Commit 33d6dce6 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

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: default avatarSerge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent 4f326c00

fs/proc/generic.c

+13 −13
Original line number Diff line number Diff line
@@ -350,14 +350,14 @@ static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */ 
 * Return an inode number between PROC_DYNAMIC_FIRST and

 * 0xffffffff, or zero on failure.

 */

static unsigned int get_inode_number(void)

int proc_alloc_inum(unsigned int *inum)

{

	unsigned int i;

	int error;



retry:

	if (ida_pre_get(&proc_inum_ida, GFP_KERNEL) == 0)

		return 0;

	if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))

		return -ENOMEM;



	spin_lock(&proc_inum_lock);

	error = ida_get_new(&proc_inum_ida, &i);
@@ -365,18 +365,19 @@ retry: 
	if (error == -EAGAIN)

		goto retry;

	else if (error)

		return 0;

		return error;



	if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {

		spin_lock(&proc_inum_lock);

		ida_remove(&proc_inum_ida, i);

		spin_unlock(&proc_inum_lock);

		return 0;

		return -ENOSPC;

	}

	return PROC_DYNAMIC_FIRST + i;

	*inum = PROC_DYNAMIC_FIRST + i;

	return 0;

}



static void release_inode_number(unsigned int inum)

void proc_free_inum(unsigned int inum)

{

	spin_lock(&proc_inum_lock);

	ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
@@ -554,13 +555,12 @@ static const struct inode_operations proc_dir_inode_operations = { 


static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)

{

	unsigned int i;

	struct proc_dir_entry *tmp;

	int ret;

	

	i = get_inode_number();

	if (i == 0)

		return -EAGAIN;

	dp->low_ino = i;

	ret = proc_alloc_inum(&dp->low_ino);

	if (ret)

		return ret;



	if (S_ISDIR(dp->mode)) {

		if (dp->proc_iops == NULL) {
@@ -764,7 +764,7 @@ EXPORT_SYMBOL(proc_create_data); 


static void free_proc_entry(struct proc_dir_entry *de)

{

	release_inode_number(de->low_ino);

	proc_free_inum(de->low_ino);



	if (S_ISLNK(de->mode))

		kfree(de->data);

include/linux/proc_fs.h

+10 −0
Original line number Diff line number Diff line
@@ -176,6 +176,8 @@ extern struct proc_dir_entry *proc_net_mkdir(struct net *net, const char *name, 
extern struct file *proc_ns_fget(int fd);

extern bool proc_ns_inode(struct inode *inode);



extern int proc_alloc_inum(unsigned int *pino);

extern void proc_free_inum(unsigned int inum);

#else



#define proc_net_fops_create(net, name, mode, fops)  ({ (void)(mode), NULL; })
@@ -235,6 +237,14 @@ static inline bool proc_ns_inode(struct inode *inode) 
	return false;

}



static inline int proc_alloc_inum(unsigned int *inum)

{

	*inum = 1;

	return 0;

}

static inline void proc_free_inum(unsigned int inum)

{

}

#endif /* CONFIG_PROC_FS */



#if !defined(CONFIG_PROC_KCORE)

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