Commit 555a65f6 authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

iser-target: Fix queue-full response handling 



This patch addresses two queue-full handling bugs in iser-target.

The first is propagating isert_rdma_rw_ctx_post() return back
to target-core via isert_put_datain() + isert_get_dataout()
callbacks, in order to trigger queue-full logic in target-core.
Note target-core expects -EAGAIN or -ENOMEM error to signal
RDMA WRITE/READ data-transfer callbacks should be retried,
after queue-full logic been invoked.

Other types of errors propagated up from RDMA RW API will result
in target-core generating internal CHECK_CONDITION status,
avoiding subsequent isert_put_datain() and isert_get_dataout()
iscsit_transport callback retry attempts.

The second is to use transport_generic_request_failure()
during T10-PI hw-offload errors in isert_rdma_write_done()
and isert_rdma_read_done(), so CHECK_CONDITION queue-full
is handled internally by target-core.

Also add isert_put_response() T10-PI failure case fixme in
isert_rdma_write_done(), which is currently not internally
retried or released until session reinstatement.

Reported-by: default avatarPotnuri Bharat Teja <bharat@chelsio.com>
Reviewed-by: default avatarPotnuri Bharat Teja <bharat@chelsio.com>
Tested-by: default avatarPotnuri Bharat Teja <bharat@chelsio.com>
Cc: Potnuri Bharat Teja <bharat@chelsio.com>
Reported-by: default avatarSteve Wise <swise@opengridcomputing.com>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent a4467018

drivers/infiniband/ulp/isert/ib_isert.c

+35 −18
Original line number Diff line number Diff line
@@ -1659,10 +1659,23 @@ isert_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc) 
	ret = isert_check_pi_status(cmd, isert_cmd->rw.sig->sig_mr);

	isert_rdma_rw_ctx_destroy(isert_cmd, isert_conn);



	if (ret) {

		/*

		 * transport_generic_request_failure() expects to have

		 * plus two references to handle queue-full, so re-add

		 * one here as target-core will have already dropped

		 * it after the first isert_put_datain() callback.

		 */

		kref_get(&cmd->cmd_kref);

		transport_generic_request_failure(cmd, cmd->pi_err);

	} else {

		/*

		 * XXX: isert_put_response() failure is not retried.

		 */

		ret = isert_put_response(isert_conn->conn, isert_cmd->iscsi_cmd);

		if (ret)

		transport_send_check_condition_and_sense(cmd, cmd->pi_err, 0);

	else

		isert_put_response(isert_conn->conn, isert_cmd->iscsi_cmd);

			pr_warn_ratelimited("isert_put_response() ret: %d\n", ret);

	}

}



static void
@@ -1699,14 +1712,16 @@ isert_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc) 
	cmd->i_state = ISTATE_RECEIVED_LAST_DATAOUT;

	spin_unlock_bh(&cmd->istate_lock);



	if (ret) {

		target_put_sess_cmd(se_cmd);

		transport_send_check_condition_and_sense(se_cmd,

							 se_cmd->pi_err, 0);

	} else {

	/*

	 * transport_generic_request_failure() will drop the extra

	 * se_cmd->cmd_kref reference after T10-PI error, and handle

	 * any non-zero ->queue_status() callback error retries.

	 */

	if (ret)

		transport_generic_request_failure(se_cmd, se_cmd->pi_err);

	else

		target_execute_cmd(se_cmd);

}

}



static void

isert_do_control_comp(struct work_struct *work)
@@ -2171,26 +2186,28 @@ isert_put_datain(struct iscsi_conn *conn, struct iscsi_cmd *cmd) 
		chain_wr = &isert_cmd->tx_desc.send_wr;

	}



	isert_rdma_rw_ctx_post(isert_cmd, isert_conn, cqe, chain_wr);

	isert_dbg("Cmd: %p posted RDMA_WRITE for iSER Data READ\n", isert_cmd);

	return 1;

	rc = isert_rdma_rw_ctx_post(isert_cmd, isert_conn, cqe, chain_wr);

	isert_dbg("Cmd: %p posted RDMA_WRITE for iSER Data READ rc: %d\n",

		  isert_cmd, rc);

	return rc;

}



static int

isert_get_dataout(struct iscsi_conn *conn, struct iscsi_cmd *cmd, bool recovery)

{

	struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);

	int ret;



	isert_dbg("Cmd: %p RDMA_READ data_length: %u write_data_done: %u\n",

		 isert_cmd, cmd->se_cmd.data_length, cmd->write_data_done);



	isert_cmd->tx_desc.tx_cqe.done = isert_rdma_read_done;

	isert_rdma_rw_ctx_post(isert_cmd, conn->context,

	ret = isert_rdma_rw_ctx_post(isert_cmd, conn->context,

				     &isert_cmd->tx_desc.tx_cqe, NULL);



	isert_dbg("Cmd: %p posted RDMA_READ memory for ISER Data WRITE\n",

		 isert_cmd);

	return 0;

	isert_dbg("Cmd: %p posted RDMA_READ memory for ISER Data WRITE rc: %d\n",

		 isert_cmd, ret);

	return ret;

}



static int

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