proc: Generalize proc inode allocation
Generalize the proc inode allocation so that it can be used without having to having to create a proc_dir_entry. This will allow namespace file descriptors to remain light weight entitities but still have the same inode number when the backing namespace is the same. Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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@ -350,14 +350,14 @@ static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
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* Return an inode number between PROC_DYNAMIC_FIRST and
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* 0xffffffff, or zero on failure.
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*/
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static unsigned int get_inode_number(void)
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int proc_alloc_inum(unsigned int *inum)
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{
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unsigned int i;
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int error;
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retry:
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if (ida_pre_get(&proc_inum_ida, GFP_KERNEL) == 0)
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return 0;
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if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
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return -ENOMEM;
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spin_lock(&proc_inum_lock);
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error = ida_get_new(&proc_inum_ida, &i);
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@ -365,18 +365,19 @@ retry:
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if (error == -EAGAIN)
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goto retry;
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else if (error)
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return 0;
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return error;
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if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
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spin_lock(&proc_inum_lock);
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ida_remove(&proc_inum_ida, i);
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spin_unlock(&proc_inum_lock);
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return 0;
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return -ENOSPC;
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}
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return PROC_DYNAMIC_FIRST + i;
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*inum = PROC_DYNAMIC_FIRST + i;
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return 0;
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}
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static void release_inode_number(unsigned int inum)
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void proc_free_inum(unsigned int inum)
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{
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spin_lock(&proc_inum_lock);
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ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
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@ -554,13 +555,12 @@ static const struct inode_operations proc_dir_inode_operations = {
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static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
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{
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unsigned int i;
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struct proc_dir_entry *tmp;
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int ret;
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i = get_inode_number();
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if (i == 0)
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return -EAGAIN;
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dp->low_ino = i;
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ret = proc_alloc_inum(&dp->low_ino);
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if (ret)
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return ret;
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if (S_ISDIR(dp->mode)) {
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if (dp->proc_iops == NULL) {
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@ -764,7 +764,7 @@ EXPORT_SYMBOL(proc_create_data);
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static void free_proc_entry(struct proc_dir_entry *de)
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{
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release_inode_number(de->low_ino);
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proc_free_inum(de->low_ino);
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if (S_ISLNK(de->mode))
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kfree(de->data);
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@ -176,6 +176,8 @@ extern struct proc_dir_entry *proc_net_mkdir(struct net *net, const char *name,
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extern struct file *proc_ns_fget(int fd);
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extern bool proc_ns_inode(struct inode *inode);
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extern int proc_alloc_inum(unsigned int *pino);
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extern void proc_free_inum(unsigned int inum);
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#else
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#define proc_net_fops_create(net, name, mode, fops) ({ (void)(mode), NULL; })
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@ -235,6 +237,14 @@ static inline bool proc_ns_inode(struct inode *inode)
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return false;
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}
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static inline int proc_alloc_inum(unsigned int *inum)
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{
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*inum = 1;
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return 0;
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}
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static inline void proc_free_inum(unsigned int inum)
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{
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}
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#endif /* CONFIG_PROC_FS */
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#if !defined(CONFIG_PROC_KCORE)
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