[PATCH v2 18/18] autofs: change get_next_positive_dentry() to NOT accept NULL for start-up

[NeilBrown]

From: NeilBrown <neil@xxxxxxxxxx>

Rather than passing NULL to get_next_positive_dentry() to first time
round, change callers to use a for loop which does the dget() explicitly
to start the loop.

I think this makes the code clearer.  Looking at
get_next_positive_dentry() it isn't immediately obvious what that code
is doing there.

Signed-off-by: NeilBrown <neil@xxxxxxxxxx>
---
 fs/autofs/expire.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/autofs/expire.c b/fs/autofs/expire.c
index 277d9129754e..2a1844ba48c6 100644
--- a/fs/autofs/expire.c
+++ b/fs/autofs/expire.c
@@ -83,9 +83,6 @@ static struct dentry *get_next_positive_dentry(struct dentry *prev,
 {
 	struct dentry *ret = NULL;
 
-	if (prev == NULL)
-		return dget(root);
-
 	while ((ret = d_scan_positives(prev, ret, 0)) == NULL &&
 	       prev != root) {
 		ret = prev;
@@ -148,7 +145,7 @@ static int autofs_tree_busy(struct vfsmount *mnt,
 		return 1;
 
 	p = NULL;
-	while ((p = get_next_positive_dentry(p, top))) {
+	for (p = dget(top); p; p = get_next_positive_dentry(p, top)) {
 		pr_debug("dentry %p %pd\n", p, p);
 
 		/*
@@ -201,8 +198,7 @@ static struct dentry *autofs_check_leaves(struct vfsmount *mnt,
 
 	pr_debug("parent %p %pd\n", parent, parent);
 
-	p = NULL;
-	while ((p = get_next_positive_dentry(p, parent))) {
+	for (p = dget(parent); p; p = get_next_positive_dentry(p, parent)) {
 		pr_debug("dentry %p %pd\n", p, p);
 
 		if (d_mountpoint(p)) {
-- 
2.50.0.107.gf914562f5916.dirty