ramfs, hugetlbfs, mqueue: set DCACHE_DONTCACHE

makes simple_lookup() slightly cheaper there - no need for
simple_lookup() to set the flag and we want it on everything
on those anyway.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Author: Al Viro

fs/hugetlbfs/inode.c

@@ -1433,6 +1433,7 @@ hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
 	sb->s_magic = HUGETLBFS_MAGIC;
 	sb->s_op = &hugetlbfs_ops;
+	sb->s_d_flags = DCACHE_DONTCACHE;
 	sb->s_time_gran = 1;
 
 	/*

fs/ramfs/inode.c

@@ -269,6 +269,7 @@ static int ramfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_blocksize_bits	= PAGE_SHIFT;
 	sb->s_magic		= RAMFS_MAGIC;
 	sb->s_op		= &ramfs_ops;
+	sb->s_d_flags		= DCACHE_DONTCACHE;
 	sb->s_time_gran		= 1;
 
 	inode = ramfs_get_inode(sb, NULL, S_IFDIR | fsi->mount_opts.mode, 0);

ipc/mqueue.c

@@ -411,6 +411,7 @@ static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_blocksize_bits = PAGE_SHIFT;
 	sb->s_magic = MQUEUE_MAGIC;
 	sb->s_op = &mqueue_super_ops;
+	sb->s_d_flags = DCACHE_DONTCACHE;
 
 	inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
 	if (IS_ERR(inode))