They aren't used (nor even really usable) outside of pipe.c anyway
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
        .fasync         = pipe_rdwr_fasync,
 };
 
-struct file_operations read_pipe_fops = {
+static struct file_operations read_pipe_fops = {
        .llseek         = no_llseek,
        .read           = pipe_read,
        .readv          = pipe_readv,
        .fasync         = pipe_read_fasync,
 };
 
-struct file_operations write_pipe_fops = {
+static struct file_operations write_pipe_fops = {
        .llseek         = no_llseek,
        .read           = bad_pipe_r,
        .write          = pipe_write,
        .fasync         = pipe_write_fasync,
 };
 
-struct file_operations rdwr_pipe_fops = {
+static struct file_operations rdwr_pipe_fops = {
        .llseek         = no_llseek,
        .read           = pipe_read,
        .readv          = pipe_readv,
 
 extern struct file_operations read_fifo_fops;
 extern struct file_operations write_fifo_fops;
 extern struct file_operations rdwr_fifo_fops;
-extern struct file_operations read_pipe_fops;
-extern struct file_operations write_pipe_fops;
-extern struct file_operations rdwr_pipe_fops;
 
 extern int fs_may_remount_ro(struct super_block *);