path: root/drivers/s390/scsi/zfcp_erp.c

/*
 * zfcp device driver
 *
 * Error Recovery Procedures (ERP).
 *
 * Copyright IBM Corp. 2002, 2015
 */

#define KMSG_COMPONENT "zfcp"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/kthread.h>
#include "zfcp_ext.h"
#include "zfcp_reqlist.h"

#define ZFCP_MAX_ERPS                   3

enum zfcp_erp_act_flags {
	ZFCP_STATUS_ERP_TIMEDOUT	= 0x10000000,
	ZFCP_STATUS_ERP_CLOSE_ONLY	= 0x01000000,
	ZFCP_STATUS_ERP_DISMISSING	= 0x00100000,
	ZFCP_STATUS_ERP_DISMISSED	= 0x00200000,
	ZFCP_STATUS_ERP_LOWMEM		= 0x00400000,
	ZFCP_STATUS_ERP_NO_REF		= 0x00800000,
};

enum zfcp_erp_steps {
	ZFCP_ERP_STEP_UNINITIALIZED	= 0x0000,
	ZFCP_ERP_STEP_FSF_XCONFIG	= 0x0001,
	ZFCP_ERP_STEP_PHYS_PORT_CLOSING	= 0x0010,
	ZFCP_ERP_STEP_PORT_CLOSING	= 0x0100,
	ZFCP_ERP_STEP_PORT_OPENING	= 0x0800,
	ZFCP_ERP_STEP_LUN_CLOSING	= 0x1000,
	ZFCP_ERP_STEP_LUN_OPENING	= 0x2000,
};

enum zfcp_erp_act_type {
	ZFCP_ERP_ACTION_REOPEN_LUN         = 1,
	ZFCP_ERP_ACTION_REOPEN_PORT	   = 2,
	ZFCP_ERP_ACTION_REOPEN_PORT_FORCED = 3,
	ZFCP_ERP_ACTION_REOPEN_ADAPTER     = 4,
};

enum zfcp_erp_act_state {
	ZFCP_ERP_ACTION_RUNNING = 1,
	ZFCP_ERP_ACTION_READY   = 2,
};

enum zfcp_erp_act_result {
	ZFCP_ERP_SUCCEEDED = 0,
	ZFCP_ERP_FAILED    = 1,
	ZFCP_ERP_CONTINUES = 2,
	ZFCP_ERP_EXIT      = 3,
	ZFCP_ERP_DISMISSED = 4,
	ZFCP_ERP_NOMEM     = 5,
};

static void zfcp_erp_adapter_block(struct zfcp_adapter *adapter, int mask)
{
	zfcp_erp_clear_adapter_status(adapter,
				       ZFCP_STATUS_COMMON_UNBLOCKED | mask);
}

static int zfcp_erp_action_exists(struct zfcp_erp_action *act)
{
	struct zfcp_erp_action *curr_act;

	list_for_each_entry(curr_act, &act->adapter->erp_running_head, list)
		if (act == curr_act)
			return ZFCP_ERP_ACTION_RUNNING;
	return 0;
}

static void zfcp_erp_action_ready(struct zfcp_erp_action *act)
{
	struct zfcp_adapter *adapter = act->adapter;

	list_move(&act->list, &act->adapter->erp_ready_head);
	zfcp_dbf_rec_run("erardy1", act);
	wake_up(&adapter->erp_ready_wq);
	zfcp_dbf_rec_run("erardy2", act);
}

static void zfcp_erp_action_dismiss(struct zfcp_erp_action *act)
{
	act->status |= ZFCP_STATUS_ERP_DISMISSED;
	if (zfcp_erp_action_exists(act) == ZFCP_ERP_ACTION_RUNNING)
		zfcp_erp_action_ready(act);
}

static void zfcp_erp_action_dismiss_lun(struct scsi_device *sdev)
{
	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);

	if (atomic_read(&zfcp_sdev->status) & ZFCP_STATUS_COMMON_ERP_INUSE)
		zfcp_erp_action_dismiss(&zfcp_sdev->erp_action);
}

static void zfcp_erp_action_dismiss_port(struct zfcp_port *port)
{
	struct scsi_device *sdev;

	if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_ERP_INUSE)
		zfcp_erp_action_dismiss(&port->erp_action);
	else {
		spin_lock(port->adapter->scsi_host->host_lock);
		__shost_for_each_device(sdev, port->adapter->scsi_host)
			if (sdev_to_zfcp(sdev)->port == port)
				zfcp_erp_action_dismiss_lun(sdev);
		spin_unlock(port->adapter->scsi_host->host_lock);
	}
}

static void zfcp_erp_action_dismiss_adapter(struct zfcp_adapter *adapter)
{
	struct zfcp_port *port;

	if (atomic_read(&adapter->status) & ZFCP_STATUS_COMMON_ERP_INUSE)
		zfcp_erp_action_dismiss(&adapter->erp_action);
	else {
		read_lock(&adapter->port_list_lock);
		list_for_each_entry(port, &adapter->port_list, list)
		    zfcp_erp_action_dismiss_port(port);
		read_unlock(&adapter->port_list_lock);
	}
}

static int zfcp_erp_required_act(int want, struct zfcp_adapter *adapter,
				 struct zfcp_port *port,
				 struct scsi_device *sdev)
{
	int need = want;
	int l_status, p_status, a_status;
	struct zfcp_scsi_dev *zfcp_sdev;

	switch (want) {
	case ZFCP_ERP_ACTION_REOPEN_LUN:
		zfcp_sdev = sdev_to_zfcp(sdev);
		l_status = atomic_read(&zfcp_sdev->status);
		if (l_status & ZFCP_STATUS_COMMON_ERP_INUSE)
			return 0;
		p_status = atomic_read(&port->status);
		if (!(p_status & ZFCP_STATUS_COMMON_RUNNING) ||
		      p_status & ZFCP_STATUS_COMMON_ERP_FAILED)
			return 0;
		if (!(p_status & ZFCP_STATUS_COMMON_UNBLOCKED))
			need = ZFCP_ERP_ACTION_REOPEN_PORT;
		/* fall through */
	case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
		p_status = atomic_read(&port->status);
		if (!(p_status & ZFCP_STATUS_COMMON_OPEN))
			need = ZFCP_ERP_ACTION_REOPEN_PORT;
		/* fall through */
	case ZFCP_ERP_ACTION_REOPEN_PORT:
		p_status = atomic_read(&port->status);
		if (p_status & ZFCP_STATUS_COMMON_ERP_INUSE)
			return 0;
		a_status = atomic_read(&adapter->status);
		if (!(a_status & ZFCP_STATUS_COMMON_RUNNING) ||
		      a_status & ZFCP_STATUS_COMMON_ERP_FAILED)
			return 0;
		if (p_status & ZFCP_STATUS_COMMON_NOESC)
			return need;
		if (!(a_status & ZFCP_STATUS_COMMON_UNBLOCKED))
			need = ZFCP_ERP_ACTION_REOPEN_ADAPTER;
		/* fall through */
	case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
		a_status = atomic_read(&adapter->status);
		if (a_status & ZFCP_STATUS_COMMON_ERP_INUSE)
			return 0;
		if (!(a_status & ZFCP_STATUS_COMMON_RUNNING) &&
		    !(a_status & ZFCP_STATUS_COMMON_OPEN))
			return 0; /* shutdown requested for closed adapter */
	}

	return need;
}

static struct zfcp_erp_action *zfcp_erp_setup_act(int need, u32 act_status,
						  struct zfcp_adapter *adapter,
						  struct zfcp_port *port,
						  struct scsi_device *sdev)
{
	struct zfcp_erp_action *erp_action;
	struct zfcp_scsi_dev *zfcp_sdev;

	switch (need) {
	case ZFCP_ERP_ACTION_REOPEN_LUN:
		zfcp_sdev = sdev_to_zfcp(sdev);
		if (!(act_status & ZFCP_STATUS_ERP_NO_REF))
			if (scsi_device_get(sdev))
				return NULL;
		atomic_or(ZFCP_STATUS_COMMON_ERP_INUSE,
				&zfcp_sdev->status);
		erp_action = &zfcp_sdev->erp_action;
		memset(erp_action, 0, sizeof(struct zfcp_erp_action));
		erp_action->port = port;
		erp_action->sdev = sdev;
		if (!(atomic_read(&