forked from luck/tmp_suning_uos_patched
0c73f18b7d
Make sysfs_dirent use singly linked list for its tree structure. sysfs_link_sibling() and sysfs_unlink_sibling() functions are added to handle simpler cases. It adds some complexity and cpu cycle overhead but reduced memory footprint is worthwhile on big machines. This change reduces the sizeof sysfs_dirent from 104 to 88 on 64bit and from 60 to 52 on 32bit. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
939 lines
20 KiB
C
939 lines
20 KiB
C
/*
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* dir.c - Operations for sysfs directories.
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*/
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#undef DEBUG
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/module.h>
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#include <linux/kobject.h>
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#include <linux/namei.h>
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#include <linux/idr.h>
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#include <linux/completion.h>
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#include <asm/semaphore.h>
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#include "sysfs.h"
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DECLARE_RWSEM(sysfs_rename_sem);
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spinlock_t sysfs_lock = SPIN_LOCK_UNLOCKED;
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spinlock_t kobj_sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;
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static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;
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static DEFINE_IDA(sysfs_ino_ida);
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/**
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* sysfs_link_sibling - link sysfs_dirent into sibling list
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* @sd: sysfs_dirent of interest
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*
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* Link @sd into its sibling list which starts from
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* sd->s_parent->s_children.
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*
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* Locking:
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* mutex_lock(sd->s_parent->dentry->d_inode->i_mutex)
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*/
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static void sysfs_link_sibling(struct sysfs_dirent *sd)
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{
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struct sysfs_dirent *parent_sd = sd->s_parent;
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BUG_ON(sd->s_sibling);
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sd->s_sibling = parent_sd->s_children;
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parent_sd->s_children = sd;
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}
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/**
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* sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
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* @sd: sysfs_dirent of interest
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*
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* Unlink @sd from its sibling list which starts from
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* sd->s_parent->s_children.
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*
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* Locking:
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* mutex_lock(sd->s_parent->dentry->d_inode->i_mutex)
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*/
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static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
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{
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struct sysfs_dirent **pos;
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for (pos = &sd->s_parent->s_children; *pos; pos = &(*pos)->s_sibling) {
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if (*pos == sd) {
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*pos = sd->s_sibling;
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sd->s_sibling = NULL;
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break;
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}
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}
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}
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/**
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* sysfs_get_active - get an active reference to sysfs_dirent
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* @sd: sysfs_dirent to get an active reference to
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*
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* Get an active reference of @sd. This function is noop if @sd
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* is NULL.
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*
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* RETURNS:
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* Pointer to @sd on success, NULL on failure.
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*/
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struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
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{
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if (unlikely(!sd))
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return NULL;
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while (1) {
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int v, t;
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v = atomic_read(&sd->s_active);
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if (unlikely(v < 0))
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return NULL;
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t = atomic_cmpxchg(&sd->s_active, v, v + 1);
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if (likely(t == v))
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return sd;
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if (t < 0)
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return NULL;
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cpu_relax();
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}
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}
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/**
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* sysfs_put_active - put an active reference to sysfs_dirent
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* @sd: sysfs_dirent to put an active reference to
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*
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* Put an active reference to @sd. This function is noop if @sd
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* is NULL.
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*/
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void sysfs_put_active(struct sysfs_dirent *sd)
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{
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struct completion *cmpl;
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int v;
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if (unlikely(!sd))
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return;
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v = atomic_dec_return(&sd->s_active);
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if (likely(v != SD_DEACTIVATED_BIAS))
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return;
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/* atomic_dec_return() is a mb(), we'll always see the updated
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* sd->s_sibling.
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*/
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cmpl = (void *)sd->s_sibling;
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complete(cmpl);
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}
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/**
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* sysfs_get_active_two - get active references to sysfs_dirent and parent
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* @sd: sysfs_dirent of interest
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*
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* Get active reference to @sd and its parent. Parent's active
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* reference is grabbed first. This function is noop if @sd is
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* NULL.
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*
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* RETURNS:
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* Pointer to @sd on success, NULL on failure.
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*/
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struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd)
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{
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if (sd) {
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if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
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return NULL;
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if (unlikely(!sysfs_get_active(sd))) {
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sysfs_put_active(sd->s_parent);
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return NULL;
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}
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}
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return sd;
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}
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/**
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* sysfs_put_active_two - put active references to sysfs_dirent and parent
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* @sd: sysfs_dirent of interest
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*
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* Put active references to @sd and its parent. This function is
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* noop if @sd is NULL.
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*/
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void sysfs_put_active_two(struct sysfs_dirent *sd)
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{
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if (sd) {
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sysfs_put_active(sd);
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sysfs_put_active(sd->s_parent);
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}
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}
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/**
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* sysfs_deactivate - deactivate sysfs_dirent
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* @sd: sysfs_dirent to deactivate
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*
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* Deny new active references and drain existing ones.
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*/
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void sysfs_deactivate(struct sysfs_dirent *sd)
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{
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DECLARE_COMPLETION_ONSTACK(wait);
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int v;
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BUG_ON(sd->s_sibling);
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sd->s_sibling = (void *)&wait;
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/* atomic_add_return() is a mb(), put_active() will always see
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* the updated sd->s_sibling.
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*/
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v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
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if (v != SD_DEACTIVATED_BIAS)
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wait_for_completion(&wait);
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sd->s_sibling = NULL;
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}
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static int sysfs_alloc_ino(ino_t *pino)
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{
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int ino, rc;
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retry:
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spin_lock(&sysfs_ino_lock);
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rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
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spin_unlock(&sysfs_ino_lock);
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if (rc == -EAGAIN) {
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if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
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goto retry;
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rc = -ENOMEM;
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}
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*pino = ino;
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return rc;
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}
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static void sysfs_free_ino(ino_t ino)
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{
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spin_lock(&sysfs_ino_lock);
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ida_remove(&sysfs_ino_ida, ino);
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spin_unlock(&sysfs_ino_lock);
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}
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void release_sysfs_dirent(struct sysfs_dirent * sd)
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{
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struct sysfs_dirent *parent_sd;
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repeat:
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parent_sd = sd->s_parent;
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if (sd->s_type & SYSFS_KOBJ_LINK)
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sysfs_put(sd->s_elem.symlink.target_sd);
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if (sd->s_type & SYSFS_COPY_NAME)
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kfree(sd->s_name);
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kfree(sd->s_iattr);
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sysfs_free_ino(sd->s_ino);
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kmem_cache_free(sysfs_dir_cachep, sd);
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sd = parent_sd;
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if (sd && atomic_dec_and_test(&sd->s_count))
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goto repeat;
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}
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static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
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{
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struct sysfs_dirent * sd = dentry->d_fsdata;
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if (sd) {
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/* sd->s_dentry is protected with sysfs_lock. This
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* allows sysfs_drop_dentry() to dereference it.
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*/
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spin_lock(&sysfs_lock);
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/* The dentry might have been deleted or another
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* lookup could have happened updating sd->s_dentry to
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* point the new dentry. Ignore if it isn't pointing
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* to this dentry.
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*/
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if (sd->s_dentry == dentry)
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sd->s_dentry = NULL;
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spin_unlock(&sysfs_lock);
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sysfs_put(sd);
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}
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iput(inode);
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}
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static struct dentry_operations sysfs_dentry_ops = {
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.d_iput = sysfs_d_iput,
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};
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struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
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{
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char *dup_name = NULL;
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struct sysfs_dirent *sd = NULL;
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if (type & SYSFS_COPY_NAME) {
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name = dup_name = kstrdup(name, GFP_KERNEL);
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if (!name)
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goto err_out;
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}
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sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
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if (!sd)
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goto err_out;
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if (sysfs_alloc_ino(&sd->s_ino))
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goto err_out;
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atomic_set(&sd->s_count, 1);
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atomic_set(&sd->s_active, 0);
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atomic_set(&sd->s_event, 1);
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sd->s_name = name;
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sd->s_mode = mode;
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sd->s_type = type;
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return sd;
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err_out:
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kfree(dup_name);
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kmem_cache_free(sysfs_dir_cachep, sd);
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return NULL;
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}
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static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry)
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{
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dentry->d_op = &sysfs_dentry_ops;
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dentry->d_fsdata = sysfs_get(sd);
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/* protect sd->s_dentry against sysfs_d_iput */
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spin_lock(&sysfs_lock);
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sd->s_dentry = dentry;
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spin_unlock(&sysfs_lock);
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d_rehash(dentry);
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}
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void sysfs_attach_dirent(struct sysfs_dirent *sd,
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struct sysfs_dirent *parent_sd, struct dentry *dentry)
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{
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if (dentry)
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sysfs_attach_dentry(sd, dentry);
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if (parent_sd) {
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sd->s_parent = sysfs_get(parent_sd);
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sysfs_link_sibling(sd);
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}
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}
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/*
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*
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* Return -EEXIST if there is already a sysfs element with the same name for
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* the same parent.
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*
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* called with parent inode's i_mutex held
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*/
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int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
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const unsigned char *new)
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{
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struct sysfs_dirent * sd;
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for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) {
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if (sd->s_type) {
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if (strcmp(sd->s_name, new))
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continue;
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else
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return -EEXIST;
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}
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}
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return 0;
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}
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static int create_dir(struct kobject *kobj, struct dentry *parent,
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const char *name, struct dentry **p_dentry)
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{
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int error;
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umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
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struct dentry *dentry;
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struct inode *inode;
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struct sysfs_dirent *sd;
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mutex_lock(&parent->d_inode->i_mutex);
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/* allocate */
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dentry = lookup_one_len(name, parent, strlen(name));
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if (IS_ERR(dentry)) {
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error = PTR_ERR(dentry);
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goto out_unlock;
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}
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error = -EEXIST;
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if (dentry->d_inode)
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goto out_dput;
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error = -ENOMEM;
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sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
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if (!sd)
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goto out_drop;
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sd->s_elem.dir.kobj = kobj;
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inode = sysfs_get_inode(sd);
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if (!inode)
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goto out_sput;
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if (inode->i_state & I_NEW) {
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inode->i_op = &sysfs_dir_inode_operations;
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inode->i_fop = &sysfs_dir_operations;
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/* directory inodes start off with i_nlink == 2 (for ".") */
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inc_nlink(inode);
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}
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/* link in */
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error = -EEXIST;
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if (sysfs_dirent_exist(parent->d_fsdata, name))
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goto out_iput;
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sysfs_instantiate(dentry, inode);
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inc_nlink(parent->d_inode);
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sysfs_attach_dirent(sd, parent->d_fsdata, dentry);
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*p_dentry = dentry;
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error = 0;
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goto out_unlock; /* pin directory dentry in core */
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out_iput:
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iput(inode);
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out_sput:
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sysfs_put(sd);
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out_drop:
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d_drop(dentry);
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out_dput:
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dput(dentry);
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out_unlock:
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mutex_unlock(&parent->d_inode->i_mutex);
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return error;
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}
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|
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int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
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{
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return create_dir(k,k->dentry,n,d);
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}
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/**
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* sysfs_create_dir - create a directory for an object.
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* @kobj: object we're creating directory for.
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* @shadow_parent: parent parent object.
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*/
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int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent)
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{
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struct dentry * dentry = NULL;
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struct dentry * parent;
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int error = 0;
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BUG_ON(!kobj);
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if (shadow_parent)
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parent = shadow_parent;
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else if (kobj->parent)
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parent = kobj->parent->dentry;
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else if (sysfs_mount && sysfs_mount->mnt_sb)
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parent = sysfs_mount->mnt_sb->s_root;
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else
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return -EFAULT;
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error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
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if (!error)
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kobj->dentry = dentry;
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return error;
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}
|
|
|
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static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
|
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struct nameidata *nd)
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{
|
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struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
|
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struct sysfs_dirent * sd;
|
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struct inode *inode;
|
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int found = 0;
|
|
|
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for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) {
|
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if ((sd->s_type & SYSFS_NOT_PINNED) &&
|
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!strcmp(sd->s_name, dentry->d_name.name)) {
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found = 1;
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break;
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}
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}
|
|
|
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/* no such entry */
|
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if (!found)
|
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return NULL;
|
|
|
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/* attach dentry and inode */
|
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inode = sysfs_get_inode(sd);
|
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if (!inode)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (inode->i_state & I_NEW) {
|
|
/* initialize inode according to type */
|
|
if (sd->s_type & SYSFS_KOBJ_ATTR) {
|
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inode->i_size = PAGE_SIZE;
|
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inode->i_fop = &sysfs_file_operations;
|
|
} else if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
|
|
struct bin_attribute *bin_attr =
|
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sd->s_elem.bin_attr.bin_attr;
|
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inode->i_size = bin_attr->size;
|
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inode->i_fop = &bin_fops;
|
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} else if (sd->s_type & SYSFS_KOBJ_LINK)
|
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inode->i_op = &sysfs_symlink_inode_operations;
|
|
}
|
|
|
|
sysfs_instantiate(dentry, inode);
|
|
sysfs_attach_dentry(sd, dentry);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
const struct inode_operations sysfs_dir_inode_operations = {
|
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.lookup = sysfs_lookup,
|
|
.setattr = sysfs_setattr,
|
|
};
|
|
|
|
static void remove_dir(struct dentry * d)
|
|
{
|
|
struct dentry *parent = d->d_parent;
|
|
struct sysfs_dirent *sd = d->d_fsdata;
|
|
|
|
mutex_lock(&parent->d_inode->i_mutex);
|
|
|
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sysfs_unlink_sibling(sd);
|
|
|
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pr_debug(" o %s removing done (%d)\n",d->d_name.name,
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atomic_read(&d->d_count));
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|
|
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mutex_unlock(&parent->d_inode->i_mutex);
|
|
|
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sysfs_drop_dentry(sd);
|
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sysfs_deactivate(sd);
|
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sysfs_put(sd);
|
|
}
|
|
|
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void sysfs_remove_subdir(struct dentry * d)
|
|
{
|
|
remove_dir(d);
|
|
}
|
|
|
|
|
|
static void __sysfs_remove_dir(struct dentry *dentry)
|
|
{
|
|
struct sysfs_dirent *removed = NULL;
|
|
struct sysfs_dirent *parent_sd;
|
|
struct sysfs_dirent **pos;
|
|
|
|
if (!dentry)
|
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return;
|
|
|
|
pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
|
|
mutex_lock(&dentry->d_inode->i_mutex);
|
|
parent_sd = dentry->d_fsdata;
|
|
pos = &parent_sd->s_children;
|
|
while (*pos) {
|
|
struct sysfs_dirent *sd = *pos;
|
|
|
|
if (sd->s_type && (sd->s_type & SYSFS_NOT_PINNED)) {
|
|
*pos = sd->s_sibling;
|
|
sd->s_sibling = removed;
|
|
removed = sd;
|
|
} else
|
|
pos = &(*pos)->s_sibling;
|
|
}
|
|
mutex_unlock(&dentry->d_inode->i_mutex);
|
|
|
|
while (removed) {
|
|
struct sysfs_dirent *sd = removed;
|
|
|
|
removed = sd->s_sibling;
|
|
sd->s_sibling = NULL;
|
|
|
|
sysfs_drop_dentry(sd);
|
|
sysfs_deactivate(sd);
|
|
sysfs_put(sd);
|
|
}
|
|
|
|
remove_dir(dentry);
|
|
}
|
|
|
|
/**
|
|
* 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 dentry *d = kobj->dentry;
|
|
|
|
spin_lock(&kobj_sysfs_assoc_lock);
|
|
kobj->dentry = NULL;
|
|
spin_unlock(&kobj_sysfs_assoc_lock);
|
|
|
|
__sysfs_remove_dir(d);
|
|
}
|
|
|
|
int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent,
|
|
const char *new_name)
|
|
{
|
|
struct sysfs_dirent *sd = kobj->dentry->d_fsdata;
|
|
struct sysfs_dirent *parent_sd = new_parent->d_fsdata;
|
|
struct dentry *new_dentry;
|
|
char *dup_name;
|
|
int error;
|
|
|
|
if (!new_parent)
|
|
return -EFAULT;
|
|
|
|
down_write(&sysfs_rename_sem);
|
|
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 (kobj->dentry->d_parent->d_inode != new_parent->d_inode ||
|
|
new_dentry->d_parent->d_inode != new_parent->d_inode ||
|
|
new_dentry == kobj->dentry)
|
|
goto out_dput;
|
|
|
|
error = -EEXIST;
|
|
if (new_dentry->d_inode)
|
|
goto out_dput;
|
|
|
|
/* 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_free;
|
|
|
|
kfree(sd->s_name);
|
|
sd->s_name = new_name;
|
|
|
|
/* move under the new parent */
|
|
d_add(new_dentry, NULL);
|
|
d_move(kobj->dentry, new_dentry);
|
|
|
|
sysfs_unlink_sibling(sd);
|
|
sysfs_get(parent_sd);
|
|
sysfs_put(sd->s_parent);
|
|
sd->s_parent = parent_sd;
|
|
sysfs_link_sibling(sd);
|
|
|
|
error = 0;
|
|
goto out_unlock;
|
|
|
|
out_free:
|
|
kfree(dup_name);
|
|
out_drop:
|
|
d_drop(new_dentry);
|
|
out_dput:
|
|
dput(new_dentry);
|
|
out_unlock:
|
|
mutex_unlock(&new_parent->d_inode->i_mutex);
|
|
up_write(&sysfs_rename_sem);
|
|
return error;
|
|
}
|
|
|
|
int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
|
|
{
|
|
struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;
|
|
struct sysfs_dirent *new_parent_sd, *sd;
|
|
int error;
|
|
|
|
old_parent_dentry = kobj->parent ?
|
|
kobj->parent->dentry : sysfs_mount->mnt_sb->s_root;
|
|
new_parent_dentry = new_parent ?
|
|
new_parent->dentry : sysfs_mount->mnt_sb->s_root;
|
|
|
|
if (old_parent_dentry->d_inode == new_parent_dentry->d_inode)
|
|
return 0; /* nothing to move */
|
|
again:
|
|
mutex_lock(&old_parent_dentry->d_inode->i_mutex);
|
|
if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {
|
|
mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
|
|
goto again;
|
|
}
|
|
|
|
new_parent_sd = new_parent_dentry->d_fsdata;
|
|
sd = kobj->dentry->d_fsdata;
|
|
|
|
new_dentry = lookup_one_len(kobj->name, new_parent_dentry,
|
|
strlen(kobj->name));
|
|
if (IS_ERR(new_dentry)) {
|
|
error = PTR_ERR(new_dentry);
|
|
goto out;
|
|
} else
|
|
error = 0;
|
|
d_add(new_dentry, NULL);
|
|
d_move(kobj->dentry, new_dentry);
|
|
dput(new_dentry);
|
|
|
|
/* Remove from old parent's list and insert into new parent's list. */
|
|
sysfs_unlink_sibling(sd);
|
|
sysfs_get(new_parent_sd);
|
|
sysfs_put(sd->s_parent);
|
|
sd->s_parent = new_parent_sd;
|
|
sysfs_link_sibling(sd);
|
|
|
|
out:
|
|
mutex_unlock(&new_parent_dentry->d_inode->i_mutex);
|
|
mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
|
|
|
|
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;
|
|
|
|
mutex_lock(&dentry->d_inode->i_mutex);
|
|
sd = sysfs_new_dirent("_DIR_", 0, 0);
|
|
if (sd)
|
|
sysfs_attach_dirent(sd, parent_sd, NULL);
|
|
mutex_unlock(&dentry->d_inode->i_mutex);
|
|
|
|
file->private_data = sd;
|
|
return sd ? 0 : -ENOMEM;
|
|
}
|
|
|
|
static int sysfs_dir_close(struct inode *inode, struct file *file)
|
|
{
|
|
struct dentry * dentry = file->f_path.dentry;
|
|
struct sysfs_dirent * cursor = file->private_data;
|
|
|
|
mutex_lock(&dentry->d_inode->i_mutex);
|
|
sysfs_unlink_sibling(cursor);
|
|
mutex_unlock(&dentry->d_inode->i_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:
|
|
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 (!next->s_type)
|
|
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;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
|
|
{
|
|
struct dentry * dentry = file->f_path.dentry;
|
|
|
|
mutex_lock(&dentry->d_inode->i_mutex);
|
|
switch (origin) {
|
|
case 1:
|
|
offset += file->f_pos;
|
|
case 0:
|
|
if (offset >= 0)
|
|
break;
|
|
default:
|
|
mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
|
|
return -EINVAL;
|
|
}
|
|
if (offset != file->f_pos) {
|
|
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 (next->s_type)
|
|
n--;
|
|
pos = &(*pos)->s_sibling;
|
|
}
|
|
|
|
cursor->s_sibling = *pos;
|
|
*pos = cursor;
|
|
}
|
|
}
|
|
mutex_unlock(&dentry->d_inode->i_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 inode *inode;
|
|
struct inode_operations *i_op;
|
|
|
|
inode = kobj->dentry->d_inode;
|
|
if (inode->i_op != &sysfs_dir_inode_operations)
|
|
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 dentry *sysfs_create_shadow_dir(struct kobject *kobj)
|
|
{
|
|
struct dentry *dir = kobj->dentry;
|
|
struct inode *inode = dir->d_inode;
|
|
struct dentry *parent = dir->d_parent;
|
|
struct sysfs_dirent *parent_sd = parent->d_fsdata;
|
|
struct dentry *shadow;
|
|
struct sysfs_dirent *sd;
|
|
|
|
shadow = ERR_PTR(-EINVAL);
|
|
if (!sysfs_is_shadowed_inode(inode))
|
|
goto out;
|
|
|
|
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;
|
|
/* point to parent_sd but don't attach to it */
|
|
sd->s_parent = sysfs_get(parent_sd);
|
|
sysfs_attach_dirent(sd, NULL, shadow);
|
|
|
|
d_instantiate(shadow, igrab(inode));
|
|
inc_nlink(inode);
|
|
inc_nlink(parent->d_inode);
|
|
|
|
dget(shadow); /* Extra count - pin the dentry in core */
|
|
|
|
out:
|
|
return shadow;
|
|
nomem:
|
|
dput(shadow);
|
|
shadow = ERR_PTR(-ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
/**
|
|
* sysfs_remove_shadow_dir - remove an object's directory.
|
|
* @shadow: dentry 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 dentry *shadow)
|
|
{
|
|
__sysfs_remove_dir(shadow);
|
|
}
|
|
|
|
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,
|
|
};
|