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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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99b7623380
Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy as correctly noted at bug #12454. Someone can lookup entry with NULL ->owner, thus not pinning enything, and release it later resulting in module refcount underflow. We can keep ->owner and supply it at registration time like ->proc_fops and ->data. But this leaves ->owner as easy-manipulative field (just one C assignment) and somebody will forget to unpin previous/pin current module when switching ->owner. ->proc_fops is declared as "const" which should give some thoughts. ->read_proc/->write_proc were just fixed to not require ->owner for protection. rmmod'ed directories will be empty and return "." and ".." -- no harm. And directories with tricky enough readdir and lookup shouldn't be modular. We definitely don't want such modular code. Removing ->owner will also make PDE smaller. So, let's nuke it. Kudos to Jeff Layton for reminding about this, let's say, oversight. http://bugzilla.kernel.org/show_bug.cgi?id=12454 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
110 lines
2.8 KiB
C
110 lines
2.8 KiB
C
/*
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* Copyright (C) International Business Machines Corp., 2000-2004
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* Portions Copyright (C) Christoph Hellwig, 2001-2002
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/fs.h>
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#include <linux/ctype.h>
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#include <linux/module.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <asm/uaccess.h>
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#include "jfs_incore.h"
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#include "jfs_filsys.h"
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#include "jfs_debug.h"
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#ifdef PROC_FS_JFS /* see jfs_debug.h */
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static struct proc_dir_entry *base;
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#ifdef CONFIG_JFS_DEBUG
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static int jfs_loglevel_proc_show(struct seq_file *m, void *v)
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{
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seq_printf(m, "%d\n", jfsloglevel);
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return 0;
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}
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static int jfs_loglevel_proc_open(struct inode *inode, struct file *file)
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{
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return single_open(file, jfs_loglevel_proc_show, NULL);
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}
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static ssize_t jfs_loglevel_proc_write(struct file *file,
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const char __user *buffer, size_t count, loff_t *ppos)
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{
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char c;
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if (get_user(c, buffer))
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return -EFAULT;
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/* yes, I know this is an ASCIIism. --hch */
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if (c < '0' || c > '9')
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return -EINVAL;
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jfsloglevel = c - '0';
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return count;
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}
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static const struct file_operations jfs_loglevel_proc_fops = {
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.owner = THIS_MODULE,
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.open = jfs_loglevel_proc_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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.write = jfs_loglevel_proc_write,
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};
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#endif
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static struct {
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const char *name;
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const struct file_operations *proc_fops;
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} Entries[] = {
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#ifdef CONFIG_JFS_STATISTICS
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{ "lmstats", &jfs_lmstats_proc_fops, },
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{ "txstats", &jfs_txstats_proc_fops, },
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{ "xtstat", &jfs_xtstat_proc_fops, },
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{ "mpstat", &jfs_mpstat_proc_fops, },
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#endif
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#ifdef CONFIG_JFS_DEBUG
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{ "TxAnchor", &jfs_txanchor_proc_fops, },
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{ "loglevel", &jfs_loglevel_proc_fops }
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#endif
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};
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#define NPROCENT ARRAY_SIZE(Entries)
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void jfs_proc_init(void)
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{
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int i;
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if (!(base = proc_mkdir("fs/jfs", NULL)))
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return;
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for (i = 0; i < NPROCENT; i++)
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proc_create(Entries[i].name, 0, base, Entries[i].proc_fops);
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}
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void jfs_proc_clean(void)
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{
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int i;
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if (base) {
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for (i = 0; i < NPROCENT; i++)
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remove_proc_entry(Entries[i].name, base);
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remove_proc_entry("fs/jfs", NULL);
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}
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}
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#endif /* PROC_FS_JFS */
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