iscsi-target: Add iSCSI fabric support for target v4.1

The Linux-iSCSI.org target module is a full featured in-kernel
software implementation of iSCSI target mode (RFC-3720) for the
current WIP mainline target v4.1 infrastructure code for the v3.1
kernel.  More information can be found here:

http://linux-iscsi.org/wiki/ISCSI

This includes support for:

   * RFC-3720 defined request / response state machines and support for
     all defined iSCSI operation codes from Section 10.2.1.2 using libiscsi
     include/scsi/iscsi_proto.h PDU definitions
   * Target v4.1 compatible control plane using the generic layout in
     target_core_fabric_configfs.c and fabric dependent attributes
     within /sys/kernel/config/target/iscsi/ subdirectories.
   * Target v4.1 compatible iSCSI statistics based on RFC-4544 (iSCSI MIBS)
   * Support for IPv6 and IPv4 network portals in M:N mapping to TPGs
   * iSCSI Error Recovery Hierarchy support
   * Per iSCSI connection RX/TX thread pair scheduling affinity
   * crc32c + crc32c_intel SSEv4 instruction offload support using libcrypto
   * CHAP Authentication support using libcrypto
   * Conversion to use internal SGl allocation with iscsit_alloc_buffs() ->
     transport_generic_map_mem_to_cmd()

(nab: Fix iscsi_proto.h struct scsi_lun usage from linux-next in commit:
      iscsi: Use struct scsi_lun in iscsi structs instead of u8[8])
(nab: Fix 32-bit compile warnings)

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andy Grover <agrover@redhat.com>
Acked-by: Roland Dreier <roland@kernel.org>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>

1 files changed, 474 insertions, 0 deletions

diff --git a/drivers/target/iscsi/iscsi_target_erl2.c b/drivers/target/iscsi/iscsi_target_erl2.c
new file mode 100644
index 00000000000..91a4d170bda
--- /dev/null
+++ b/drivers/target/iscsi/iscsi_target_erl2.c
@@ -0,0 +1,474 @@
+/*******************************************************************************
+ * This file contains error recovery level two functions used by
+ * the iSCSI Target driver.
+ *
+ * \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
+ *
+ * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
+ *
+ * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ ******************************************************************************/
+
+#include <scsi/iscsi_proto.h>
+#include <target/target_core_base.h>
+#include <target/target_core_transport.h>
+
+#include "iscsi_target_core.h"
+#include "iscsi_target_datain_values.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"
+
+/*
+ *	FIXME: Does RData SNACK apply here as well?
+ */
+void iscsit_create_conn_recovery_datain_values(
+	struct iscsi_cmd *cmd,
+	u32 exp_data_sn)
+{
+	u32 data_sn = 0;
+	struct iscsi_conn *conn = cmd->conn;
+
+	cmd->next_burst_len = 0;
+	cmd->read_data_done = 0;
+
+	while (exp_data_sn > data_sn) {
+		if ((cmd->next_burst_len +
+		     conn->conn_ops->MaxRecvDataSegmentLength) <
+		     conn->sess->sess_ops->MaxBurstLength) {
+			cmd->read_data_done +=
+			       conn->conn_ops->MaxRecvDataSegmentLength;
+			cmd->next_burst_len +=
+			       conn->conn_ops->MaxRecvDataSegmentLength;
+		} else {
+			cmd->read_data_done +=
+				(conn->sess->sess_ops->MaxBurstLength -
+				cmd->next_burst_len);
+			cmd->next_burst_len = 0;
+		}
+		data_sn++;
+	}
+}
+
+void iscsit_create_conn_recovery_dataout_values(
+	struct iscsi_cmd *cmd)
+{
+	u32 write_data_done = 0;
+	struct iscsi_conn *conn = cmd->conn;
+
+	cmd->data_sn = 0;
+	cmd->next_burst_len = 0;
+
+	while (cmd->write_data_done > write_data_done) {
+		if ((write_data_done + conn->sess->sess_ops->MaxBurstLength) <=
+		     cmd->write_data_done)
+			write_data_done += conn->sess->sess_ops->MaxBurstLength;
+		else
+			break;
+	}
+
+	cmd->write_data_done = write_data_done;
+}
+
+static int iscsit_attach_active_connection_recovery_entry(
+	struct iscsi_session *sess,
+	struct iscsi_conn_recovery *cr)
+{
+	spin_lock(&sess->cr_a_lock);
+	list_add_tail(&cr->cr_list, &sess->cr_active_list);
+	spin_unlock(&sess->cr_a_lock);
+
+	return 0;
+}
+
+static int iscsit_attach_inactive_connection_recovery_entry(
+	struct iscsi_session *sess,
+	struct iscsi_conn_recovery *cr)
+{
+	spin_lock(&sess->cr_i_lock);
+	list_add_tail(&cr->cr_list, &sess->cr_inactive_list);
+
+	sess->conn_recovery_count++;
+	pr_debug("Incremented connection recovery count to %u for"
+		" SID: %u\n", sess->conn_recovery_count, sess->sid);
+	spin_unlock(&sess->cr_i_lock);
+
+	return 0;
+}
+
+struct iscsi_conn_recovery *iscsit_get_inactive_connection_recovery_entry(
+	struct iscsi_session *sess,
+	u16 cid)
+{
+	struct iscsi_conn_recovery *cr;
+
+	spin_lock(&sess->cr_i_lock);
+	list_for_each_entry(cr, &sess->cr_inactive_list, cr_list) {
+		if (cr->cid == cid) {
+			spin_unlock(&sess->cr_i_lock);
+			return cr;
+		}
+	}
+	spin_unlock(&sess->cr_i_lock);
+
+	return NULL;
+}
+
+void iscsit_free_connection_recovery_entires(struct iscsi_session *sess)
+{
+	struct iscsi_cmd *cmd, *cmd_tmp;
+	struct iscsi_conn_recovery *cr, *cr_tmp;
+
+	spin_lock(&sess->cr_a_lock);
+	list_for_each_entry_safe(cr, cr_tmp, &sess->cr_active_list, cr_list) {
+		list_del(&cr->cr_list);
+		spin_unlock(&sess->cr_a_lock);
+
+		spin_lock(&cr->conn_recovery_cmd_lock);
+		list_for_each_entry_safe(cmd, cmd_tmp,
+				&cr->conn_recovery_cmd_list, i_list) {
+
+			list_del(&cmd->i_list);
+			cmd->conn = NULL;
+			spin_unlock(&cr->conn_recovery_cmd_lock);
+			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD) ||
+			    !(cmd->se_cmd.transport_wait_for_tasks))
+				iscsit_release_cmd(cmd);
+			else
+				cmd->se_cmd.transport_wait_for_tasks(
+						&cmd->se_cmd, 1, 1);
+			spin_lock(&cr->conn_recovery_cmd_lock);
+		}
+		spin_unlock(&cr->conn_recovery_cmd_lock);
+		spin_lock(&sess->cr_a_lock);
+
+		kfree(cr);
+	}
+	spin_unlock(&sess->cr_a_lock);
+
+	spin_lock(&sess->cr_i_lock);
+	list_for_each_entry_safe(cr, cr_tmp, &sess->cr_inactive_list, cr_list) {
+		list_del(&cr->cr_list);
+		spin_unlock(&sess->cr_i_lock);
+
+		spin_lock(&cr->conn_recovery_cmd_lock);
+		list_for_each_entry_safe(cmd, cmd_tmp,
+				&cr->conn_recovery_cmd_list, i_list) {
+
+			list_del(&cmd->i_list);
+			cmd->conn = NULL;
+			spin_unlock(&cr->conn_recovery_cmd_lock);
+			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD) ||
+			    !(cmd->se_cmd.transport_wait_for_tasks))
+				iscsit_release_cmd(cmd);
+			else
+				cmd->se_cmd.transport_wait_for_tasks(
+						&cmd->se_cmd, 1, 1);
+			spin_lock(&cr->conn_recovery_cmd_lock);
+		}
+		spin_unlock(&cr->conn_recovery_cmd_lock);
+		spin_lock(&sess->cr_i_lock);
+
+		kfree(cr);
+	}
+	spin_unlock(&sess->cr_i_lock);
+}
+
+int iscsit_remove_active_connection_recovery_entry(
+	struct iscsi_conn_recovery *cr,
+	struct iscsi_session *sess)
+{
+	spin_lock(&sess->cr_a_lock);
+	list_del(&cr->cr_list);
+
+	sess->conn_recovery_count--;
+	pr_debug("Decremented connection recovery count to %u for"
+		" SID: %u\n", sess->conn_recovery_count, sess->sid);
+	spin_unlock(&sess->cr_a_lock);
+
+	kfree(cr);
+
+	return 0;
+}
+
+int iscsit_remove_inactive_connection_recovery_entry(
+	struct iscsi_conn_recovery *cr,
+	struct iscsi_session *sess)
+{
+	spin_lock(&sess->cr_i_lock);
+	list_del(&cr->cr_list);
+	spin_unlock(&sess->cr_i_lock);
+
+	return 0;
+}
+
+/*
+ *	Called with cr->conn_recovery_cmd_lock help.
+ */
+int iscsit_remove_cmd_from_connection_recovery(
+	struct iscsi_cmd *cmd,
+	struct iscsi_session *sess)
+{
+	struct iscsi_conn_recovery *cr;
+
+	if (!cmd->cr) {
+		pr_err("struct iscsi_conn_recovery pointer for ITT: 0x%08x"
+			" is NULL!\n", cmd->init_task_tag);
+		BUG();
+	}
+	cr = cmd->cr;
+
+	list_del(&cmd->i_list);
+	return --cr->cmd_count;
+}
+
+void iscsit_discard_cr_cmds_by_expstatsn(
+	struct iscsi_conn_recovery *cr,
+	u32 exp_statsn)
+{
+	u32 dropped_count = 0;
+	struct iscsi_cmd *cmd, *cmd_tmp;
+	struct iscsi_session *sess = cr->sess;
+
+	spin_lock(&cr->conn_recovery_cmd_lock);
+	list_for_each_entry_safe(cmd, cmd_tmp,
+			&cr->conn_recovery_cmd_list, i_list) {
+
+		if (((cmd->deferred_i_state != ISTATE_SENT_STATUS) &&
+		     (cmd->deferred_i_state != ISTATE_REMOVE)) ||
+		     (cmd->stat_sn >= exp_statsn)) {
+			continue;
+		}
+
+		dropped_count++;
+		pr_debug("Dropping Acknowledged ITT: 0x%08x, StatSN:"
+			" 0x%08x, CID: %hu.\n", cmd->init_task_tag,
+				cmd->stat_sn, cr->cid);
+
+		iscsit_remove_cmd_from_connection_recovery(cmd, sess);
+
+		spin_unlock(&cr->conn_recovery_cmd_lock);
+		if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD) ||
+		    !(cmd->se_cmd.transport_wait_for_tasks))
+			iscsit_release_cmd(cmd);
+		else
+			cmd->se_cmd.transport_wait_for_tasks(
+					&cmd->se_cmd, 1, 0);
+		spin_lock(&cr->conn_recovery_cmd_lock);
+	}
+	spin_unlock(&cr->conn_recovery_cmd_lock);
+
+	pr_debug("Dropped %u total acknowledged commands on"
+		" CID: %hu less than old ExpStatSN: 0x%08x\n",
+			dropped_count, cr->cid, exp_statsn);
+
+	if (!cr->cmd_count) {
+		pr_debug("No commands to be reassigned for failed"
+			" connection CID: %hu on SID: %u\n",
+			cr->cid, sess->sid);
+		iscsit_remove_inactive_connection_recovery_entry(cr, sess);
+		iscsit_attach_active_connection_recovery_entry(sess, cr);
+		pr_debug("iSCSI connection recovery successful for CID:"
+			" %hu on SID: %u\n", cr->cid, sess->sid);
+		iscsit_remove_active_connection_recovery_entry(cr, sess);
+	} else {
+		iscsit_remove_inactive_connection_recovery_entry(cr, sess);
+		iscsit_attach_active_connection_recovery_entry(sess, cr);
+	}
+}
+
+int iscsit_discard_unacknowledged_ooo_cmdsns_for_conn(struct iscsi_conn *conn)
+{
+	u32 dropped_count = 0;
+	struct iscsi_cmd *cmd, *cmd_tmp;
+	struct iscsi_ooo_cmdsn *ooo_cmdsn, *ooo_cmdsn_tmp;
+	struct iscsi_session *sess = conn->sess;
+
+	mutex_lock(&sess->cmdsn_mutex);
+	list_for_each_entry_safe(ooo_cmdsn, ooo_cmdsn_tmp,
+			&sess->sess_ooo_cmdsn_list, ooo_list) {
+
+		if (ooo_cmdsn->cid != conn->cid)
+			continue;
+
+		dropped_count++;
+		pr_debug("Dropping unacknowledged CmdSN:"
+		" 0x%08x during connection recovery on CID: %hu\n",
+			ooo_cmdsn->cmdsn, conn->cid);
+		iscsit_remove_ooo_cmdsn(sess, ooo_cmdsn);
+	}
+	mutex_unlock(&sess->cmdsn_mutex);
+
+	spin_lock_bh(&conn->cmd_lock);
+	list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_list) {
+		if (!(cmd->cmd_flags & ICF_OOO_CMDSN))
+			continue;
+
+		list_del(&cmd->i_list);
+
+		spin_unlock_bh(&conn->cmd_lock);
+		if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD) ||
+		    !(cmd->se_cmd.transport_wait_for_tasks))
+			iscsit_release_cmd(cmd);
+		else
+			cmd->se_cmd.transport_wait_for_tasks(
+					&cmd->se_cmd, 1, 1);
+		spin_lock_bh(&conn->cmd_lock);
+	}
+	spin_unlock_bh(&conn->cmd_lock);
+
+	pr_debug("Dropped %u total unacknowledged commands on CID:"
+		" %hu for ExpCmdSN: 0x%08x.\n", dropped_count, conn->cid,
+				sess->exp_cmd_sn);
+	return 0;
+}
+
+int iscsit_prepare_cmds_for_realligance(struct iscsi_conn *conn)
+{
+	u32 cmd_count = 0;
+	struct iscsi_cmd *cmd, *cmd_tmp;
+	struct iscsi_conn_recovery *cr;
+
+	/*
+	 * Allocate an struct iscsi_conn_recovery for this connection.
+	 * Each struct iscsi_cmd contains an struct iscsi_conn_recovery pointer
+	 * (struct iscsi_cmd->cr) so we need to allocate this before preparing the
+	 * connection's command list for connection recovery.
+	 */
+	cr = kzalloc(sizeof(struct iscsi_conn_recovery), GFP_KERNEL);
+	if (!cr) {
+		pr_err("Unable to allocate memory for"
+			" struct iscsi_conn_recovery.\n");
+		return -1;
+	}
+	INIT_LIST_HEAD(&cr->cr_list);
+	INIT_LIST_HEAD(&cr->conn_recovery_cmd_list);
+	spin_lock_init(&cr->conn_recovery_cmd_lock);
+	/*
+	 * Only perform connection recovery on ISCSI_OP_SCSI_CMD or
+	 * ISCSI_OP_NOOP_OUT opcodes.  For all other opcodes call
+	 * list_del(&cmd->i_list); to release the command to the
+	 * session pool and remove it from the connection's list.
+	 *
+	 * Also stop the DataOUT timer, which will be restarted after
+	 * sending the TMR response.
+	 */
+	spin_lock_bh(&conn->cmd_lock);
+	list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_list) {
+
+		if ((cmd->iscsi_opcode != ISCSI_OP_SCSI_CMD) &&
+		    (cmd->iscsi_opcode != ISCSI_OP_NOOP_OUT)) {
+			pr_debug("Not performing realligence on"
+				" Opcode: 0x%02x, ITT: 0x%08x, CmdSN: 0x%08x,"
+				" CID: %hu\n", cmd->iscsi_opcode,
+				cmd->init_task_tag, cmd->cmd_sn, conn->cid);
+
+			list_del(&cmd->i_list);
+			spin_unlock_bh(&conn->cmd_lock);
+
+			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD) ||
+			    !(cmd->se_cmd.transport_wait_for_tasks))
+				iscsit_release_cmd(cmd);
+			else
+				cmd->se_cmd.transport_wait_for_tasks(
+						&cmd->se_cmd, 1, 0);
+			spin_lock_bh(&conn->cmd_lock);
+			continue;
+		}
+
+		/*
+		 * Special case where commands greater than or equal to
+		 * the session's ExpCmdSN are attached to the connection
+		 * list but not to the out of order CmdSN list.  The one
+		 * obvious case is when a command with immediate data
+		 * attached must only check the CmdSN against ExpCmdSN
+		 * after the data is received.  The special case below
+		 * is when the connection fails before data is received,
+		 * but also may apply to other PDUs, so it has been
+		 * made generic here.
+		 */
+		if (!(cmd->cmd_flags & ICF_OOO_CMDSN) && !cmd->immediate_cmd &&
+		     (cmd->cmd_sn >= conn->sess->exp_cmd_sn)) {
+			list_del(&cmd->i_list);
+			spin_unlock_bh(&conn->cmd_lock);
+
+			if (!(cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD) ||
+			    !(cmd->se_cmd.transport_wait_for_tasks))
+				iscsit_release_cmd(cmd);
+			else
+				cmd->se_cmd.transport_wait_for_tasks(
+						&cmd->se_cmd, 1, 1);
+			spin_lock_bh(&conn->cmd_lock);
+			continue;
+		}
+
+		cmd_count++;
+		pr_debug("Preparing Opcode: 0x%02x, ITT: 0x%08x,"
+			" CmdSN: 0x%08x, StatSN: 0x%08x, CID: %hu for"
+			" realligence.\n", cmd->iscsi_opcode,
+			cmd->init_task_tag, cmd->cmd_sn, cmd->stat_sn,
+			conn->cid);
+
+		cmd->deferred_i_state = cmd->i_state;
+		cmd->i_state = ISTATE_IN_CONNECTION_RECOVERY;
+
+		if (cmd->data_direction == DMA_TO_DEVICE)
+			iscsit_stop_dataout_timer(cmd);
+
+		cmd->sess = conn->sess;
+
+		list_del(&cmd->i_list);
+		spin_unlock_bh(&conn->cmd_lock);
+
+		iscsit_free_all_datain_reqs(cmd);
+
+		if ((cmd->se_cmd.se_cmd_flags & SCF_SE_LUN_CMD) &&
+		     cmd->se_cmd.transport_wait_for_tasks)
+			cmd->se_cmd.transport_wait_for_tasks(&cmd->se_cmd,
+					0, 0);
+		/*
+		 * Add the struct iscsi_cmd to the connection recovery cmd list
+		 */
+		spin_lock(&cr->conn_recovery_cmd_lock);
+		list_add_tail(&cmd->i_list, &cr->conn_recovery_cmd_list);
+		spin_unlock(&cr->conn_recovery_cmd_lock);
+
+		spin_lock_bh(&conn->cmd_lock);
+		cmd->cr = cr;
+		cmd->conn = NULL;
+	}
+	spin_unlock_bh(&conn->cmd_lock);
+	/*
+	 * Fill in the various values in the preallocated struct iscsi_conn_recovery.
+	 */
+	cr->cid = conn->cid;
+	cr->cmd_count = cmd_count;
+	cr->maxrecvdatasegmentlength = conn->conn_ops->MaxRecvDataSegmentLength;
+	cr->sess = conn->sess;
+
+	iscsit_attach_inactive_connection_recovery_entry(conn->sess, cr);
+
+	return 0;
+}
+
+int iscsit_connection_recovery_transport_reset(struct iscsi_conn *conn)
+{
+	atomic_set(&conn->connection_recovery, 1);
+
+	if (iscsit_close_connection(conn) < 0)
+		return -1;
+
+	return 0;
+}