sysfs: Remove support for tagged directories with untagged members.

Now that /sys/class/net/bonding_masters is implemented as a tagged sysfs
file we can remove support for untagged files in tagged directories.

This change removes any ambiguity of what a NULL namespace value
means.  A NULL namespace parameter after this patch means
that we are talking about an untagged sysfs dirent.

This makes the sysfs code much less prone to mistakes when during
maintenance.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

fs/sysfs/dir.c

@@ -543,7 +543,7 @@ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
 	struct sysfs_dirent *sd;
 
 	for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
-		if (ns && sd->s_ns && (sd->s_ns != ns))
+		if (sd->s_ns != ns)
 			continue;
 		if (!strcmp(sd->s_name, name))
 			return sd;
@@ -885,7 +885,7 @@ static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
 		while (pos && (ino > pos->s_ino))
 			pos = pos->s_sibling;
 	}
-	while (pos && pos->s_ns && pos->s_ns != ns)
+	while (pos && pos->s_ns != ns)
 		pos = pos->s_sibling;
 	return pos;
 }
@@ -896,7 +896,7 @@ static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
 	pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
 	if (pos)
 		pos = pos->s_sibling;
-	while (pos && pos->s_ns && pos->s_ns != ns)
+	while (pos && pos->s_ns != ns)
 		pos = pos->s_sibling;
 	return pos;
 }

fs/sysfs/inode.c

@@ -336,8 +336,6 @@ int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const void *ns, const cha
 	sysfs_addrm_start(&acxt, dir_sd);
 
 	sd = sysfs_find_dirent(dir_sd, ns, name);
-	if (sd && (sd->s_ns != ns))
-		sd = NULL;
 	if (sd)
 		sysfs_remove_one(&acxt, sd);