proc_sys_fill_cache(): switch to d_alloc_parallel()

make it usable with directory locked shared

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

1 files changed, 8 insertions, 7 deletions

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index fe5b6e6c4671..d69e2385862c 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -627,18 +627,19 @@ static bool proc_sys_fill_cache(struct file *file,
 
         child = d_lookup(dir, &qname);
         if (!child) {
-                child = d_alloc(dir, &qname);
-                if (child) {
+                DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+                child = d_alloc_parallel(dir, &qname, &wq);
+                if (IS_ERR(child))
+                        return false;
+                if (d_in_lookup(child)) {
                         inode = proc_sys_make_inode(dir->d_sb, head, table);
                         if (!inode) {
+                                d_lookup_done(child);
                                 dput(child);
                                 return false;
-                        } else {
-                                d_set_d_op(child, &proc_sys_dentry_operations);
-                                d_add(child, inode);
                         }
-                } else {
-                        return false;
+                        d_set_d_op(child, &proc_sys_dentry_operations);
+                        d_add(child, inode);
                 }
         }
         inode = d_inode(child);