = atomic_dec_return(&sd->s_active); if (likely(v != SD_DEACTIVATED_BIAS)) return; /* atomic_dec_return() is a mb(), we'll always see the updated * sd->u.completion. */ complete(sd->u.completion); } /** * sysfs_deactivate - deactivate sysfs_dirent * @sd: sysfs_dirent to deactivate * * Deny new active references and drain existing ones. */ static void sysfs_deactivate(struct sysfs_dirent *sd) { DECLARE_COMPLETION_ONSTACK(wait); int v; BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED)); if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF)) return; sd->u.completion = (void *)&wait; rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_); /* atomic_add_return() is a mb(), put_active() will always see * the updated sd->u.completion. */ v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); if (v != SD_DEACTIVATED_BIAS) { lock_contended(&sd->dep_map, _RET_IP_); wait_for_completion(&wait); } lock_acquired(&sd->dep_map, _RET_IP_); rwsem_release(&sd->dep_map, 1, _RET_IP_); } static int sysfs_alloc_ino(unsigned int *pino) { int ino, rc; retry: spin_lock(&sysfs_ino_lock); rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); spin_unlock(&sysfs_ino_lock); if (rc == -EAGAIN) { if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) goto retry; rc = -ENOMEM; } *pino = ino; return rc; } static void sysfs_free_ino(unsigned int ino) { spin_lock(&sysfs_ino_lock); ida_remove(&sysfs_ino_ida, ino); spin_unlock(&sysfs_ino_lock); } void release_sysfs_dirent(struct sysfs_dirent * sd) { struct sysfs_dirent *parent_sd; repeat: /* Moving/renaming is always done while holding reference. * sd->s_parent won't change beneath us. */ parent_sd = sd->s_parent; if (sysfs_type(sd) == SYSFS_KOBJ_LINK) sysfs_put(sd->s_symlink.target_sd); if (sysfs_type(sd) & SYSFS_COPY_NAME) kfree(sd->s_name); if (sd->s_iattr && sd->s_iattr->ia_secdata) security_release_secctx(sd->s_iattr->ia_secdata, sd->s_iattr->ia_secdata_len); kfree(sd->s_iattr); sysfs_free_ino(sd->s_ino); kmem_cache_free(sysfs_dir_cachep, sd); sd = parent_sd; if (sd && atomic_dec_and_test(&sd->s_count)) goto repeat; } static int sysfs_dentry_delete(const struct dentry *dentry) { struct sysfs_dirent *sd = dentry->d_fsdata; return !!(sd->s_flags & SYSFS_FLAG_REMOVED); } static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd) { struct sysfs_dirent *sd; int is_dir; if (nd->flags & LOOKUP_RCU) return -ECHILD; sd = dentry->d_fsdata; mutex_lock(&sysfs_mutex); /* The sysfs dirent has been deleted */ if (sd->s_flags & SYSFS_FLAG_REMOVED) goto out_bad; /* The sysfs dirent has been moved? */ if (dentry->d_parent->d_fsdata != sd->s_parent) goto out_bad; /* The sysfs dirent has been renamed */ if (strcmp(dentry->d_name.name, sd->s_name) != 0) goto out_bad; mutex_unlock(&sysfs_mutex); out_valid: return 1; out_bad: /* Remove the dentry from the dcache hashes. * If this is a deleted dentry we use d_drop instead of d_delete * so sysfs doesn't need to cope with negative dentries. * * If this is a dentry that has simply been renamed we * use d_drop to remove it from the dcache lookup on its * old parent. If this dentry persists later when a lookup * is performed at its new name the dentry will be readded * to the dcache hashes. */ is_dir = (sysfs_type(sd) == SYSFS_DIR); mutex_unlock(&sysfs_mutex); if (is_dir) { /* If we have submounts we must allow the vfs caches * to lie about the state of the filesystem to prevent * leaks and other nasty things. */ if (have_submounts(dentry)) goto out_valid; shrink_dcache_parent(dentry); } d_drop(dentry); return 0; } static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode) { struct sysfs_dirent * sd = dentry->d_fsdata; sysfs_put(sd); iput(inode); } static const struct dentry_operations sysfs_dentry_ops = { .d_revalidate = sysfs_dentry_revalidate, .d_delete = sysfs_dentry_delete, .d_iput = sysfs_dentry_iput, }; struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) { char *dup_name = NULL; struct sysfs_dirent *sd; if (type & SYSFS_COPY_NAME) { name = dup_name = kstrdup(name, GFP_KERNEL); if (!name) return NULL; } sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); if (!sd) goto err_out1; if (sysfs_alloc_ino(&sd->s_ino)) goto err_out2; atomic_set(&sd->s_count, 1); atomic_set(&sd->s_active, 0); sd->s_name = name; sd->s_mode = mode; sd->s_flags = type; return sd; err_out2: kmem_cache_free(sysfs_dir_cachep, sd); err_out1: kfree(dup_name); return NULL; } /** * 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. * * 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) { memset(acxt, 0, sizeof(*acxt)); acxt->parent_sd = parent_sd; mutex_lock(&sysfs_mutex); } /** * __sysfs_add_one - add sysfs_dirent to parent without warning * @acxt: addrm context to use * @sd: sysfs_dirent to be added * * 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. * * 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_inode_attrs *ps_iattr; int ret; if (!!sysfs_ns_type(acxt->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); return -EINVAL; } sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name); sd->s_parent = sysfs_get(acxt->parent_sd); ret = sysfs_link_sibling(sd); if (ret) return ret; /* Update timestamps on the parent */ ps_iattr = acxt->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; } return 0; } /** * sysfs_pathname - return full path to sysfs dirent * @sd: sysfs_dirent whose path we want * @path: caller allocated buffer * * Gives the name "/" to the sysfs_root entry; any path returned * is relative to wherever sysfs is mounted. * * XXX: does no error checking on @path size */ static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) { if (sd->s_parent) { sysfs_pathname(sd->s_parent, path); strcat(path, "/"); } strcat(path, sd->s_name); return path; } /** * sysfs_add_one - add sysfs_dirent to parent * @acxt: addrm context to use