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proc_setup_self() and proc_setup_thread_self() are only called from proc_fill_super() which is before the filesystem is "live". So there is no need to lock the root directory when adding "self" and "thread-self". This is clear from simple_fill_super() which provides similar functionality for other filesystems and does not lock anything. The locking is not harmful, except that it may be confusing to a reader. As part of an effort to centralise all locking for directories for name-based operations (prior to changing some locking rules), it is simplest to remove the locking here. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neil@brown.name> Link: https://patch.msgid.link/20260224222542.3458677-3-neilb@ownmail.net Signed-off-by: Christian Brauner <brauner@kernel.org>
67 lines
1.5 KiB
C
67 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/cache.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/pid_namespace.h>
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#include "internal.h"
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/*
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* /proc/self:
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*/
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static const char *proc_self_get_link(struct dentry *dentry,
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struct inode *inode,
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struct delayed_call *done)
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{
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struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
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pid_t tgid = task_tgid_nr_ns(current, ns);
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char *name;
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if (!tgid)
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return ERR_PTR(-ENOENT);
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/* max length of unsigned int in decimal + NULL term */
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name = kmalloc(10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
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if (unlikely(!name))
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return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
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sprintf(name, "%u", tgid);
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set_delayed_call(done, kfree_link, name);
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return name;
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}
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static const struct inode_operations proc_self_inode_operations = {
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.get_link = proc_self_get_link,
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};
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unsigned self_inum __ro_after_init;
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int proc_setup_self(struct super_block *s)
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{
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struct dentry *self;
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int ret = -ENOMEM;
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self = d_alloc_name(s->s_root, "self");
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if (self) {
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struct inode *inode = new_inode(s);
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if (inode) {
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inode->i_ino = self_inum;
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simple_inode_init_ts(inode);
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inode->i_mode = S_IFLNK | S_IRWXUGO;
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inode->i_uid = GLOBAL_ROOT_UID;
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inode->i_gid = GLOBAL_ROOT_GID;
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inode->i_op = &proc_self_inode_operations;
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d_make_persistent(self, inode);
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ret = 0;
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}
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dput(self);
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}
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if (ret)
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pr_err("proc_fill_super: can't allocate /proc/self\n");
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return ret;
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}
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void __init proc_self_init(void)
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{
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proc_alloc_inum(&self_inum);
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}
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