sysfs, kernfs: move dir core code to fs/kernfs/dir.c (fd7b9f7b) · Commits · e / devices / android_kernel_oneplus_sm8150

fs/kernfs/dir.c

+988 −0

Original line number	Diff line number	Diff line
		@@ -7,3 +7,991 @@
		*
		* This file is released under the GPLv2.
		*/

		#include <linux/fs.h>
		#include <linux/namei.h>
		#include <linux/idr.h>
		#include <linux/slab.h>
		#include <linux/security.h>
		#include <linux/hash.h>

		#include "kernfs-internal.h"

		DEFINE_MUTEX(sysfs_mutex);

		#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
		* @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 char name, const void ns)
		{
		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 char *name,
		const void ns, 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_name, left->s_ns,
		right);
		}

		/**
		* sysfs_link_sibling - 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);
		}

		/**
		* 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;

		if (!atomic_inc_unless_negative(&sd->s_active))
		return NULL;

		if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
		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 (sd->s_flags & SYSFS_FLAG_LOCKDEP)
		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);
		}

		/**
		* kernfs_get - get a reference count on a sysfs_dirent
		* @sd: the target sysfs_dirent
		*/
		void kernfs_get(struct sysfs_dirent *sd)
		{
		if (sd) {
		WARN_ON(!atomic_read(&sd->s_count));
		atomic_inc(&sd->s_count);
		}
		}
		EXPORT_SYMBOL_GPL(kernfs_get);

		/**
		* kernfs_put - put a reference count on a sysfs_dirent
		* @sd: the target sysfs_dirent
		*
		* Put a reference count of @sd and destroy it if it reached zero.
		*/
		void kernfs_put(struct sysfs_dirent *sd)
		{
		struct sysfs_dirent *parent_sd;

		if (!sd \|\| !atomic_dec_and_test(&sd->s_count))
		return;
		repeat:
		/* Moving/renaming is always done while holding reference.
		* sd->s_parent won't change beneath us.
		*/
		parent_sd = sd->s_parent;

		WARN(!(sd->s_flags & SYSFS_FLAG_REMOVED),
		"sysfs: free using entry: %s/%s\n",
		parent_sd ? parent_sd->s_name : "", sd->s_name);

		if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
		kernfs_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;
		}
		EXPORT_SYMBOL_GPL(kernfs_put);

		static int sysfs_dentry_delete(const struct dentry *dentry)
		{
		struct sysfs_dirent *sd = dentry->d_fsdata;
		return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED));
		}

		static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
		{
		struct sysfs_dirent *sd;

		if (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;

		/* The sysfs dirent has been moved to a different namespace */
		if (sd->s_parent && (sd->s_parent->s_flags & SYSFS_FLAG_NS) &&
		sysfs_info(dentry->d_sb)->ns != sd->s_ns)
		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.
		*/
		mutex_unlock(&sysfs_mutex);

		/* 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 (check_submounts_and_drop(dentry) != 0)
		goto out_valid;

		return 0;
		}

		static void sysfs_dentry_release(struct dentry *dentry)
		{
		kernfs_put(dentry->d_fsdata);
		}

		const struct dentry_operations sysfs_dentry_ops = {
		.d_revalidate = sysfs_dentry_revalidate,
		.d_delete = sysfs_dentry_delete,
		.d_release = sysfs_dentry_release,
		};

		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 \| SYSFS_FLAG_REMOVED;

		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
		*
		* 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)
		__acquires(sysfs_mutex)
		{
		memset(acxt, 0, sizeof(*acxt));

		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
		* @parent_sd: the parent sysfs_dirent to add @sd to
		*
		* 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
		* 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)
		{
		bool has_ns = parent_sd->s_flags & SYSFS_FLAG_NS;
		struct sysfs_inode_attrs *ps_iattr;
		int ret;

		if (has_ns != (bool)sd->s_ns) {
		WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
		has_ns ? "required" : "invalid",
		parent_sd->s_name, sd->s_name);
		return -EINVAL;
		}

		if (sysfs_type(parent_sd) != SYSFS_DIR)
		return -EINVAL;

		sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns);
		sd->s_parent = parent_sd;
		kernfs_get(parent_sd);

		ret = sysfs_link_sibling(sd);
		if (ret)
		return ret;

		/* Update timestamps on the parent */
		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;
		}

		/* Mark the entry added into directory tree */
		sd->s_flags &= ~SYSFS_FLAG_REMOVED;

		return 0;
		}

		/**
		* 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);
		kernfs_put(sd);
		}
		}

		/**
		* kernfs_find_ns - find sysfs_dirent with the given name
		* @parent: 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. Returns pointer to
		* the found sysfs_dirent on success, %NULL on failure.
		*/
		static struct sysfs_dirent kernfs_find_ns(struct sysfs_dirent parent,
		const unsigned char *name,
		const void *ns)
		{
		struct rb_node *node = parent->s_dir.children.rb_node;
		bool has_ns = parent->s_flags & SYSFS_FLAG_NS;
		unsigned int hash;

		lockdep_assert_held(&sysfs_mutex);

		if (has_ns != (bool)ns) {
		WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
		has_ns ? "required" : "invalid",
		parent->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;
		}

		/**
		* kernfs_find_and_get_ns - find and get sysfs_dirent with the given name
		* @parent: 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 and get a reference
		* if found. This function may sleep and returns pointer to the found
		* sysfs_dirent on success, %NULL on failure.
		*/
		struct sysfs_dirent kernfs_find_and_get_ns(struct sysfs_dirent parent,
		const char name, const void ns)
		{
		struct sysfs_dirent *sd;

		mutex_lock(&sysfs_mutex);
		sd = kernfs_find_ns(parent, name, ns);
		kernfs_get(sd);
		mutex_unlock(&sysfs_mutex);

		return sd;
		}
		EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);

		/**
		* kernfs_create_dir_ns - create a directory
		* @parent: parent in which to create a new directory
		* @name: name of the new directory
		* @priv: opaque data associated with the new directory
		* @ns: optional namespace tag of the directory
		*
		* Returns the created node on success, ERR_PTR() value on failure.
		*/
		struct sysfs_dirent kernfs_create_dir_ns(struct sysfs_dirent parent,
		const char name, void priv,
		const void *ns)
		{
		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 ERR_PTR(-ENOMEM);

		sd->s_ns = ns;
		sd->priv = priv;

		/* link in */
		sysfs_addrm_start(&acxt);
		rc = sysfs_add_one(&acxt, sd, parent);
		sysfs_addrm_finish(&acxt);

		if (!rc)
		return sd;

		kernfs_put(sd);
		return ERR_PTR(rc);
		}

		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;
		const void *ns = NULL;

		mutex_lock(&sysfs_mutex);

		if (parent_sd->s_flags & SYSFS_FLAG_NS)
		ns = sysfs_info(dir->i_sb)->ns;

		sd = kernfs_find_ns(parent_sd, dentry->d_name.name, ns);

		/* no such entry */
		if (!sd) {
		ret = ERR_PTR(-ENOENT);
		goto out_unlock;
		}
		kernfs_get(sd);
		dentry->d_fsdata = 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 __kernfs_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);
		}

		/**
		* kernfs_remove - remove a sysfs_dirent recursively
		* @sd: the sysfs_dirent to remove
		*
		* Remove @sd along with all its subdirectories and files.
		*/
		void kernfs_remove(struct sysfs_dirent *sd)
		{
		struct sysfs_addrm_cxt acxt;

		sysfs_addrm_start(&acxt);
		__kernfs_remove(&acxt, sd);
		sysfs_addrm_finish(&acxt);
		}

		/**
		* kernfs_remove_by_name_ns - 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 kernfs_remove_by_name_ns(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 = kernfs_find_ns(dir_sd, name, ns);
		if (sd)
		__kernfs_remove(&acxt, sd);

		sysfs_addrm_finish(&acxt);

		if (sd)
		return 0;
		else
		return -ENOENT;
		}

		/**
		* kernfs_rename_ns - move and rename a kernfs_node
		* @sd: target node
		* @new_parent: new parent to put @sd under
		* @new_name: new name
		* @new_ns: new namespace tag
		*/
		int kernfs_rename_ns(struct sysfs_dirent sd, struct sysfs_dirent new_parent,
		const char new_name, const void new_ns)
		{
		int error;

		mutex_lock(&sysfs_mutex);

		error = 0;
		if ((sd->s_parent == new_parent) && (sd->s_ns == new_ns) &&
		(strcmp(sd->s_name, new_name) == 0))
		goto out; /* nothing to rename */

		error = -EEXIST;
		if (kernfs_find_ns(new_parent, 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);
		kernfs_get(new_parent);
		kernfs_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;
		sysfs_link_sibling(sd);

		error = 0;
		out:
		mutex_unlock(&sysfs_mutex);
		return error;
		}

		/**
		* kernfs_enable_ns - enable namespace under a directory
		* @sd: directory of interest, should be empty
		*
		* This is to be called right after @sd is created to enable namespace
		* under it. All children of @sd must have non-NULL namespace tags and
		* only the ones which match the super_block's tag will be visible.
		*/
		void kernfs_enable_ns(struct sysfs_dirent *sd)
		{
		WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR);
		WARN_ON_ONCE(!RB_EMPTY_ROOT(&sd->s_dir.children));
		sd->s_flags \|= SYSFS_FLAG_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)
		{
		kernfs_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;
		kernfs_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;
		const void *ns = NULL;

		if (!dir_emit_dots(file, ctx))
		return 0;
		mutex_lock(&sysfs_mutex);

		if (parent_sd->s_flags & SYSFS_FLAG_NS)
		ns = sysfs_info(dentry->d_sb)->ns;

		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 = pos;
		kernfs_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,
		};

fs/kernfs/kernfs-internal.h

+17 −0

File changed.

Preview size limit exceeded, changes collapsed.

fs/sysfs/dir.c

+0 −986

File changed.

Preview size limit exceeded, changes collapsed.

fs/sysfs/sysfs.h

+0 −13

Original line number	Diff line number	Diff line
		@@ -34,22 +34,9 @@ extern struct kmem_cache *sysfs_dir_cachep;
		/*
		* dir.c
		*/
		extern struct mutex sysfs_mutex;
		extern spinlock_t sysfs_symlink_target_lock;
		extern const struct dentry_operations sysfs_dentry_ops;

		extern const struct file_operations sysfs_dir_operations;
		extern const struct inode_operations sysfs_dir_inode_operations;

		struct sysfs_dirent sysfs_get_active(struct sysfs_dirent sd);
		void sysfs_put_active(struct sysfs_dirent *sd);
		void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt);
		void sysfs_warn_dup(struct sysfs_dirent parent, const char name);
		int sysfs_add_one(struct sysfs_addrm_cxt acxt, struct sysfs_dirent sd,
		struct sysfs_dirent *parent_sd);
		void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);

		struct sysfs_dirent sysfs_new_dirent(const char name, umode_t mode, int type);

		/*
		* file.c