/*
* Generic SCSI-3 ALUA SCSI Device Handler
*
* Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH.
* All rights reserved.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <scsi/scsi.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dh.h>
#define ALUA_DH_NAME "alua"
#define ALUA_DH_VER "1.3"
#define TPGS_STATE_OPTIMIZED 0x0
#define TPGS_STATE_NONOPTIMIZED 0x1
#define TPGS_STATE_STANDBY 0x2
#define TPGS_STATE_UNAVAILABLE 0x3
#define TPGS_STATE_LBA_DEPENDENT 0x4
#define TPGS_STATE_OFFLINE 0xe
#define TPGS_STATE_TRANSITIONING 0xf
#define TPGS_SUPPORT_NONE 0x00
#define TPGS_SUPPORT_OPTIMIZED 0x01
#define TPGS_SUPPORT_NONOPTIMIZED 0x02
#define TPGS_SUPPORT_STANDBY 0x04
#define TPGS_SUPPORT_UNAVAILABLE 0x08
#define TPGS_SUPPORT_LBA_DEPENDENT 0x10
#define TPGS_SUPPORT_OFFLINE 0x40
#define TPGS_SUPPORT_TRANSITION 0x80
#define RTPG_FMT_MASK 0x70
#define RTPG_FMT_EXT_HDR 0x10
#define TPGS_MODE_UNINITIALIZED -1
#define TPGS_MODE_NONE 0x0
#define TPGS_MODE_IMPLICIT 0x1
#define TPGS_MODE_EXPLICIT 0x2
#define ALUA_INQUIRY_SIZE 36
#define ALUA_FAILOVER_TIMEOUT 60
#define ALUA_FAILOVER_RETRIES 5
/* flags passed from user level */
#define ALUA_OPTIMIZE_STPG 1
struct alua_dh_data {
int group_id;
int rel_port;
int tpgs;
int state;
int pref;
unsigned flags; /* used for optimizing STPG */
unsigned char inq[ALUA_INQUIRY_SIZE];
unsigned char *buff;
int bufflen;
unsigned char transition_tmo;
unsigned char sense[SCSI_SENSE_BUFFERSIZE];
int senselen;
struct scsi_device *sdev;
activate_complete callback_fn;
void *callback_data;
};
#define ALUA_POLICY_SWITCH_CURRENT 0
#define ALUA_POLICY_SWITCH_ALL 1
static char print_alua_state(int);
static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *);
static inline struct alua_dh_data *get_alua_data(struct scsi_device *sdev)
{
struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
BUG_ON(scsi_dh_data == NULL);
return ((struct alua_dh_data *) scsi_dh_data->buf);
}
static int realloc_buffer(struct alua_dh_data *h, unsigned len)
{
if (h->buff && h->buff != h->inq)
kfree(h->buff);
h->buff = kmalloc(len, GFP_NOIO);
if (!h->buff) {
h->buff = h->inq;
h->bufflen = ALUA_INQUIRY_SIZE;
return 1;
}
h->bufflen = len;
return 0;
}
static struct request *get_alua_req(struct scsi_device *sdev,
void *buffer, unsigned buflen, int rw)
{
struct request *rq;
struct request_queue *q = sdev->request_queue;
rq = blk_get_request(q, rw, GFP_NOIO);
if (!rq) {
sdev_printk(KERN_INFO, sdev,
"%s: blk_get_request failed\n", __func__);
return NULL;
}
if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) {
blk_put_request(rq);
sdev_printk(KERN_INFO, sdev,
"%s: blk_rq_map_kern failed\n", __func__);
return NULL;
}
rq->cmd_type = REQ_TYPE_BLOCK_PC;
rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
REQ_FAILFAST_DRIVER;
rq->retries = ALUA_FAILOVER_RETRIES;
rq->timeout = ALUA_FAILOVER_TIMEOUT * HZ;
return rq;
}
/*
* submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command
* @sdev: sdev the command should be sent to
*/
static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
{
struct request *rq;
int err = SCSI_DH_RES_TEMP_UNAVAIL;
rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
if (!rq)
goto done;
/* Prepare the command. */
rq->cmd[0] = INQUIRY;
rq->cmd[1] = 1;
rq->cmd[2] = 0x83;
rq->cmd[4] = h->bufflen;
rq->cmd_len = COMMAND_SIZE(INQUIRY);
rq->sense = h->sense;
memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
rq->sense_len = h->senselen = 0;
err = blk_execute_rq(rq->q, NULL, rq, 1);
if (err == -EIO) {
sdev_printk(KERN_INFO, sdev,
"%s: evpd inquiry failed with %x\n",
ALUA_DH_NAME, rq->errors);
h->senselen = rq->sense_len;
err = SCSI_DH_IO;
}
blk_put_request(rq);
done:
return err;
}
/*
* submit_rtpg - Issue a REPORT TARGET GROUP STATES command
* @sdev: sdev the command should be sent to
*/
static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h,
bool rtpg_ext_hdr_req)
{
struct request *rq;
int err = SCSI_DH_RES_TEMP_UNAVAIL;
rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
if (!rq)
goto done;
/* Prepare the command. */
rq->cmd[0] = MAINTENANCE_IN;
if (rtpg_ext_hdr_req)
rq->cmd[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
else
rq->cmd[1] = MI_REPORT_TARGET_PGS;
rq->cmd[6] = (h->bufflen >> 24) & 0xff;
rq->cmd[7] = (h->bufflen >> 16) & 0xff;
rq->cmd[8] = (h->bufflen >> 8) & 0xff;
rq->cmd[9] = h->bufflen & 0xff;
rq->cmd_len = COMMAND_SIZE(MAINTENANCE_IN);
rq->sense = h->sense;
memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
rq->sense_len = h->senselen = 0;
err = blk_execute_rq(rq->q, NULL, rq, 1);
if (err == -EIO) {
sdev_printk(KERN_INFO, sdev,
"%s: rtpg failed with %x\n",
ALUA_DH_NAME, rq->errors);
h->senselen = rq->sense_len;
err = SCSI_DH_IO;
}
blk_put_request(rq);
done:
return err;
}
/*
* alua_stpg - Evaluate SET TARGET GROUP STATES
* @sdev: the device to be evaluated
* @state: the new target group state
*
* Send a SET TARGET GROUP STATES command to the device.
* We only have to test here if we should resubmit the command;
* any other error is assumed as a failure.
*/
static void stpg_endio(struct request *req, int error)
{
struct alua_dh_data *h = req->end_io_data;
struct scsi_sense_hdr sense_hdr;
unsigned err = SCSI_DH_OK;
if (host_byte(req->errors) != DID_OK ||
msg_byte(req->errors) != COMMAND_COMPLETE) {
err = SCSI_DH_IO;
goto done;
}
if (req->sense_len > 0) {
err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
&sense_hdr);
if (!err) {
err = SCSI_DH_IO;
goto done;
}
err = alua_check_sense(h->sdev, &sense_hdr);
if (err == ADD_TO_MLQUEUE) {
err = SCSI_DH_RETRY;
goto done;
}
sdev_printk(KERN_INFO, h->sdev,
"%s: stpg sense code: %02x/%02x/%02x\n",
ALUA_DH_NAME, sense_hdr.sense_key,
sense_hdr.asc, sense_hdr.ascq);
err = SCSI_DH_IO;
} else if (error)
err = SCSI_DH_IO;
if (err == SCSI_DH_OK) {
h->state = TPGS_STATE_OPTIMIZED;
sdev_printk(KERN_INFO, h->sdev,
"%s: port group %02x switched to state %c\n",
ALUA_DH_NAME, h->group_id,
print_alua_state(h->state));
}
done:
req->end_io_data = NULL;
__blk_put_request(req->q, req);
if (h->callback_fn) {
h->callback_fn(h->callback_data, err);
h->callback_fn = h->callback_data = NULL;
}
return;
}
/*
* submit_stpg - Issue a SET TARGET GROUP STATES command
*
* Currently we're only setting the current target port group state
* to 'active/optimized' and let the array firmware figure out
* the states of the remaining groups.
*/
static unsigned submit_stpg(struct alua_dh_data *h)
{
struct request *rq;
int stpg_len = 8;
struct scsi_device *sdev = h->sdev;
/* Prepare the data buffer */
memset(h->buff, 0, stpg_len);
h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
h->buff[6] = (h->group_id >> 8) & 0xff;
h->buff[7] = h->group_id & 0xff;
rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
if (!rq)
return SCSI_DH_RES_TEMP_UNAVAIL;
/* Prepare the command. */
rq->cmd[0] = MAINTENANCE_OUT;
rq->cmd[1] = MO_SET_TARGET_PGS;
rq->cmd[6] = (stpg_len >> 24) & 0xff;
rq->cmd[7] = (stpg_len >> 16) & 0xff;
rq->cmd[8] = (stpg_len >> 8) & 0xff;
rq->cmd[9] = stpg_len & 0xff;
rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);
rq->sense = h->sense;
memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
rq->sense_len = h->senselen = 0;
rq->end_io_data = h;
blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
return SCSI_DH_OK;
}
/*
* alua_check_tpgs - Evaluate TPGS setting
* @sdev: device to be checked
*
* Examine the TPGS setting of the sdev to find out if ALUA
* is supported.
*/
static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
{
int err = SCSI_DH_OK;
h->tpgs = scsi_device_tpgs(sdev);
switch (h->tpgs) {
case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
sdev_printk(KERN_INFO, sdev,
"%s: supports implicit and explicit TPGS\n",
ALUA_DH_NAME);
break;
case TPGS_MODE_EXPLICIT:
sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
ALUA_DH_NAME);
break;
case TPGS_MODE_IMPLICIT:
sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
ALUA_DH_NAME);
break;
default:
h->tpgs = TPGS_MODE_NONE;
sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
ALUA_DH_NAME);
err = SCSI_DH_DEV_UNSUPP;
break;
}
return err;
}
/*
* alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83
* @sdev: device to be checked
*
* Extract the relative target port and the target port group
* descriptor from the list of identificators.
*/
static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
{
int len;
unsigned err;
unsigned char *d;
retry:
err = submit_vpd_inquiry(sdev, h);
if (err != SCSI_DH_OK)
return err;
/* Check if vpd page exceeds initial buffer */
len = (h->buff[2] << 8) + h->buff[3] + 4;
if (len > h->bufflen) {
/* Resubmit with the correct length */
if (realloc_buffer(h, len)) {
sdev_printk(KERN_WARNING, sdev,
"%s: kmalloc buffer failed\n",
ALUA_DH_NAME);
/* Temporary failure, bypass */
return SCSI_DH_DEV_TEMP_BUSY;
}
goto retry;
}
/*
* Now look for the correct descriptor.
*/
d = h->buff + 4;
while (d < h->buff + len) {
switch (d[1] & 0xf) {
case 0x4:
/* Relative target port */
h->rel_port = (d[6] << 8) + d[7];
break;
case 0x5:
/* Target port group */
h->group_id = (d[6] << 8) + d[7];
break;
default:
break;
}
d += d[3] + 4;
}
if (h->group_id == -1) {
/*
* Internal error; TPGS supported but required
* VPD identification descriptors not present.
* Disable ALUA support
*/
sdev_printk(KERN_INFO, sdev,
"%s: No target port descriptors found\n",
ALUA_DH_NAME);
h->state = TPGS_STATE_OPTIMIZED;
h->tpgs = TPGS_MODE_NONE;
err = SCSI_DH_DEV_UNSUPP;
} else {
sdev_printk(KERN_INFO, sdev,
"%s: port group %02x rel port %02x\n",
ALUA_DH_NAME, h->group_id, h->rel_port);
}
return err;
}
static char print_alua_state(int state)
{
switch (state) {
case TPGS_STATE_OPTIMIZED:
return 'A';
case TPGS_STATE_NONOPTIMIZED:
return 'N';
case TPGS_STATE_STANDBY:
return 'S';
case TPGS_STATE_UNAVAILABLE:
return 'U';
case TPGS_STATE_LBA_DEPENDENT:
return 'L';
case TPGS_STATE_OFFLINE:
return 'O';
case TPGS_STATE_TRANSITIONING:
return 'T';
default:
return 'X';
}
}
static int alua_check_sense(struct scsi_device *sdev,
struct scsi_sense_hdr *sense_hdr)
{
switch (sense_hdr->sense_key) {
case NOT_READY:
if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a)
/*
* LUN Not Accessible - ALUA state transition
*/
return ADD_TO_MLQUEUE;
if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b)
/*
* LUN Not Accessible -- Target port in standby state
*/
return SUCCESS;
if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c)
/*
* LUN Not Accessible -- Target port in unavailable state
*/
return SUCCESS;
if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12)
/*
* LUN Not Ready -- Offline
*/
return SUCCESS;
break;
case UNIT_ATTENTION:
if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
/*
* Power On, Reset, or Bus Device Reset, just retry.
*/
return ADD_TO_MLQUEUE;
if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
/*
* Mode Parameters Changed
*/
return ADD_TO_MLQUEUE;
if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06)
/*
* ALUA state changed
*/
return ADD_TO_MLQUEUE;
if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07)
/*
* Implicit ALUA state transition failed
*/
return ADD_TO_MLQUEUE;
if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03)
/*
* Inquiry data has changed
*/
return ADD_TO_MLQUEUE;
if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e)
/*
* REPORTED_LUNS_DATA_HAS_CHANGED is reported
* when switching controllers on targets like
* Intel Multi-Flex. We can just retry.
*/
return ADD_TO_MLQUEUE;
break;
}
return SCSI_RETURN_NOT_HANDLED;
}
/*
* alua_rtpg - Evaluate REPORT TARGET GROUP STATES
* @sdev: the device to be evaluated.
*
* Evaluate the Target Port Group State.
* Returns SCSI_DH_DEV_OFFLINED if the path is
* found to be unusable.
*/
static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
{
struct scsi_sense_hdr sense_hdr;
int len, k, off, valid_states = 0;
unsigned char *ucp;
unsigned err;
bool rtpg_ext_hdr_req = 1;
unsigned long expiry, interval = 0;
unsigned int tpg_desc_tbl_off;
unsigned char orig_transition_tmo;
if (!h->transition_tmo)
expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ);
else
expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ);
retry:
err = submit_rtpg(sdev, h, rtpg_ext_hdr_req);
if (err == SCSI_DH_IO && h->senselen > 0) {
err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
&sense_hdr);
if (!err)
return SCSI_DH_IO;
/*
* submit_rtpg() has failed on existing arrays
* when requesting extended header info, and
* the array doesn't support extended headers,
* even though it shouldn't according to T10.
* The retry without rtpg_ext_hdr_req set
* handles this.
*/
if (rtpg_ext_hdr_req == 1 &&
sense_hdr.sense_key == ILLEGAL_REQUEST &&
sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) {
rtpg_ext_hdr_req = 0;
goto retry;
}
err = alua_check_sense(sdev, &sense_hdr);
if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))
goto retry;
sdev_printk(KERN_INFO, sdev,
"%s: rtpg sense code %02x/%02x/%02x\n",
ALUA_DH_NAME, sense_hdr.sense_key,
sense_hdr.asc, sense_hdr.ascq);
err = SCSI_DH_IO;
}
if (err != SCSI_DH_OK)
return err;
len = (h->buff[0] << 24) + (h->buff[1] << 16) +
(h->buff[2] << 8) + h->buff[3] + 4;
if (len > h->bufflen) {
/* Resubmit with the correct length */
if (realloc_buffer(h, len)) {
sdev_printk(KERN_WARNING, sdev,
"%s: kmalloc buffer failed\n",__func__);
/* Temporary failure, bypass */
return SCSI_DH_DEV_TEMP_BUSY;
}
goto retry;
}
orig_transition_tmo = h->transition_tmo;
if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && h->buff[5] != 0)
h->transition_tmo = h->buff[5];
else
h->transition_tmo = ALUA_FAILOVER_TIMEOUT;
if (orig_transition_tmo != h->transition_tmo) {
sdev_printk(KERN_INFO, sdev,
"%s: transition timeout set to %d seconds\n",
ALUA_DH_NAME, h->transition_tmo);
expiry = jiffies + h->transition_tmo * HZ;
}
if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
tpg_desc_tbl_off = 8;
else
tpg_desc_tbl_off = 4;
for (k = tpg_desc_tbl_off, ucp = h->buff + tpg_desc_tbl_off;
k < len;
k += off, ucp += off) {
if (h->group_id == (ucp[2] << 8) + ucp[3]) {
h->state = ucp[0] & 0x0f;
h->pref = ucp[0] >> 7;
valid_states = ucp[1];
}
off = 8 + (ucp[7] * 4);
}
sdev_printk(KERN_INFO, sdev,
"%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
h->pref ? "preferred" : "non-preferred",
valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
switch (h->state) {
case TPGS_STATE_TRANSITIONING:
if (time_before(jiffies, expiry)) {
/* State transition, retry */
interval += 2000;
msleep(interval);
goto retry;
}
/* Transitioning time exceeded, set port to standby */
err = SCSI_DH_RETRY;
h->state = TPGS_STATE_STANDBY;
break;
case TPGS_STATE_OFFLINE:
/* Path unusable */
err = SCSI_DH_DEV_OFFLINED;
break;
default:
/* Useable path if active */
err = SCSI_DH_OK;
break;
}
return err;
}
/*
* alua_initialize - Initialize ALUA state
* @sdev: the device to be initialized
*
* For the prep_fn to work correctly we have
* to initialize the ALUA state for the device.
*/
static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
{
int err;
err = alua_check_tpgs(sdev, h);
if (err != SCSI_DH_OK)
goto out;
err = alua_vpd_inquiry(sdev, h);
if (err != SCSI_DH_OK)
goto out;
err = alua_rtpg(sdev, h);
if (err != SCSI_DH_OK)
goto out;
out:
return err;
}
/*
* alua_set_params - set/unset the optimize flag
* @sdev: device on the path to be activated
* params - parameters in the following format
* "no_of_params\0param1\0param2\0param3\0...\0"
* For example, to set the flag pass the following parameters
* from multipath.conf
* hardware_handler "2 alua 1"
*/
static int alua_set_params(struct scsi_device *sdev, const char *params)
{
struct alua_dh_data *h = get_alua_data(sdev);
unsigned int optimize = 0, argc;
const char *p = params;
int result = SCSI_DH_OK;
if ((sscanf(params, "%u", &argc) != 1) || (argc != 1))
return -EINVAL;
while (*p++)
;
if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1))
return -EINVAL;
if (optimize)
h->flags |= ALUA_OPTIMIZE_STPG;
else
h->flags &= ~ALUA_OPTIMIZE_STPG;
return result;
}
static uint optimize_stpg;
module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(optimize_stpg, "Allow use of a non-optimized path, rather than sending a STPG, when implicit TPGS is supported (0=No,1=Yes). Default is 0.");
/*
* alua_activate - activate a path
* @sdev: device on the path to be activated
*
* We're currently switching the port group to be activated only and
* let the array figure out the rest.
* There may be other arrays which require us to switch all port groups
* based on a certain policy. But until we actually encounter them it
* should be okay.
*/
static int alua_activate(struct scsi_device *sdev,
activate_complete fn, void *data)
{
struct alua_dh_data *h = get_alua_data(sdev);
int err = SCSI_DH_OK;
int stpg = 0;
err = alua_rtpg(sdev, h);
if (err != SCSI_DH_OK)
goto out;
if (optimize_stpg)
h->flags |= ALUA_OPTIMIZE_STPG;
if (h->tpgs & TPGS_MODE_EXPLICIT) {
switch (h->state) {
case TPGS_STATE_NONOPTIMIZED:
stpg = 1;
if ((h->flags & ALUA_OPTIMIZE_STPG) &&
(!h->pref) &&
(h->tpgs & TPGS_MODE_IMPLICIT))
stpg = 0;
break;
case TPGS_STATE_STANDBY:
case TPGS_STATE_UNAVAILABLE:
stpg = 1;
break;
case TPGS_STATE_OFFLINE:
err = SCSI_DH_IO;
break;
case TPGS_STATE_TRANSITIONING:
err = SCSI_DH_RETRY;
break;
default:
break;
}
}
if (stpg) {
h->callback_fn = fn;
h->callback_data = data;
err = submit_stpg(h);
if (err == SCSI_DH_OK)
return 0;
h->callback_fn = h->callback_data = NULL;
}
out:
if (fn)
fn(data, err);
return 0;
}
/*
* alua_prep_fn - request callback
*
* Fail I/O to all paths not in state
* active/optimized or active/non-optimized.
*/
static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
{
struct alua_dh_data *h = get_alua_data(sdev);
int ret = BLKPREP_OK;
if (h->state == TPGS_STATE_TRANSITIONING)
ret = BLKPREP_DEFER;
else if (h->state != TPGS_STATE_OPTIMIZED &&
h->state != TPGS_STATE_NONOPTIMIZED &&
h->state != TPGS_STATE_LBA_DEPENDENT) {
ret = BLKPREP_KILL;
req->cmd_flags |= REQ_QUIET;
}
return ret;
}
static bool alua_match(struct scsi_device *sdev)
{
return (scsi_device_tpgs(sdev) != 0);
}
static int alua_bus_attach(struct scsi_device *sdev);
static void alua_bus_detach(struct scsi_device *sdev);
static struct scsi_device_handler alua_dh = {
.name = ALUA_DH_NAME,
.module = THIS_MODULE,
.attach = alua_bus_attach,
.detach = alua_bus_detach,
.prep_fn = alua_prep_fn,
.check_sense = alua_check_sense,
.activate = alua_activate,
.set_params = alua_set_params,
.match = alua_match,
};
/*
* alua_bus_attach - Attach device handler
* @sdev: device to be attached to
*/
static int alua_bus_attach(struct scsi_device *sdev)
{
struct scsi_dh_data *scsi_dh_data;
struct alua_dh_data *h;
unsigned long flags;
int err = SCSI_DH_OK;
scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
+ sizeof(*h) , GFP_KERNEL);
if (!scsi_dh_data) {
sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
ALUA_DH_NAME);
return -ENOMEM;
}
scsi_dh_data->scsi_dh = &alua_dh;
h = (struct alua_dh_data *) scsi_dh_data->buf;
h->tpgs = TPGS_MODE_UNINITIALIZED;
h->state = TPGS_STATE_OPTIMIZED;
h->group_id = -1;
h->rel_port = -1;
h->buff = h->inq;
h->bufflen = ALUA_INQUIRY_SIZE;
h->sdev = sdev;
err = alua_initialize(sdev, h);
if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED))
goto failed;
if (!try_module_get(THIS_MODULE))
goto failed;
spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
sdev->scsi_dh_data = scsi_dh_data;
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
sdev_printk(KERN_NOTICE, sdev, "%s: Attached\n", ALUA_DH_NAME);
return 0;
failed:
kfree(scsi_dh_data);
sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME);
return -EINVAL;
}
/*
* alua_bus_detach - Detach device handler
* @sdev: device to be detached from
*/
static void alua_bus_detach(struct scsi_device *sdev)
{
struct scsi_dh_data *scsi_dh_data;
struct alua_dh_data *h;
unsigned long flags;
spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
scsi_dh_data = sdev->scsi_dh_data;
sdev->scsi_dh_data = NULL;
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
h = (struct alua_dh_data *) scsi_dh_data->buf;
if (h->buff && h->inq != h->buff)
kfree(h->buff);
kfree(scsi_dh_data);
module_put(THIS_MODULE);
sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);
}
static int __init alua_init(void)
{
int r;
r = scsi_register_device_handler(&alua_dh);
if (r != 0)
printk(KERN_ERR "%s: Failed to register scsi device handler",
ALUA_DH_NAME);
return r;
}
static void __exit alua_exit(void)
{
scsi_unregister_device_handler(&alua_dh);
}
module_init(alua_init);
module_exit(alua_exit);
MODULE_DESCRIPTION("DM Multipath ALUA support");
MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
MODULE_LICENSE("GPL");
MODULE_VERSION(ALUA_DH_VER);