NFS: remove l_pid field from nfs_lockowner

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 <[e-mail]>
Signed-off-by: NeilBrown <[e-mail]>
Reviewed-by: Jeff Layton <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/inode.c

···
 {
 	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;

fs/nfs/nfs4proc.c

···
 	} 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;

fs/nfs/pagelist.c

···
 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;
 }
 
 /**

fs/nfs/write.c

···
 		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)

include/linux/nfs_fs.h

···
 
 struct nfs_lockowner {
 	fl_owner_t l_owner;
-	pid_t l_pid;
 };
 
 struct nfs_lock_context {