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As the size of a directory increases item creation slows down. Optimizing access to s_children removes this bottleneck. dirents are already pinned into the cache, there is no need to scan the s_children list looking for duplicate Items. The configfs_dirent_exists check is moved to a location where it is called only during subsystem initialization. d_lookup will only need to call configfs_lookup in the case where the item in question is not pinned to dcache. The only items not pinned to dcache are attributes. These are placed at the front of the s_children list, whilst pinned items are inserted at the back. configfs_lookup stops scanning when it encounters the first pinned entry in s_children. The assumption of the above optimizations is that there will be few attributes, but potentially many Items in a given directory. Signed-off-by: Seamus Connor <sconnor@purestorage.com> Reviewed-by: Joel Becker <jlbec@evilplan.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
160 lines
4.7 KiB
C
160 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* configfs_internal.h - Internal stuff for configfs
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*
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* Based on sysfs:
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* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
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*
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* configfs Copyright (C) 2005 Oracle. All rights reserved.
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*/
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#ifdef pr_fmt
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#undef pr_fmt
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#endif
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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struct configfs_fragment {
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atomic_t frag_count;
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struct rw_semaphore frag_sem;
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bool frag_dead;
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};
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void put_fragment(struct configfs_fragment *);
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struct configfs_fragment *get_fragment(struct configfs_fragment *);
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struct configfs_dirent {
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atomic_t s_count;
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int s_dependent_count;
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struct list_head s_sibling;
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struct list_head s_children;
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int s_links;
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void * s_element;
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int s_type;
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umode_t s_mode;
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struct dentry * s_dentry;
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struct iattr * s_iattr;
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#ifdef CONFIG_LOCKDEP
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int s_depth;
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#endif
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struct configfs_fragment *s_frag;
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};
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#define CONFIGFS_ROOT 0x0001
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#define CONFIGFS_DIR 0x0002
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#define CONFIGFS_ITEM_ATTR 0x0004
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#define CONFIGFS_ITEM_BIN_ATTR 0x0008
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#define CONFIGFS_ITEM_LINK 0x0020
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#define CONFIGFS_USET_DIR 0x0040
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#define CONFIGFS_USET_DEFAULT 0x0080
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#define CONFIGFS_USET_DROPPING 0x0100
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#define CONFIGFS_USET_IN_MKDIR 0x0200
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#define CONFIGFS_USET_CREATING 0x0400
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#define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)
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#define CONFIGFS_PINNED \
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(CONFIGFS_ROOT | CONFIGFS_DIR | CONFIGFS_ITEM_LINK)
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extern struct mutex configfs_symlink_mutex;
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extern spinlock_t configfs_dirent_lock;
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extern struct kmem_cache *configfs_dir_cachep;
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extern int configfs_is_root(struct config_item *item);
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extern struct inode * configfs_new_inode(umode_t mode, struct configfs_dirent *, struct super_block *);
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extern struct inode *configfs_create(struct dentry *, umode_t mode);
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extern int configfs_create_file(struct config_item *, const struct configfs_attribute *);
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extern int configfs_create_bin_file(struct config_item *,
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const struct configfs_bin_attribute *);
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extern int configfs_make_dirent(struct configfs_dirent *, struct dentry *,
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void *, umode_t, int, struct configfs_fragment *);
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extern int configfs_dirent_is_ready(struct configfs_dirent *);
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extern const unsigned char * configfs_get_name(struct configfs_dirent *sd);
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extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent);
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extern int configfs_setattr(struct mnt_idmap *idmap,
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struct dentry *dentry, struct iattr *iattr);
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extern struct dentry *configfs_pin_fs(void);
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extern void configfs_release_fs(void);
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extern const struct file_operations configfs_dir_operations;
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extern const struct file_operations configfs_file_operations;
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extern const struct file_operations configfs_bin_file_operations;
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extern const struct inode_operations configfs_dir_inode_operations;
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extern const struct inode_operations configfs_root_inode_operations;
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extern const struct inode_operations configfs_symlink_inode_operations;
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extern const struct dentry_operations configfs_dentry_ops;
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extern int configfs_symlink(struct mnt_idmap *idmap,
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struct inode *dir, struct dentry *dentry,
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const char *symname);
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extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
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int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
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struct dentry *dentry, char *body);
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static inline struct config_item * to_item(struct dentry * dentry)
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{
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struct configfs_dirent * sd = dentry->d_fsdata;
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return ((struct config_item *) sd->s_element);
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}
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static inline struct configfs_attribute * to_attr(struct dentry * dentry)
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{
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struct configfs_dirent * sd = dentry->d_fsdata;
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return ((struct configfs_attribute *) sd->s_element);
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}
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static inline struct configfs_bin_attribute *to_bin_attr(struct dentry *dentry)
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{
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struct configfs_attribute *attr = to_attr(dentry);
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return container_of(attr, struct configfs_bin_attribute, cb_attr);
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}
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static inline struct config_item *configfs_get_config_item(struct dentry *dentry)
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{
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struct config_item * item = NULL;
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spin_lock(&dentry->d_lock);
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if (!d_unhashed(dentry)) {
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struct configfs_dirent * sd = dentry->d_fsdata;
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item = config_item_get(sd->s_element);
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}
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spin_unlock(&dentry->d_lock);
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return item;
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}
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static inline void release_configfs_dirent(struct configfs_dirent * sd)
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{
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if (!(sd->s_type & CONFIGFS_ROOT)) {
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kfree(sd->s_iattr);
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put_fragment(sd->s_frag);
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kmem_cache_free(configfs_dir_cachep, sd);
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}
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}
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static inline struct configfs_dirent * configfs_get(struct configfs_dirent * sd)
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{
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if (sd) {
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WARN_ON(!atomic_read(&sd->s_count));
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atomic_inc(&sd->s_count);
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}
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return sd;
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}
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static inline void configfs_put(struct configfs_dirent * sd)
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{
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WARN_ON(!atomic_read(&sd->s_count));
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if (atomic_dec_and_test(&sd->s_count))
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release_configfs_dirent(sd);
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}
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