NFSv4: Fix a sleep in atomic context in nfs4_callback_sequence()

 * a match.  If the slot is in use and the sequence numbers match, the

 * client is still waiting for a response to the original request.

 */

static bool referring_call_exists(struct nfs_client *clp,

static int referring_call_exists(struct nfs_client *clp,

				  uint32_t nrclists,

				  struct referring_call_list *rclists)

				  struct referring_call_list *rclists,

				  spinlock_t *lock)

	__releases(lock)

	__acquires(lock)

{

	bool status = false;

	int status = 0;

	int i, j;

	struct nfs4_session *session;

	struct nfs4_slot_table *tbl;

		for (j = 0; j < rclist->rcl_nrefcalls; j++) {

			ref = &rclist->rcl_refcalls[j];

			spin_unlock(lock);

			status = nfs4_slot_wait_on_seqid(tbl, ref->rc_slotid,

					ref->rc_sequenceid, HZ >> 1) < 0;

			spin_lock(lock);

			if (status)

				goto out;

		}

	 * related callback was received before the response to the original

	 * call.

	 */

	if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists)) {

	if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists,

				&tbl->slot_tbl_lock) < 0) {

		status = htonl(NFS4ERR_DELAY);

		goto out_unlock;

	}