this field is not used in any important way and probably should
have been removed by
Commit: 
8003d3c4aaa5 ("nfs4: treat lock owners as opaque values")
which removed the pid argument from nfs4_get_lock_state.
Except in unusual and uninteresting cases, two threads with the same
->tgid will have the same ->files pointer, so keeping them both
for comparison brings no benefit.
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
 
 {
        atomic_set(&l_ctx->count, 1);
        l_ctx->lockowner.l_owner = current->files;
-       l_ctx->lockowner.l_pid = current->tgid;
        INIT_LIST_HEAD(&l_ctx->list);
        atomic_set(&l_ctx->io_count, 0);
 }
        do {
                if (pos->lockowner.l_owner != current->files)
                        continue;
-               if (pos->lockowner.l_pid != current->tgid)
-                       continue;
                atomic_inc(&pos->count);
                return pos;
        } while ((pos = list_entry(pos->list.next, typeof(*pos), list)) != head);
 
        } else if (truncate && state != NULL) {
                struct nfs_lockowner lockowner = {
                        .l_owner = current->files,
-                       .l_pid = current->tgid,
                };
                if (!nfs4_valid_open_stateid(state))
                        return -EBADF;
 
 static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
                const struct nfs_lock_context *l2)
 {
-       return l1->lockowner.l_owner == l2->lockowner.l_owner
-               && l1->lockowner.l_pid == l2->lockowner.l_pid;
+       return l1->lockowner.l_owner == l2->lockowner.l_owner;
 }
 
 /**
 
                if (l_ctx && flctx &&
                    !(list_empty_careful(&flctx->flc_posix) &&
                      list_empty_careful(&flctx->flc_flock))) {
-                       do_flush |= l_ctx->lockowner.l_owner != current->files
-                               || l_ctx->lockowner.l_pid != current->tgid;
+                       do_flush |= l_ctx->lockowner.l_owner != current->files;
                }
                nfs_release_request(req);
                if (!do_flush)
 
 
 struct nfs_lockowner {
        fl_owner_t l_owner;
-       pid_t l_pid;
 };
 
 struct nfs_lock_context {