Quelle  iscsi_target_erl2.c   Sprache: C

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

#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_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?
 */
static int iscsit_attach_active_connection_recovery_entry(
 struct iscsit_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 iscsit_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 iscsit_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_entries(struct iscsit_session *sess)
{
 struct iscsit_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_conn_node) {

   list_del_init(&cmd->i_conn_node);
   cmd->conn = NULL;
   spin_unlock(&cr->conn_recovery_cmd_lock);
   iscsit_free_cmd(cmd, true);
   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_conn_node) {

   list_del_init(&cmd->i_conn_node);
   cmd->conn = NULL;
   spin_unlock(&cr->conn_recovery_cmd_lock);
   iscsit_free_cmd(cmd, true);
   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 iscsit_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;
}

static void iscsit_remove_inactive_connection_recovery_entry(
 struct iscsi_conn_recovery *cr,
 struct iscsit_session *sess)
{
 spin_lock(&sess->cr_i_lock);
 list_del(&cr->cr_list);
 spin_unlock(&sess->cr_i_lock);
}

/*
 * Called with cr->conn_recovery_cmd_lock help.
 */
int iscsit_remove_cmd_from_connection_recovery(
 struct iscsit_cmd *cmd,
 struct iscsit_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_init(&cmd->i_conn_node);
 return --cr->cmd_count;
}

void iscsit_discard_cr_cmds_by_expstatsn(
 struct iscsi_conn_recovery *cr,
 u32 exp_statsn)
{
 u32 dropped_count = 0;
 struct iscsit_cmd *cmd, *cmd_tmp;
 struct iscsit_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_conn_node) {

  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);
  iscsit_free_cmd(cmd, true);
  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 iscsit_conn *conn)
{
 u32 dropped_count = 0;
 struct iscsit_cmd *cmd, *cmd_tmp;
 struct iscsi_ooo_cmdsn *ooo_cmdsn, *ooo_cmdsn_tmp;
 struct iscsit_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_conn_node) {
  if (!(cmd->cmd_flags & ICF_OOO_CMDSN))
   continue;

  list_del_init(&cmd->i_conn_node);

  spin_unlock_bh(&conn->cmd_lock);
  iscsit_free_cmd(cmd, true);
  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_reallegiance(struct iscsit_conn *conn)
{
 u32 cmd_count = 0;
 struct iscsit_cmd *cmd, *cmd_tmp;
 struct iscsi_conn_recovery *cr;

 /*
 * Allocate an struct iscsi_conn_recovery for this connection.
 * Each struct iscsit_cmd contains an struct iscsi_conn_recovery pointer
 * (struct iscsit_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_init(&cmd->i_conn_node); 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_conn_node) {

  if ((cmd->iscsi_opcode != ISCSI_OP_SCSI_CMD) &&
      (cmd->iscsi_opcode != ISCSI_OP_NOOP_OUT)) {
   pr_debug("Not performing reallegiance 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_init(&cmd->i_conn_node);
   spin_unlock_bh(&conn->cmd_lock);
   iscsit_free_cmd(cmd, true);
   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 &&
       iscsi_sna_gte(cmd->cmd_sn, conn->sess->exp_cmd_sn)) {
   list_del_init(&cmd->i_conn_node);
   spin_unlock_bh(&conn->cmd_lock);
   iscsit_free_cmd(cmd, true);
   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"
   " reallegiance.\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_init(&cmd->i_conn_node);
  spin_unlock_bh(&conn->cmd_lock);

  iscsit_free_all_datain_reqs(cmd);

  transport_wait_for_tasks(&cmd->se_cmd);
  /*
 * Add the struct iscsit_cmd to the connection recovery cmd list
 */
  spin_lock(&cr->conn_recovery_cmd_lock);
  list_add_tail(&cmd->i_conn_node, &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->maxxmitdatasegmentlength = conn->conn_ops->MaxXmitDataSegmentLength;
 cr->sess = conn->sess;

 iscsit_attach_inactive_connection_recovery_entry(conn->sess, cr);

 return 0;
}

int iscsit_connection_recovery_transport_reset(struct iscsit_conn *conn)
{
 atomic_set(&conn->connection_recovery, 1);

 if (iscsit_close_connection(conn) < 0)
  return -1;

 return 0;
}