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Commit e17a5765 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
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proc: do translation + unlink atomically at remove_proc_entry() 



remove_proc_entry() does

	lock
	lookup parent
	unlock
	lock
	unlink proc entry from lists
	unlock

which can be made bit more correct by doing parent translation + unlink
without dropping lock.

Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5748150e

fs/proc/generic.c

+19 −12
Original line number Original line Diff line number Diff line
@@ -291,19 +291,17 @@ static const struct inode_operations proc_file_inode_operations = { 
 * returns the struct proc_dir_entry for "/proc/tty/driver", and

 * returns the struct proc_dir_entry for "/proc/tty/driver", and

 * returns "serial" in residual.

 * returns "serial" in residual.

 */

 */

static int xlate_proc_name(const char *name,

static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,

			   struct proc_dir_entry **ret, const char **residual)

			     const char **residual)

{

{

	const char     		*cp = name, *next;

	const char     		*cp = name, *next;

	struct proc_dir_entry	*de;

	struct proc_dir_entry	*de;

	int			len;

	int			len;

	int 			rtn = 0;





	de = *ret;

	de = *ret;

	if (!de)

	if (!de)

		de = &proc_root;

		de = &proc_root;





	spin_lock(&proc_subdir_lock);

	while (1) {

	while (1) {

		next = strchr(cp, '/');

		next = strchr(cp, '/');

		if (!next)

		if (!next)
@@ -314,17 +312,24 @@ static int xlate_proc_name(const char *name, 
			if (proc_match(len, cp, de))

			if (proc_match(len, cp, de))

				break;

				break;

		}

		}

		if (!de) {

		if (!de)

			rtn = -ENOENT;

			return -ENOENT;

			goto out;

		}

		cp += len + 1;

		cp += len + 1;

	}

	}

	*residual = cp;

	*residual = cp;

	*ret = de;

	*ret = de;

out:

	return 0;

}



static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,

			   const char **residual)

{

	int rv;



	spin_lock(&proc_subdir_lock);

	rv = __xlate_proc_name(name, ret, residual);

	spin_unlock(&proc_subdir_lock);

	spin_unlock(&proc_subdir_lock);

	return rtn;

	return rv;

}

}





static DEFINE_IDA(proc_inum_ida);

static DEFINE_IDA(proc_inum_ida);
@@ -797,11 +802,13 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent) 
	const char *fn = name;

	const char *fn = name;

	int len;

	int len;





	if (xlate_proc_name(name, &parent, &fn) != 0)

	spin_lock(&proc_subdir_lock);

	if (__xlate_proc_name(name, &parent, &fn) != 0) {

		spin_unlock(&proc_subdir_lock);

		return;

		return;

	}

	len = strlen(fn);

	len = strlen(fn);





	spin_lock(&proc_subdir_lock);

	for (p = &parent->subdir; *p; p=&(*p)->next ) {

	for (p = &parent->subdir; *p; p=&(*p)->next ) {

		if (proc_match(len, fn, *p)) {

		if (proc_match(len, fn, *p)) {

			de = *p;

			de = *p;