| /* |
| * dir.c - Operations for sysfs directories. |
| */ |
| |
| #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 <asm/semaphore.h> |
| #include "sysfs.h" |
| |
| DEFINE_MUTEX(sysfs_mutex); |
| spinlock_t sysfs_assoc_lock = SPIN_LOCK_UNLOCKED; |
| |
| static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED; |
| static DEFINE_IDA(sysfs_ino_ida); |
| |
| /** |
| * sysfs_link_sibling - link sysfs_dirent into sibling list |
| * @sd: sysfs_dirent of interest |
| * |
| * Link @sd into its sibling list which starts from |
| * sd->s_parent->s_children. |
| * |
| * Locking: |
| * mutex_lock(sysfs_mutex) |
| */ |
| void sysfs_link_sibling(struct sysfs_dirent *sd) |
| { |
| struct sysfs_dirent *parent_sd = sd->s_parent; |
| |
| BUG_ON(sd->s_sibling); |
| sd->s_sibling = parent_sd->s_children; |
| parent_sd->s_children = sd; |
| } |
| |
| /** |
| * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list |
| * @sd: sysfs_dirent of interest |
| * |
| * Unlink @sd from its sibling list which starts from |
| * sd->s_parent->s_children. |
| * |
| * Locking: |
| * mutex_lock(sysfs_mutex) |
| */ |
| void sysfs_unlink_sibling(struct sysfs_dirent *sd) |
| { |
| struct sysfs_dirent **pos; |
| |
| for (pos = &sd->s_parent->s_children; *pos; pos = &(*pos)->s_sibling) { |
| if (*pos == sd) { |
| *pos = sd->s_sibling; |
| sd->s_sibling = NULL; |
| break; |
| } |
| } |
| } |
| |
| /** |
| * sysfs_get_dentry - get dentry for the given sysfs_dirent |
| * @sd: sysfs_dirent of interest |
| * |
| * Get dentry for @sd. Dentry is looked up if currently not |
| * present. This function climbs sysfs_dirent tree till it |
| * reaches a sysfs_dirent with valid dentry attached and descends |
| * down from there looking up dentry for each step. |
| * |
| * LOCKING: |
| * Kernel thread context (may sleep) |
| * |
| * RETURNS: |
| * Pointer to found dentry on success, ERR_PTR() value on error. |
| */ |
| struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd) |
| { |
| struct sysfs_dirent *cur; |
| struct dentry *parent_dentry, *dentry; |
| int i, depth; |
| |
| /* Find the first parent which has valid s_dentry and get the |
| * dentry. |
| */ |
| mutex_lock(&sysfs_mutex); |
| restart0: |
| spin_lock(&sysfs_assoc_lock); |
| restart1: |
| spin_lock(&dcache_lock); |
| |
| dentry = NULL; |
| depth = 0; |
| cur = sd; |
| while (!cur->s_dentry || !cur->s_dentry->d_inode) { |
| if (cur->s_flags & SYSFS_FLAG_REMOVED) { |
| dentry = ERR_PTR(-ENOENT); |
| depth = 0; |
| break; |
| } |
| cur = cur->s_parent; |
| depth++; |
| } |
| if (!IS_ERR(dentry)) |
| dentry = dget_locked(cur->s_dentry); |
| |
| spin_unlock(&dcache_lock); |
| spin_unlock(&sysfs_assoc_lock); |
| |
| /* from the found dentry, look up depth times */ |
| while (depth--) { |
| /* find and get depth'th ancestor */ |
| for (cur = sd, i = 0; cur && i < depth; i++) |
| cur = cur->s_parent; |
| |
| /* This can happen if tree structure was modified due |
| * to move/rename. Restart. |
| */ |
| if (i != depth) { |
| dput(dentry); |
| goto restart0; |
| } |
| |
| sysfs_get(cur); |
| |
| mutex_unlock(&sysfs_mutex); |
| |
| /* look it up */ |
| parent_dentry = dentry; |
| dentry = lookup_one_len_kern(cur->s_name, parent_dentry, |
| strlen(cur->s_name)); |
| dput(parent_dentry); |
| |
| if (IS_ERR(dentry)) { |
| sysfs_put(cur); |
| return dentry; |
| } |
| |
| mutex_lock(&sysfs_mutex); |
| spin_lock(&sysfs_assoc_lock); |
| |
| /* This, again, can happen if tree structure has |
| * changed and we looked up the wrong thing. Restart. |
| */ |
| if (cur->s_dentry != dentry) { |
| dput(dentry); |
| sysfs_put(cur); |
| goto restart1; |
| } |
| |
| spin_unlock(&sysfs_assoc_lock); |
| |
| sysfs_put(cur); |
| } |
| |
| mutex_unlock(&sysfs_mutex); |
| return dentry; |
| } |
| |
| /** |
| * 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)) |
| return sd; |
| if (t < 0) |
| return NULL; |
| |
| cpu_relax(); |
| } |
| } |
| |
| /** |
| * 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) |
| { |
| struct completion *cmpl; |
| int v; |
| |
| if (unlikely(!sd)) |
| return; |
| |
| 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->s_sibling. |
| */ |
| cmpl = (void *)sd->s_sibling; |
| complete(cmpl); |
| } |
| |
| /** |
| * sysfs_get_active_two - get active references to sysfs_dirent and parent |
| * @sd: sysfs_dirent of interest |
| * |
| * Get active reference to @sd and its parent. Parent's active |
| * reference is grabbed first. This function is noop if @sd is |
| * NULL. |
| * |
| * RETURNS: |
| * Pointer to @sd on success, NULL on failure. |
| */ |
| struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd) |
| { |
| if (sd) { |
| if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent))) |
| return NULL; |
| if (unlikely(!sysfs_get_active(sd))) { |
| sysfs_put_active(sd->s_parent); |
| return NULL; |
| } |
| } |
| return sd; |
| } |
| |
| /** |
| * sysfs_put_active_two - put active references to sysfs_dirent and parent |
| * @sd: sysfs_dirent of interest |
| * |
| * Put active references to @sd and its parent. This function is |
| * noop if @sd is NULL. |
| */ |
| void sysfs_put_active_two(struct sysfs_dirent *sd) |
| { |
| if (sd) { |
| sysfs_put_active(sd); |
| sysfs_put_active(sd->s_parent); |
| } |
| } |
| |
| /** |
| * 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_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED)); |
| sd->s_sibling = (void *)&wait; |
| |
| /* atomic_add_return() is a mb(), put_active() will always see |
| * the updated sd->s_sibling. |
| */ |
| v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); |
| |
| if (v != SD_DEACTIVATED_BIAS) |
| wait_for_completion(&wait); |
| |
| sd->s_sibling = NULL; |
| } |
| |
| static int sysfs_alloc_ino(ino_t *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(ino_t 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_elem.symlink.target_sd); |
| if (sysfs_type(sd) & SYSFS_COPY_NAME) |
| kfree(sd->s_name); |
| 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 void sysfs_d_iput(struct dentry * dentry, struct inode * inode) |
| { |
| struct sysfs_dirent * sd = dentry->d_fsdata; |
| |
| if (sd) { |
| /* sd->s_dentry is protected with sysfs_assoc_lock. |
| * This allows sysfs_drop_dentry() to dereference it. |
| */ |
| spin_lock(&sysfs_assoc_lock); |
| |
| /* The dentry might have been deleted or another |
| * lookup could have happened updating sd->s_dentry to |
| * point the new dentry. Ignore if it isn't pointing |
| * to this dentry. |
| */ |
| if (sd->s_dentry == dentry) |
| sd->s_dentry = NULL; |
| spin_unlock(&sysfs_assoc_lock); |
| sysfs_put(sd); |
| } |
| iput(inode); |
| } |
| |
| static struct dentry_operations sysfs_dentry_ops = { |
| .d_iput = sysfs_d_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); |
| atomic_set(&sd->s_event, 1); |
| |
| 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_attach_dentry - associate sysfs_dirent with dentry |
| * @sd: target sysfs_dirent |
| * @dentry: dentry to associate |
| * |
| * Associate @sd with @dentry. This is protected by |
| * sysfs_assoc_lock to avoid race with sysfs_d_iput(). |
| * |
| * LOCKING: |
| * mutex_lock(sysfs_mutex) |
| */ |
| static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry) |
| { |
| dentry->d_op = &sysfs_dentry_ops; |
| dentry->d_fsdata = sysfs_get(sd); |
| |
| /* protect sd->s_dentry against sysfs_d_iput */ |
| spin_lock(&sysfs_assoc_lock); |
| sd->s_dentry = dentry; |
| spin_unlock(&sysfs_assoc_lock); |
| |
| d_rehash(dentry); |
| } |
| |
| static int sysfs_ilookup_test(struct inode *inode, void *arg) |
| { |
| struct sysfs_dirent *sd = arg; |
| return inode->i_ino == sd->s_ino; |
| } |
| |
| /** |
| * 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, grabs inode for @parent_sd if available and lock |
| * i_mutex of it. @acxt is used to keep and pass context to |
| * other addrm functions. |
| * |
| * LOCKING: |
| * Kernel thread context (may sleep). sysfs_mutex is locked on |
| * return. i_mutex of parent inode is locked on return if |
| * available. |
| */ |
| void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, |
| struct sysfs_dirent *parent_sd) |
| { |
| struct inode *inode; |
| |
| memset(acxt, 0, sizeof(*acxt)); |
| acxt->parent_sd = parent_sd; |
| |
| /* Lookup parent inode. inode initialization and I_NEW |
| * clearing are protected by sysfs_mutex. By grabbing it and |
| * looking up with _nowait variant, inode state can be |
| * determined reliably. |
| */ |
| mutex_lock(&sysfs_mutex); |
| |
| inode = ilookup5_nowait(sysfs_sb, parent_sd->s_ino, sysfs_ilookup_test, |
| parent_sd); |
| |
| if (inode && !(inode->i_state & I_NEW)) { |
| /* parent inode available */ |
| acxt->parent_inode = inode; |
| |
| /* sysfs_mutex is below i_mutex in lock hierarchy. |
| * First, trylock i_mutex. If fails, unlock |
| * sysfs_mutex and lock them in order. |
| */ |
| if (!mutex_trylock(&inode->i_mutex)) { |
| mutex_unlock(&sysfs_mutex); |
| mutex_lock(&inode->i_mutex); |
| mutex_lock(&sysfs_mutex); |
| } |
| } else |
| iput(inode); |
| } |
| |
| /** |
| * sysfs_add_one - add sysfs_dirent to parent |
| * @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. @sd is NOT |
| * linked into the children list of the parent. The caller |
| * should invoke sysfs_link_sibling() after this function |
| * completes if @sd needs to be on 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(). |
| */ |
| void sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) |
| { |
| sd->s_parent = sysfs_get(acxt->parent_sd); |
| |
| if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) |
| inc_nlink(acxt->parent_inode); |
| |
| acxt->cnt++; |
| } |
| |
| /** |
| * sysfs_remove_one - remove sysfs_dirent from parent |
| * @acxt: addrm context to use |
| * @sd: sysfs_dirent to be added |
| * |
| * Mark @sd removed and drop nlink of parent inode if @sd is a |
| * directory. @sd is NOT unlinked from the children list of the |
| * parent. The caller is repsonsible for removing @sd from the |
| * children list before calling this function. |
| * |
| * 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(). |
| */ |
| void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) |
| { |
| BUG_ON(sd->s_sibling || (sd->s_flags & SYSFS_FLAG_REMOVED)); |
| |
| sd->s_flags |= SYSFS_FLAG_REMOVED; |
| sd->s_sibling = acxt->removed; |
| acxt->removed = sd; |
| |
| if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode) |
| drop_nlink(acxt->parent_inode); |
| |
| acxt->cnt++; |
| } |
| |
| /** |
| * sysfs_drop_dentry - drop dentry for the specified sysfs_dirent |
| * @sd: target sysfs_dirent |
| * |
| * Drop dentry for @sd. @sd must have been unlinked from its |
| * parent on entry to this function such that it can't be looked |
| * up anymore. |
| * |
| * @sd->s_dentry which is protected with sysfs_assoc_lock points |
| * to the currently associated dentry but we're not holding a |
| * reference to it and racing with dput(). Grab dcache_lock and |
| * verify dentry before dropping it. If @sd->s_dentry is NULL or |
| * dput() beats us, no need to bother. |
| */ |
| static void sysfs_drop_dentry(struct sysfs_dirent *sd) |
| { |
| struct dentry *dentry = NULL; |
| struct inode *inode; |
| |
| /* We're not holding a reference to ->s_dentry dentry but the |
| * field will stay valid as long as sysfs_assoc_lock is held. |
| */ |
| spin_lock(&sysfs_assoc_lock); |
| spin_lock(&dcache_lock); |
| |
| /* drop dentry if it's there and dput() didn't kill it yet */ |
| if (sd->s_dentry && sd->s_dentry->d_inode) { |
| dentry = dget_locked(sd->s_dentry); |
| spin_lock(&dentry->d_lock); |
| __d_drop(dentry); |
| spin_unlock(&dentry->d_lock); |
| } |
| |
| spin_unlock(&dcache_lock); |
| spin_unlock(&sysfs_assoc_lock); |
| |
| /* dentries for shadowed inodes are pinned, unpin */ |
| if (dentry && sysfs_is_shadowed_inode(dentry->d_inode)) |
| dput(dentry); |
| dput(dentry); |
| |
| /* adjust nlink and update timestamp */ |
| inode = ilookup(sysfs_sb, sd->s_ino); |
| if (inode) { |
| mutex_lock(&inode->i_mutex); |
| |
| inode->i_ctime = CURRENT_TIME; |
| drop_nlink(inode); |
| if (sysfs_type(sd) == SYSFS_DIR) |
| drop_nlink(inode); |
| |
| mutex_unlock(&inode->i_mutex); |
| iput(inode); |
| } |
| } |
| |
| /** |
| * 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. Timestamps on the parent inode are updated. |
| * |
| * LOCKING: |
| * All mutexes acquired by sysfs_addrm_start() are released. |
| * |
| * RETURNS: |
| * Number of added/removed sysfs_dirents since sysfs_addrm_start(). |
| */ |
| int sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) |
| { |
| /* release resources acquired by sysfs_addrm_start() */ |
| mutex_unlock(&sysfs_mutex); |
| if (acxt->parent_inode) { |
| struct inode *inode = acxt->parent_inode; |
| |
| /* if added/removed, update timestamps on the parent */ |
| if (acxt->cnt) |
| inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
| |
| mutex_unlock(&inode->i_mutex); |
| iput(inode); |
| } |
| |
| /* kill removed sysfs_dirents */ |
| while (acxt->removed) { |
| struct sysfs_dirent *sd = acxt->removed; |
| |
| acxt->removed = sd->s_sibling; |
| sd->s_sibling = NULL; |
| |
| sysfs_drop_dentry(sd); |
| sysfs_deactivate(sd); |
| sysfs_put(sd); |
| } |
| |
| return acxt->cnt; |
| } |
| |
| /** |
| * sysfs_find_dirent - find sysfs_dirent with the given name |
| * @parent_sd: sysfs_dirent to search under |
| * @name: name to look for |
| * |
| * 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) |
| { |
| struct sysfs_dirent *sd; |
| |
| for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) |
| if (sysfs_type(sd) && !strcmp(sd->s_name, name)) |
| return sd; |
| return NULL; |
| } |
| |
| /** |
| * sysfs_get_dirent - find and get sysfs_dirent with the given name |
| * @parent_sd: sysfs_dirent to search under |
| * @name: name to look for |
| * |
| * 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(struct sysfs_dirent *parent_sd, |
| const unsigned char *name) |
| { |
| struct sysfs_dirent *sd; |
| |
| mutex_lock(&sysfs_mutex); |
| sd = sysfs_find_dirent(parent_sd, name); |
| sysfs_get(sd); |
| mutex_unlock(&sysfs_mutex); |
| |
| return sd; |
| } |
| |
| static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, |
| const char *name, 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; |
| |
| /* allocate */ |
| sd = sysfs_new_dirent(name, mode, SYSFS_DIR); |
| if (!sd) |
| return -ENOMEM; |
| sd->s_elem.dir.kobj = kobj; |
| |
| /* link in */ |
| sysfs_addrm_start(&acxt, parent_sd); |
| |
| if (!sysfs_find_dirent(parent_sd, name)) { |
| sysfs_add_one(&acxt, sd); |
| sysfs_link_sibling(sd); |
| } |
| |
| if (!sysfs_addrm_finish(&acxt)) { |
| sysfs_put(sd); |
| return -EEXIST; |
| } |
| |
| *p_sd = sd; |
| return 0; |
| } |
| |
| int sysfs_create_subdir(struct kobject *kobj, const char *name, |
| struct sysfs_dirent **p_sd) |
| { |
| return create_dir(kobj, kobj->sd, name, p_sd); |
| } |
| |
| /** |
| * sysfs_create_dir - create a directory for an object. |
| * @kobj: object we're creating directory for. |
| * @shadow_parent: parent object. |
| */ |
| int sysfs_create_dir(struct kobject *kobj, |
| struct sysfs_dirent *shadow_parent_sd) |
| { |
| struct sysfs_dirent *parent_sd, *sd; |
| int error = 0; |
| |
| BUG_ON(!kobj); |
| |
| if (shadow_parent_sd) |
| parent_sd = shadow_parent_sd; |
| else if (kobj->parent) |
| parent_sd = kobj->parent->sd; |
| else if (sysfs_mount && sysfs_mount->mnt_sb) |
| parent_sd = sysfs_mount->mnt_sb->s_root->d_fsdata; |
| else |
| return -EFAULT; |
| |
| error = create_dir(kobj, parent_sd, kobject_name(kobj), &sd); |
| if (!error) |
| kobj->sd = sd; |
| return error; |
| } |
| |
| static int sysfs_count_nlink(struct sysfs_dirent *sd) |
| { |
| struct sysfs_dirent *child; |
| int nr = 0; |
| |
| for (child = sd->s_children; child; child = child->s_sibling) |
| if (sysfs_type(child) == SYSFS_DIR) |
| nr++; |
| return nr + 2; |
| } |
| |
| static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, |
| struct nameidata *nd) |
| { |
| struct dentry *ret = NULL; |
| struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata; |
| struct sysfs_dirent * sd; |
| struct bin_attribute *bin_attr; |
| struct inode *inode; |
| int found = 0; |
| |
| mutex_lock(&sysfs_mutex); |
| |
| for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) { |
| if (sysfs_type(sd) && |
| !strcmp(sd->s_name, dentry->d_name.name)) { |
| found = 1; |
| break; |
| } |
| } |
| |
| /* no such entry */ |
| if (!found) |
| goto out_unlock; |
| |
| /* attach dentry and inode */ |
| inode = sysfs_get_inode(sd); |
| if (!inode) { |
| ret = ERR_PTR(-ENOMEM); |
| goto out_unlock; |
| } |
| |
| if (inode->i_state & I_NEW) { |
| /* initialize inode according to type */ |
| switch (sysfs_type(sd)) { |
| case SYSFS_DIR: |
| inode->i_op = &sysfs_dir_inode_operations; |
| inode->i_fop = &sysfs_dir_operations; |
| inode->i_nlink = sysfs_count_nlink(sd); |
| break; |
| case SYSFS_KOBJ_ATTR: |
| inode->i_size = PAGE_SIZE; |
| inode->i_fop = &sysfs_file_operations; |
| break; |
| case SYSFS_KOBJ_BIN_ATTR: |
| bin_attr = sd->s_elem.bin_attr.bin_attr; |
| inode->i_size = bin_attr->size; |
| inode->i_fop = &bin_fops; |
| break; |
| case SYSFS_KOBJ_LINK: |
| inode->i_op = &sysfs_symlink_inode_operations; |
| break; |
| default: |
| BUG(); |
| } |
| } |
| |
| sysfs_instantiate(dentry, inode); |
| sysfs_attach_dentry(sd, dentry); |
| |
| out_unlock: |
| mutex_unlock(&sysfs_mutex); |
| return ret; |
| } |
| |
| const struct inode_operations sysfs_dir_inode_operations = { |
| .lookup = sysfs_lookup, |
| .setattr = sysfs_setattr, |
| }; |
| |
| static void remove_dir(struct sysfs_dirent *sd) |
| { |
| struct sysfs_addrm_cxt acxt; |
| |
| sysfs_addrm_start(&acxt, sd->s_parent); |
| sysfs_unlink_sibling(sd); |
| sysfs_remove_one(&acxt, sd); |
| sysfs_addrm_finish(&acxt); |
| } |
| |
| void sysfs_remove_subdir(struct sysfs_dirent *sd) |
| { |
| remove_dir(sd); |
| } |
| |
| |
| static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) |
| { |
| struct sysfs_addrm_cxt acxt; |
| struct sysfs_dirent **pos; |
| |
| if (!dir_sd) |
| return; |
| |
| pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); |
| sysfs_addrm_start(&acxt, dir_sd); |
| pos = &dir_sd->s_children; |
| while (*pos) { |
| struct sysfs_dirent *sd = *pos; |
| |
| if (sysfs_type(sd) && sysfs_type(sd) != SYSFS_DIR) { |
| *pos = sd->s_sibling; |
| sd->s_sibling = NULL; |
| sysfs_remove_one(&acxt, sd); |
| } else |
| pos = &(*pos)->s_sibling; |
| } |
| sysfs_addrm_finish(&acxt); |
| |
| remove_dir(dir_sd); |
| } |
| |
| /** |
| * 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; |
| |
| spin_lock(&sysfs_assoc_lock); |
| kobj->sd = NULL; |
| spin_unlock(&sysfs_assoc_lock); |
| |
| __sysfs_remove_dir(sd); |
| } |
| |
| int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd, |
| const char *new_name) |
| { |
| struct sysfs_dirent *sd = kobj->sd; |
| struct dentry *new_parent = NULL; |
| struct dentry *old_dentry = NULL, *new_dentry = NULL; |
| const char *dup_name = NULL; |
| int error; |
| |
| /* get dentries */ |
| old_dentry = sysfs_get_dentry(sd); |
| if (IS_ERR(old_dentry)) { |
| error = PTR_ERR(old_dentry); |
| goto out_dput; |
| } |
| |
| new_parent = sysfs_get_dentry(new_parent_sd); |
| if (IS_ERR(new_parent)) { |
| error = PTR_ERR(new_parent); |
| goto out_dput; |
| } |
| |
| /* lock new_parent and get dentry for new name */ |
| mutex_lock(&new_parent->d_inode->i_mutex); |
| |
| new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name)); |
| if (IS_ERR(new_dentry)) { |
| error = PTR_ERR(new_dentry); |
| goto out_unlock; |
| } |
| |
| /* By allowing two different directories with the same |
| * d_parent we allow this routine to move between different |
| * shadows of the same directory |
| */ |
| error = -EINVAL; |
| if (old_dentry->d_parent->d_inode != new_parent->d_inode || |
| new_dentry->d_parent->d_inode != new_parent->d_inode || |
| old_dentry == new_dentry) |
| goto out_unlock; |
| |
| error = -EEXIST; |
| if (new_dentry->d_inode) |
| goto out_unlock; |
| |
| /* rename kobject and sysfs_dirent */ |
| error = -ENOMEM; |
| new_name = dup_name = kstrdup(new_name, GFP_KERNEL); |
| if (!new_name) |
| goto out_drop; |
| |
| error = kobject_set_name(kobj, "%s", new_name); |
| if (error) |
| goto out_drop; |
| |
| mutex_lock(&sysfs_mutex); |
| |
| dup_name = sd->s_name; |
| sd->s_name = new_name; |
| |
| /* move under the new parent */ |
| d_add(new_dentry, NULL); |
| d_move(sd->s_dentry, new_dentry); |
| |
| sysfs_unlink_sibling(sd); |
| sysfs_get(new_parent_sd); |
| sysfs_put(sd->s_parent); |
| sd->s_parent = new_parent_sd; |
| sysfs_link_sibling(sd); |
| |
| mutex_unlock(&sysfs_mutex); |
| |
| error = 0; |
| goto out_unlock; |
| |
| out_drop: |
| d_drop(new_dentry); |
| out_unlock: |
| mutex_unlock(&new_parent->d_inode->i_mutex); |
| out_dput: |
| kfree(dup_name); |
| dput(new_parent); |
| dput(old_dentry); |
| dput(new_dentry); |
| return error; |
| } |
| |
| int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) |
| { |
| struct sysfs_dirent *sd = kobj->sd; |
| struct sysfs_dirent *new_parent_sd; |
| struct dentry *old_parent, *new_parent = NULL; |
| struct dentry *old_dentry = NULL, *new_dentry = NULL; |
| int error; |
| |
| BUG_ON(!sd->s_parent); |
| new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root; |
| |
| /* get dentries */ |
| old_dentry = sysfs_get_dentry(sd); |
| if (IS_ERR(old_dentry)) { |
| error = PTR_ERR(old_dentry); |
| goto out_dput; |
| } |
| old_parent = sd->s_parent->s_dentry; |
| |
| new_parent = sysfs_get_dentry(new_parent_sd); |
| if (IS_ERR(new_parent)) { |
| error = PTR_ERR(new_parent); |
| goto out_dput; |
| } |
| |
| if (old_parent->d_inode == new_parent->d_inode) { |
| error = 0; |
| goto out_dput; /* nothing to move */ |
| } |
| again: |
| mutex_lock(&old_parent->d_inode->i_mutex); |
| if (!mutex_trylock(&new_parent->d_inode->i_mutex)) { |
| mutex_unlock(&old_parent->d_inode->i_mutex); |
| goto again; |
| } |
| |
| new_dentry = lookup_one_len(kobject_name(kobj), new_parent, strlen(kobject_name(kobj))); |
| if (IS_ERR(new_dentry)) { |
| error = PTR_ERR(new_dentry); |
| goto out_unlock; |
| } else |
| error = 0; |
| d_add(new_dentry, NULL); |
| d_move(sd->s_dentry, new_dentry); |
| dput(new_dentry); |
| |
| /* Remove from old parent's list and insert into new parent's list. */ |
| mutex_lock(&sysfs_mutex); |
| |
| sysfs_unlink_sibling(sd); |
| sysfs_get(new_parent_sd); |
| sysfs_put(sd->s_parent); |
| sd->s_parent = new_parent_sd; |
| sysfs_link_sibling(sd); |
| |
| mutex_unlock(&sysfs_mutex); |
| |
| out_unlock: |
| mutex_unlock(&new_parent->d_inode->i_mutex); |
| mutex_unlock(&old_parent->d_inode->i_mutex); |
| out_dput: |
| dput(new_parent); |
| dput(old_dentry); |
| dput(new_dentry); |
| return error; |
| } |
| |
| static int sysfs_dir_open(struct inode *inode, struct file *file) |
| { |
| struct dentry * dentry = file->f_path.dentry; |
| struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
| struct sysfs_dirent * sd; |
| |
| sd = sysfs_new_dirent("_DIR_", 0, 0); |
| if (sd) { |
| mutex_lock(&sysfs_mutex); |
| sd->s_parent = sysfs_get(parent_sd); |
| sysfs_link_sibling(sd); |
| mutex_unlock(&sysfs_mutex); |
| } |
| |
| file->private_data = sd; |
| return sd ? 0 : -ENOMEM; |
| } |
| |
| static int sysfs_dir_close(struct inode *inode, struct file *file) |
| { |
| struct sysfs_dirent * cursor = file->private_data; |
| |
| mutex_lock(&sysfs_mutex); |
| sysfs_unlink_sibling(cursor); |
| mutex_unlock(&sysfs_mutex); |
| |
| release_sysfs_dirent(cursor); |
| |
| return 0; |
| } |
| |
| /* 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_readdir(struct file * filp, void * dirent, filldir_t filldir) |
| { |
| struct dentry *dentry = filp->f_path.dentry; |
| struct sysfs_dirent * parent_sd = dentry->d_fsdata; |
| struct sysfs_dirent *cursor = filp->private_data; |
| struct sysfs_dirent **pos; |
| ino_t ino; |
| int i = filp->f_pos; |
| |
| switch (i) { |
| case 0: |
| ino = parent_sd->s_ino; |
| if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) |
| break; |
| filp->f_pos++; |
| i++; |
| /* fallthrough */ |
| case 1: |
| if (parent_sd->s_parent) |
| ino = parent_sd->s_parent->s_ino; |
| else |
| ino = parent_sd->s_ino; |
| if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) |
| break; |
| filp->f_pos++; |
| i++; |
| /* fallthrough */ |
| default: |
| mutex_lock(&sysfs_mutex); |
| |
| pos = &parent_sd->s_children; |
| while (*pos != cursor) |
| pos = &(*pos)->s_sibling; |
| |
| /* unlink cursor */ |
| *pos = cursor->s_sibling; |
| |
| if (filp->f_pos == 2) |
| pos = &parent_sd->s_children; |
| |
| for ( ; *pos; pos = &(*pos)->s_sibling) { |
| struct sysfs_dirent *next = *pos; |
| const char * name; |
| int len; |
| |
| if (!sysfs_type(next)) |
| continue; |
| |
| name = next->s_name; |
| len = strlen(name); |
| ino = next->s_ino; |
| |
| if (filldir(dirent, name, len, filp->f_pos, ino, |
| dt_type(next)) < 0) |
| break; |
| |
| filp->f_pos++; |
| } |
| |
| /* put cursor back in */ |
| cursor->s_sibling = *pos; |
| *pos = cursor; |
| |
| mutex_unlock(&sysfs_mutex); |
| } |
| return 0; |
| } |
| |
| static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) |
| { |
| struct dentry * dentry = file->f_path.dentry; |
| |
| switch (origin) { |
| case 1: |
| offset += file->f_pos; |
| case 0: |
| if (offset >= 0) |
| break; |
| default: |
| return -EINVAL; |
| } |
| if (offset != file->f_pos) { |
| mutex_lock(&sysfs_mutex); |
| |
| file->f_pos = offset; |
| if (file->f_pos >= 2) { |
| struct sysfs_dirent *sd = dentry->d_fsdata; |
| struct sysfs_dirent *cursor = file->private_data; |
| struct sysfs_dirent **pos; |
| loff_t n = file->f_pos - 2; |
| |
| sysfs_unlink_sibling(cursor); |
| |
| pos = &sd->s_children; |
| while (n && *pos) { |
| struct sysfs_dirent *next = *pos; |
| if (sysfs_type(next)) |
| n--; |
| pos = &(*pos)->s_sibling; |
| } |
| |
| cursor->s_sibling = *pos; |
| *pos = cursor; |
| } |
| |
| mutex_unlock(&sysfs_mutex); |
| } |
| |
| return offset; |
| } |
| |
| |
| /** |
| * sysfs_make_shadowed_dir - Setup so a directory can be shadowed |
| * @kobj: object we're creating shadow of. |
| */ |
| |
| int sysfs_make_shadowed_dir(struct kobject *kobj, |
| void * (*follow_link)(struct dentry *, struct nameidata *)) |
| { |
| struct dentry *dentry; |
| struct inode *inode; |
| struct inode_operations *i_op; |
| |
| /* get dentry for @kobj->sd, dentry of a shadowed dir is pinned */ |
| dentry = sysfs_get_dentry(kobj->sd); |
| if (IS_ERR(dentry)) |
| return PTR_ERR(dentry); |
| |
| inode = dentry->d_inode; |
| if (inode->i_op != &sysfs_dir_inode_operations) { |
| dput(dentry); |
| return -EINVAL; |
| } |
| |
| i_op = kmalloc(sizeof(*i_op), GFP_KERNEL); |
| if (!i_op) |
| return -ENOMEM; |
| |
| memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op)); |
| i_op->follow_link = follow_link; |
| |
| /* Locking of inode->i_op? |
| * Since setting i_op is a single word write and they |
| * are atomic we should be ok here. |
| */ |
| inode->i_op = i_op; |
| return 0; |
| } |
| |
| /** |
| * sysfs_create_shadow_dir - create a shadow directory for an object. |
| * @kobj: object we're creating directory for. |
| * |
| * sysfs_make_shadowed_dir must already have been called on this |
| * directory. |
| */ |
| |
| struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj) |
| { |
| struct sysfs_dirent *parent_sd = kobj->sd->s_parent; |
| struct dentry *dir, *parent, *shadow; |
| struct inode *inode; |
| struct sysfs_dirent *sd; |
| struct sysfs_addrm_cxt acxt; |
| |
| dir = sysfs_get_dentry(kobj->sd); |
| if (IS_ERR(dir)) { |
| sd = (void *)dir; |
| goto out; |
| } |
| parent = dir->d_parent; |
| |
| inode = dir->d_inode; |
| sd = ERR_PTR(-EINVAL); |
| if (!sysfs_is_shadowed_inode(inode)) |
| goto out_dput; |
| |
| shadow = d_alloc(parent, &dir->d_name); |
| if (!shadow) |
| goto nomem; |
| |
| sd = sysfs_new_dirent("_SHADOW_", inode->i_mode, SYSFS_DIR); |
| if (!sd) |
| goto nomem; |
| sd->s_elem.dir.kobj = kobj; |
| |
| sysfs_addrm_start(&acxt, parent_sd); |
| |
| /* add but don't link into children list */ |
| sysfs_add_one(&acxt, sd); |
| |
| /* attach and instantiate dentry */ |
| sysfs_attach_dentry(sd, shadow); |
| d_instantiate(shadow, igrab(inode)); |
| inc_nlink(inode); /* tj: synchronization? */ |
| |
| sysfs_addrm_finish(&acxt); |
| |
| dget(shadow); /* Extra count - pin the dentry in core */ |
| |
| goto out_dput; |
| |
| nomem: |
| dput(shadow); |
| sd = ERR_PTR(-ENOMEM); |
| out_dput: |
| dput(dir); |
| out: |
| return sd; |
| } |
| |
| /** |
| * sysfs_remove_shadow_dir - remove an object's directory. |
| * @shadow_sd: sysfs_dirent of shadow directory |
| * |
| * 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_shadow_dir(struct sysfs_dirent *shadow_sd) |
| { |
| __sysfs_remove_dir(shadow_sd); |
| } |
| |
| const struct file_operations sysfs_dir_operations = { |
| .open = sysfs_dir_open, |
| .release = sysfs_dir_close, |
| .llseek = sysfs_dir_lseek, |
| .read = generic_read_dir, |
| .readdir = sysfs_readdir, |
| }; |