make to_shrink_list() return whether it has moved dentry to list

... and make it check the refcount for being zero in addition to
dentry not being on a shrink list already.  Simplifies the callers...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/dcache.c b/fs/dcache.c
index 40031b806b739fa5d113d049055cf5971f79a006..7a0c8349b5a1a72765b4d540aba283cb5b874c01 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -988,14 +988,17 @@ void d_make_discardable(struct dentry *dentry)
 }
 EXPORT_SYMBOL(d_make_discardable);
 
-static void to_shrink_list(struct dentry *dentry, struct list_head *list)
+static bool to_shrink_list(struct dentry *dentry, struct list_head *list)
 __must_hold(&dentry->d_lock)
 {
-       if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) {
+       if (likely(!dentry->d_lockref.count &&
+           !(dentry->d_flags & DCACHE_SHRINK_LIST))) {
                if (dentry->d_flags & DCACHE_LRU_LIST)
                        d_lru_del(dentry);
                d_shrink_add(dentry, list);
+               return true;
        }
+       return false;
 }
 
 void dput_to_list(struct dentry *dentry, struct list_head *list)
@@ -1180,8 +1183,7 @@ struct dentry *d_find_alias_rcu(struct inode *inode)
 void d_dispose_if_unused(struct dentry *dentry, struct list_head *dispose)
 {
        spin_lock(&dentry->d_lock);
-       if (!dentry->d_lockref.count)
-               to_shrink_list(dentry, dispose);
+       to_shrink_list(dentry, dispose);
        spin_unlock(&dentry->d_lock);
 }
 EXPORT_SYMBOL(d_dispose_if_unused);
@@ -1589,11 +1591,9 @@ static enum d_walk_ret select_collect(void *_data, struct dentry *dentry)
        if (data->start == dentry)
                goto out;
 
-       if (!dentry->d_lockref.count) {
+       if (dentry->d_lockref.count <= 0) {
                to_shrink_list(dentry, &data->dispose);
                data->found++;
-       } else if (dentry->d_lockref.count < 0) {
-               data->found++;
        }
        /*
         * We can return to the caller if we have found some (this
@@ -1623,17 +1623,12 @@ static enum d_walk_ret select_collect2(void *_data, struct dentry *dentry)
        if (data->start == dentry)
                goto out;
 
-       if (!dentry->d_lockref.count) {
-               if (dentry->d_flags & DCACHE_SHRINK_LIST) {
+       if (dentry->d_lockref.count <= 0) {
+               if (!to_shrink_list(dentry, &data->dispose)) {
                        rcu_read_lock();
                        data->victim = dentry;
                        return D_WALK_QUIT;
                }
-               to_shrink_list(dentry, &data->dispose);
-       } else if (dentry->d_lockref.count < 0) {
-               rcu_read_lock();
-               data->victim = dentry;
-               return D_WALK_QUIT;
        }
        /*
         * We can return to the caller if we have found some (this