path: root/drivers/target/iscsi/iscsi_target_erl1.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
 * This file contains error recovery level one used by the iSCSI Target driver.
 *
 * (c) Copyright 2007-2013 Datera, Inc.
 *
 * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 ******************************************************************************/

#include <linux/list.h>
#include <linux/slab.h>
#include <scsi/iscsi_proto.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/iscsi/iscsi_transport.h>

#include <target/iscsi/iscsi_target_core.h>
#include "iscsi_target_seq_pdu_list.h"
#include "iscsi_target_datain_values.h"
#include "iscsi_target_device.h"
#include "iscsi_target_tpg.h"
#include "iscsi_target_util.h"
#include "iscsi_target_erl0.h"
#include "iscsi_target_erl1.h"
#include "iscsi_target_erl2.h"
#include "iscsi_target.h"

#define OFFLOAD_BUF_SIZE	32768U

/*
 *	Used to dump excess datain payload for certain error recovery
 *	situations.  Receive in OFFLOAD_BUF_SIZE max of datain per rx_data().
 *
 *	dump_padding_digest denotes if padding and data digests need
 *	to be dumped.
 */
int iscsit_dump_data_payload(
	struct iscsit_conn *conn,
	u32 buf_len,
	int dump_padding_digest)
{
	char *buf;
	int ret = DATAOUT_WITHIN_COMMAND_RECOVERY, rx_got;
	u32 length, offset = 0, size;
	struct kvec iov;

	if (conn->sess->sess_ops->RDMAExtensions)
		return 0;

	if (dump_padding_digest) {
		buf_len = ALIGN(buf_len, 4);
		if (conn->conn_ops->DataDigest)
			buf_len += ISCSI_CRC_LEN;
	}

	length = min(buf_len, OFFLOAD_BUF_SIZE);

	buf = kzalloc(length, GFP_ATOMIC);
	if (!buf) {
		pr_err("Unable to allocate %u bytes for offload"
				" buffer.\n", length);
		return -1;
	}
	memset(&iov, 0, sizeof(struct kvec));

	while (offset < buf_len) {
		size = min(buf_len - offset, length);

		iov.iov_len = size;
		iov.iov_base = buf;

		rx_got = rx_data(conn, &iov, 1, size);
		if (rx_got != size) {
			ret = DATAOUT_CANNOT_RECOVER;
			break;
		}

		offset += size;
	}

	kfree(buf);
	return ret;
}

/*
 *	Used for retransmitting R2Ts from a R2T SNACK request.
 */
static int iscsit_send_recovery_r2t_for_snack(
	struct iscsit_cmd *cmd,
	struct iscsi_r2t *r2t)
{
	/*
	 * If the struct iscsi_r2t has not been sent yet, we can safely
	 * ignore retransmission
	 * of the R2TSN in question.
	 */
	spin_lock_bh(&cmd->r2t_lock);
	if (!r2t->sent_r2t) {
		spin_unlock_bh(&cmd->r2t_lock);
		return 0;
	}
	r2t->sent_r2t = 0;
	spin_unlock_bh(&cmd->r2t_lock);

	iscsit_add_cmd_to_immediate_queue(cmd, cmd->conn, ISTATE_SEND_R2T);

	return 0;
}

static int iscsit_handle_r2t_snack(
	struct iscsit_cmd *cmd,
	unsigned char *buf,
	u32 begrun,
	u32 runlength)
{
	u32 last_r2tsn;
	struct iscsi_r2t *r2t;

	/*
	 * Make sure the initiator is not requesting retransmission
	 * of R2TSNs already acknowledged by a TMR TASK_REASSIGN.
	 */
	if ((cmd->cmd_flags & ICF_GOT_DATACK_SNACK) &&
	    (begrun <= cmd->acked_data_sn)) {
		pr_err("ITT: 0x%08x, R2T SNACK requesting"
			" retransmission of R2TSN: 0x%08x to 0x%08x but already"
			" acked to  R2TSN: 0x%08x by TMR TASK_REASSIGN,"
			" protocol error.\n", cmd->init_task_tag, begrun,
			(begrun + runlength), cmd->acked_data_sn);

		return iscsit_reject_cmd(cmd, ISCSI_REASON_PROTOCOL_ERROR, buf);
	}

	if (runlength) {
		if ((begrun + runlength) > cmd<