vfs: make it possible to access the dentry hash/len as one 64-bit entry

This allows comparing hash and len in one operation on 64-bit
architectures.  Right now only __d_lookup_rcu() takes advantage of this,
since that is the case we care most about.

The use of anonymous struct/unions hides the alternate 64-bit approach
from most users, the exception being a few cases where we initialize a
'struct qstr' with a static initializer.  This makes the problematic
cases use a new QSTR_INIT() helper function for that (but initializing
just the name pointer with a "{ .name = xyzzy }" initializer remains
valid, as does just copying another qstr structure).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 18d08f5db53a..f86ec27a4230 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -68,7 +68,7 @@ struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct na
 
 int dcache_dir_open(struct inode *inode, struct file *file)
 {
-        static struct qstr cursor_name = {.len = 1, .name = "."};
+        static struct qstr cursor_name = QSTR_INIT(".", 1);
 
         file->private_data = d_alloc(file->f_path.dentry, &cursor_name);
 
@@ -225,7 +225,7 @@ struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
         struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
         struct dentry *dentry;
         struct inode *root;
-        struct qstr d_name = {.name = name, .len = strlen(name)};
+        struct qstr d_name = QSTR_INIT(name, strlen(name));
 
         if (IS_ERR(s))
                 return ERR_CAST(s);