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5b2f2bd62e
This include is not needed (fs/sysfs/file.c builds just fine without it). Remove it. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
561 lines
14 KiB
C
561 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* fs/sysfs/file.c - sysfs regular (text) file implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
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*
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* Please see Documentation/filesystems/sysfs.txt for more information.
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*/
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#include <linux/module.h>
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#include <linux/kobject.h>
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <linux/mutex.h>
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#include <linux/seq_file.h>
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#include "sysfs.h"
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/*
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* Determine ktype->sysfs_ops for the given kernfs_node. This function
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* must be called while holding an active reference.
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*/
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static const struct sysfs_ops *sysfs_file_ops(struct kernfs_node *kn)
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{
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struct kobject *kobj = kn->parent->priv;
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if (kn->flags & KERNFS_LOCKDEP)
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lockdep_assert_held(kn);
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return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
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}
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/*
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* Reads on sysfs are handled through seq_file, which takes care of hairy
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* details like buffering and seeking. The following function pipes
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* sysfs_ops->show() result through seq_file.
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*/
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static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
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{
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struct kernfs_open_file *of = sf->private;
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struct kobject *kobj = of->kn->parent->priv;
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const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
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ssize_t count;
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char *buf;
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/* acquire buffer and ensure that it's >= PAGE_SIZE and clear */
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count = seq_get_buf(sf, &buf);
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if (count < PAGE_SIZE) {
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seq_commit(sf, -1);
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return 0;
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}
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memset(buf, 0, PAGE_SIZE);
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/*
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* Invoke show(). Control may reach here via seq file lseek even
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* if @ops->show() isn't implemented.
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*/
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if (ops->show) {
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count = ops->show(kobj, of->kn->priv, buf);
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if (count < 0)
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return count;
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}
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/*
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* The code works fine with PAGE_SIZE return but it's likely to
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* indicate truncated result or overflow in normal use cases.
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*/
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if (count >= (ssize_t)PAGE_SIZE) {
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printk("fill_read_buffer: %pS returned bad count\n",
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ops->show);
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/* Try to struggle along */
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count = PAGE_SIZE - 1;
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}
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seq_commit(sf, count);
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return 0;
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}
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static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf,
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size_t count, loff_t pos)
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{
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struct bin_attribute *battr = of->kn->priv;
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struct kobject *kobj = of->kn->parent->priv;
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loff_t size = file_inode(of->file)->i_size;
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if (!count)
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return 0;
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if (size) {
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if (pos >= size)
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return 0;
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if (pos + count > size)
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count = size - pos;
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}
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if (!battr->read)
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return -EIO;
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return battr->read(of->file, kobj, battr, buf, pos, count);
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}
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/* kernfs read callback for regular sysfs files with pre-alloc */
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static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
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size_t count, loff_t pos)
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{
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const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
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struct kobject *kobj = of->kn->parent->priv;
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ssize_t len;
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/*
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* If buf != of->prealloc_buf, we don't know how
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* large it is, so cannot safely pass it to ->show
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*/
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if (WARN_ON_ONCE(buf != of->prealloc_buf))
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return 0;
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len = ops->show(kobj, of->kn->priv, buf);
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if (len < 0)
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return len;
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if (pos) {
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if (len <= pos)
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return 0;
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len -= pos;
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memmove(buf, buf + pos, len);
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}
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return min_t(ssize_t, count, len);
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}
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/* kernfs write callback for regular sysfs files */
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static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
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size_t count, loff_t pos)
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{
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const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
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struct kobject *kobj = of->kn->parent->priv;
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if (!count)
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return 0;
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return ops->store(kobj, of->kn->priv, buf, count);
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}
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/* kernfs write callback for bin sysfs files */
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static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
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size_t count, loff_t pos)
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{
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struct bin_attribute *battr = of->kn->priv;
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struct kobject *kobj = of->kn->parent->priv;
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loff_t size = file_inode(of->file)->i_size;
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if (size) {
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if (size <= pos)
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return -EFBIG;
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count = min_t(ssize_t, count, size - pos);
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}
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if (!count)
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return 0;
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if (!battr->write)
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return -EIO;
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return battr->write(of->file, kobj, battr, buf, pos, count);
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}
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static int sysfs_kf_bin_mmap(struct kernfs_open_file *of,
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struct vm_area_struct *vma)
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{
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struct bin_attribute *battr = of->kn->priv;
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struct kobject *kobj = of->kn->parent->priv;
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return battr->mmap(of->file, kobj, battr, vma);
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}
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void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr)
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{
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struct kernfs_node *kn = kobj->sd, *tmp;
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if (kn && dir)
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kn = kernfs_find_and_get(kn, dir);
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else
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kernfs_get(kn);
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if (kn && attr) {
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tmp = kernfs_find_and_get(kn, attr);
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kernfs_put(kn);
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kn = tmp;
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}
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if (kn) {
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kernfs_notify(kn);
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kernfs_put(kn);
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}
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}
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EXPORT_SYMBOL_GPL(sysfs_notify);
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static const struct kernfs_ops sysfs_file_kfops_empty = {
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};
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static const struct kernfs_ops sysfs_file_kfops_ro = {
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.seq_show = sysfs_kf_seq_show,
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};
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static const struct kernfs_ops sysfs_file_kfops_wo = {
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.write = sysfs_kf_write,
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};
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static const struct kernfs_ops sysfs_file_kfops_rw = {
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.seq_show = sysfs_kf_seq_show,
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.write = sysfs_kf_write,
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};
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static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
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.read = sysfs_kf_read,
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.prealloc = true,
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};
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static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
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.write = sysfs_kf_write,
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.prealloc = true,
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};
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static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
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.read = sysfs_kf_read,
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.write = sysfs_kf_write,
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.prealloc = true,
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};
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static const struct kernfs_ops sysfs_bin_kfops_ro = {
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.read = sysfs_kf_bin_read,
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};
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static const struct kernfs_ops sysfs_bin_kfops_wo = {
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.write = sysfs_kf_bin_write,
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};
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static const struct kernfs_ops sysfs_bin_kfops_rw = {
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.read = sysfs_kf_bin_read,
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.write = sysfs_kf_bin_write,
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};
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static const struct kernfs_ops sysfs_bin_kfops_mmap = {
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.read = sysfs_kf_bin_read,
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.write = sysfs_kf_bin_write,
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.mmap = sysfs_kf_bin_mmap,
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};
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int sysfs_add_file_mode_ns(struct kernfs_node *parent,
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const struct attribute *attr, bool is_bin,
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umode_t mode, kuid_t uid, kgid_t gid, const void *ns)
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{
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struct lock_class_key *key = NULL;
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const struct kernfs_ops *ops;
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struct kernfs_node *kn;
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loff_t size;
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if (!is_bin) {
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struct kobject *kobj = parent->priv;
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const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;
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/* every kobject with an attribute needs a ktype assigned */
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if (WARN(!sysfs_ops, KERN_ERR
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"missing sysfs attribute operations for kobject: %s\n",
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kobject_name(kobj)))
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return -EINVAL;
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if (sysfs_ops->show && sysfs_ops->store) {
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if (mode & SYSFS_PREALLOC)
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ops = &sysfs_prealloc_kfops_rw;
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else
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ops = &sysfs_file_kfops_rw;
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} else if (sysfs_ops->show) {
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if (mode & SYSFS_PREALLOC)
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ops = &sysfs_prealloc_kfops_ro;
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else
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ops = &sysfs_file_kfops_ro;
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} else if (sysfs_ops->store) {
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if (mode & SYSFS_PREALLOC)
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ops = &sysfs_prealloc_kfops_wo;
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else
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ops = &sysfs_file_kfops_wo;
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} else
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ops = &sysfs_file_kfops_empty;
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size = PAGE_SIZE;
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} else {
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struct bin_attribute *battr = (void *)attr;
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if (battr->mmap)
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ops = &sysfs_bin_kfops_mmap;
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else if (battr->read && battr->write)
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ops = &sysfs_bin_kfops_rw;
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else if (battr->read)
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ops = &sysfs_bin_kfops_ro;
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else if (battr->write)
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ops = &sysfs_bin_kfops_wo;
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else
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ops = &sysfs_file_kfops_empty;
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size = battr->size;
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}
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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if (!attr->ignore_lockdep)
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key = attr->key ?: (struct lock_class_key *)&attr->skey;
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#endif
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kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid,
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size, ops, (void *)attr, ns, key);
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if (IS_ERR(kn)) {
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if (PTR_ERR(kn) == -EEXIST)
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sysfs_warn_dup(parent, attr->name);
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return PTR_ERR(kn);
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}
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return 0;
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}
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/**
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* sysfs_create_file_ns - create an attribute file for an object with custom ns
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* @kobj: object we're creating for
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* @attr: attribute descriptor
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* @ns: namespace the new file should belong to
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*/
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int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
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const void *ns)
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{
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kuid_t uid;
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kgid_t gid;
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if (WARN_ON(!kobj || !kobj->sd || !attr))
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return -EINVAL;
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kobject_get_ownership(kobj, &uid, &gid);
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return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode,
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uid, gid, ns);
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}
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EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
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int sysfs_create_files(struct kobject *kobj, const struct attribute * const *ptr)
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{
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int err = 0;
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int i;
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for (i = 0; ptr[i] && !err; i++)
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err = sysfs_create_file(kobj, ptr[i]);
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if (err)
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while (--i >= 0)
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sysfs_remove_file(kobj, ptr[i]);
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return err;
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}
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EXPORT_SYMBOL_GPL(sysfs_create_files);
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/**
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* sysfs_add_file_to_group - add an attribute file to a pre-existing group.
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* @kobj: object we're acting for.
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* @attr: attribute descriptor.
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* @group: group name.
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*/
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int sysfs_add_file_to_group(struct kobject *kobj,
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const struct attribute *attr, const char *group)
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{
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struct kernfs_node *parent;
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kuid_t uid;
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kgid_t gid;
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int error;
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if (group) {
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parent = kernfs_find_and_get(kobj->sd, group);
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} else {
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parent = kobj->sd;
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kernfs_get(parent);
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}
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if (!parent)
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return -ENOENT;
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kobject_get_ownership(kobj, &uid, &gid);
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error = sysfs_add_file_mode_ns(parent, attr, false,
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attr->mode, uid, gid, NULL);
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kernfs_put(parent);
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return error;
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}
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EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
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/**
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* sysfs_chmod_file - update the modified mode value on an object attribute.
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* @kobj: object we're acting for.
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* @attr: attribute descriptor.
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* @mode: file permissions.
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*
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*/
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int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
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umode_t mode)
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{
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struct kernfs_node *kn;
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struct iattr newattrs;
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int rc;
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kn = kernfs_find_and_get(kobj->sd, attr->name);
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if (!kn)
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return -ENOENT;
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newattrs.ia_mode = (mode & S_IALLUGO) | (kn->mode & ~S_IALLUGO);
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newattrs.ia_valid = ATTR_MODE;
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rc = kernfs_setattr(kn, &newattrs);
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kernfs_put(kn);
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return rc;
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}
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EXPORT_SYMBOL_GPL(sysfs_chmod_file);
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/**
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* sysfs_break_active_protection - break "active" protection
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* @kobj: The kernel object @attr is associated with.
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* @attr: The attribute to break the "active" protection for.
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*
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* With sysfs, just like kernfs, deletion of an attribute is postponed until
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* all active .show() and .store() callbacks have finished unless this function
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* is called. Hence this function is useful in methods that implement self
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* deletion.
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*/
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struct kernfs_node *sysfs_break_active_protection(struct kobject *kobj,
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const struct attribute *attr)
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{
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struct kernfs_node *kn;
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kobject_get(kobj);
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kn = kernfs_find_and_get(kobj->sd, attr->name);
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if (kn)
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kernfs_break_active_protection(kn);
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return kn;
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}
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EXPORT_SYMBOL_GPL(sysfs_break_active_protection);
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/**
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* sysfs_unbreak_active_protection - restore "active" protection
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* @kn: Pointer returned by sysfs_break_active_protection().
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*
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* Undo the effects of sysfs_break_active_protection(). Since this function
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* calls kernfs_put() on the kernfs node that corresponds to the 'attr'
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* argument passed to sysfs_break_active_protection() that attribute may have
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* been removed between the sysfs_break_active_protection() and
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* sysfs_unbreak_active_protection() calls, it is not safe to access @kn after
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* this function has returned.
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*/
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void sysfs_unbreak_active_protection(struct kernfs_node *kn)
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{
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struct kobject *kobj = kn->parent->priv;
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kernfs_unbreak_active_protection(kn);
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kernfs_put(kn);
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kobject_put(kobj);
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}
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EXPORT_SYMBOL_GPL(sysfs_unbreak_active_protection);
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/**
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* sysfs_remove_file_ns - remove an object attribute with a custom ns tag
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* @kobj: object we're acting for
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* @attr: attribute descriptor
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* @ns: namespace tag of the file to remove
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*
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* Hash the attribute name and namespace tag and kill the victim.
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*/
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void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
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const void *ns)
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{
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struct kernfs_node *parent = kobj->sd;
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kernfs_remove_by_name_ns(parent, attr->name, ns);
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}
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EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
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/**
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* sysfs_remove_file_self - remove an object attribute from its own method
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* @kobj: object we're acting for
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* @attr: attribute descriptor
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*
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* See kernfs_remove_self() for details.
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*/
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bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
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{
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struct kernfs_node *parent = kobj->sd;
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struct kernfs_node *kn;
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bool ret;
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kn = kernfs_find_and_get(parent, attr->name);
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if (WARN_ON_ONCE(!kn))
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return false;
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ret = kernfs_remove_self(kn);
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kernfs_put(kn);
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return ret;
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}
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void sysfs_remove_files(struct kobject *kobj, const struct attribute * const *ptr)
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{
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int i;
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for (i = 0; ptr[i]; i++)
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sysfs_remove_file(kobj, ptr[i]);
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}
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EXPORT_SYMBOL_GPL(sysfs_remove_files);
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/**
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* sysfs_remove_file_from_group - remove an attribute file from a group.
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* @kobj: object we're acting for.
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* @attr: attribute descriptor.
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* @group: group name.
|
|
*/
|
|
void sysfs_remove_file_from_group(struct kobject *kobj,
|
|
const struct attribute *attr, const char *group)
|
|
{
|
|
struct kernfs_node *parent;
|
|
|
|
if (group) {
|
|
parent = kernfs_find_and_get(kobj->sd, group);
|
|
} else {
|
|
parent = kobj->sd;
|
|
kernfs_get(parent);
|
|
}
|
|
|
|
if (parent) {
|
|
kernfs_remove_by_name(parent, attr->name);
|
|
kernfs_put(parent);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
|
|
|
|
/**
|
|
* sysfs_create_bin_file - create binary file for object.
|
|
* @kobj: object.
|
|
* @attr: attribute descriptor.
|
|
*/
|
|
int sysfs_create_bin_file(struct kobject *kobj,
|
|
const struct bin_attribute *attr)
|
|
{
|
|
kuid_t uid;
|
|
kgid_t gid;
|
|
|
|
if (WARN_ON(!kobj || !kobj->sd || !attr))
|
|
return -EINVAL;
|
|
|
|
kobject_get_ownership(kobj, &uid, &gid);
|
|
return sysfs_add_file_mode_ns(kobj->sd, &attr->attr, true,
|
|
attr->attr.mode, uid, gid, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
|
|
|
|
/**
|
|
* sysfs_remove_bin_file - remove binary file for object.
|
|
* @kobj: object.
|
|
* @attr: attribute descriptor.
|
|
*/
|
|
void sysfs_remove_bin_file(struct kobject *kobj,
|
|
const struct bin_attribute *attr)
|
|
{
|
|
kernfs_remove_by_name(kobj->sd, attr->attr.name);
|
|
}
|
|
EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
|