diff options
Diffstat (limited to 'drivers/scsi/device_handler/scsi_dh_alua.c')
| -rw-r--r-- | drivers/scsi/device_handler/scsi_dh_alua.c | 802 |
1 files changed, 802 insertions, 0 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c new file mode 100644 index 00000000000..6e464488bca --- /dev/null +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -0,0 +1,802 @@ +/* + * Generic SCSI-3 ALUA SCSI Device Handler + * + * Copyright (C) 2007, 2008 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 <scsi/scsi.h> +#include <scsi/scsi_eh.h> +#include <scsi/scsi_dh.h> + +#define ALUA_DH_NAME "alua" +#define ALUA_DH_VER "1.2" + +#define TPGS_STATE_OPTIMIZED 0x0 +#define TPGS_STATE_NONOPTIMIZED 0x1 +#define TPGS_STATE_STANDBY 0x2 +#define TPGS_STATE_UNAVAILABLE 0x3 +#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_OFFLINE 0x40 +#define TPGS_SUPPORT_TRANSITION 0x80 + +#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 * HZ) +#define ALUA_FAILOVER_RETRIES 5 + +struct alua_dh_data { + int group_id; + int rel_port; + int tpgs; + int state; + unsigned char inq[ALUA_INQUIRY_SIZE]; + unsigned char *buff; + int bufflen; + unsigned char sense[SCSI_SENSE_BUFFERSIZE]; + int senselen; +}; + +#define ALUA_POLICY_SWITCH_CURRENT 0 +#define ALUA_POLICY_SWITCH_ALL 1 + +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", __FUNCTION__); + 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", __FUNCTION__); + return NULL; + } + + rq->cmd_type = REQ_TYPE_BLOCK_PC; + rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE; + rq->retries = ALUA_FAILOVER_RETRIES; + rq->timeout = ALUA_FAILOVER_TIMEOUT; + + return rq; +} + +/* + * submit_std_inquiry - Issue a standard INQUIRY command + * @sdev: sdev the command should be send to + */ +static int submit_std_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->inq, ALUA_INQUIRY_SIZE, READ); + if (!rq) + goto done; + + /* Prepare the command. */ + rq->cmd[0] = INQUIRY; + rq->cmd[1] = 0; + rq->cmd[2] = 0; + rq->cmd[4] = ALUA_INQUIRY_SIZE; + 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: std 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_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) +{ + 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; + 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; +} + +/* + * submit_stpg - Issue a SET TARGET GROUP STATES command + * @sdev: sdev the command should be sent to + * + * 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 scsi_device *sdev, struct alua_dh_data *h) +{ + struct request *rq; + int err = SCSI_DH_RES_TEMP_UNAVAIL; + int stpg_len = 8; + + /* Prepare the data buffer */ + memset(h->buff, 0, stpg_len); + h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f; + h->buff[6] = (h->group_id >> 8) & 0x0f; + h->buff[7] = h->group_id & 0x0f; + + rq = get_alua_req(sdev, h->buff, stpg_len, WRITE); + if (!rq) + goto done; + + /* 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; + + err = blk_execute_rq(rq->q, NULL, rq, 1); + if (err == -EIO) { + sdev_printk(KERN_INFO, sdev, + "%s: stpg 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_std_inquiry - Evaluate standard INQUIRY command + * @sdev: device to be checked + * + * Just extract the TPGS setting to find out if ALUA + * is supported. + */ +static int alua_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h) +{ + int err; + + err = submit_std_inquiry(sdev, h); + + if (err != SCSI_DH_OK) + return err; + + /* Check TPGS setting */ + h->tpgs = (h->inq[5] >> 4) & 0x3; + 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_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 NEEDS_RETRY; + 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 NEEDS_RETRY; + if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) { + /* + * ALUA state changed + */ + return NEEDS_RETRY; + } + if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) { + /* + * Implicit ALUA state transition failed + */ + return NEEDS_RETRY; + } + break; + } + + return SCSI_RETURN_NOT_HANDLED; +} + +/* + * 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 int alua_stpg(struct scsi_device *sdev, int state, + struct alua_dh_data *h) +{ + struct scsi_sense_hdr sense_hdr; + unsigned err; + int retry = ALUA_FAILOVER_RETRIES; + + retry: + err = submit_stpg(sdev, h); + 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; + err = alua_check_sense(sdev, &sense_hdr); + if (retry > 0 && err == NEEDS_RETRY) { + retry--; + goto retry; + } + sdev_printk(KERN_INFO, 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; + } + if (err == SCSI_DH_OK) { + h->state = state; + sdev_printk(KERN_INFO, sdev, + "%s: port group %02x switched to state %c\n", + ALUA_DH_NAME, h->group_id, + print_alua_state(h->state) ); + } + return err; +} + +/* + * 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 unuseable. + */ +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; + char *ucp; + unsigned err; + + retry: + err = submit_rtpg(sdev, h); + + 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; + + err = alua_check_sense(sdev, &sense_hdr); + if (err == NEEDS_RETRY) + 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",__FUNCTION__); + /* Temporary failure, bypass */ + return SCSI_DH_DEV_TEMP_BUSY; + } + goto retry; + } + + for (k = 4, ucp = h->buff + 4; k < len; k += off, ucp += off) { + if (h->group_id == (ucp[2] << 8) + ucp[3]) { + h->state = ucp[0] & 0x0f; + valid_states = ucp[1]; + } + off = 8 + (ucp[7] * 4); + } + + sdev_printk(KERN_INFO, sdev, + "%s: port group %02x state %c supports %c%c%c%c%c%c\n", + ALUA_DH_NAME, h->group_id, print_alua_state(h->state), + valid_states&TPGS_SUPPORT_TRANSITION?'T':'t', + valid_states&TPGS_SUPPORT_OFFLINE?'O':'o', + 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'); + + if (h->tpgs & TPGS_MODE_EXPLICIT) { + switch (h->state) { + case TPGS_STATE_TRANSITIONING: + /* State transition, retry */ + goto retry; + break; + case TPGS_STATE_OFFLINE: + /* Path is offline, fail */ + err = SCSI_DH_DEV_OFFLINED; + break; + default: + break; + } + } else { + /* Only Implicit ALUA support */ + if (h->state == TPGS_STATE_OPTIMIZED || + h->state == TPGS_STATE_NONOPTIMIZED || + h->state == TPGS_STATE_STANDBY) + /* Useable path if active */ + err = SCSI_DH_OK; + else + /* Path unuseable for unavailable/offline */ + err = SCSI_DH_DEV_OFFLINED; + } + 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_std_inquiry(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_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) +{ + struct alua_dh_data *h = get_alua_data(sdev); + int err = SCSI_DH_OK; + + if (h->group_id != -1) { + err = alua_rtpg(sdev, h); + if (err != SCSI_DH_OK) + goto out; + } + + if (h->tpgs == TPGS_MODE_EXPLICIT && h->state != TPGS_STATE_OPTIMIZED) + err = alua_stpg(sdev, TPGS_STATE_OPTIMIZED, h); + +out: + return err; +} + +/* + * 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_OPTIMIZED && + h->state != TPGS_STATE_NONOPTIMIZED) { + ret = BLKPREP_KILL; + req->cmd_flags |= REQ_QUIET; + } + return ret; + +} + +const struct scsi_dh_devlist alua_dev_list[] = { + {"HP", "MSA VOLUME" }, + {"HP", "HSV101" }, + {"HP", "HSV111" }, + {"HP", "HSV200" }, + {"HP", "HSV210" }, + {"HP", "HSV300" }, + {"IBM", "2107900" }, + {"IBM", "2145" }, + {"Pillar", "Axiom" }, + {NULL, NULL} +}; + +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, + .devlist = alua_dev_list, + .attach = alua_bus_attach, + .detach = alua_bus_detach, + .prep_fn = alua_prep_fn, + .check_sense = alua_check_sense, + .activate = alua_activate, +}; + +/* + * 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(struct scsi_device_handler *) + + 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; + + err = alua_initialize(sdev, h); + if (err != SCSI_DH_OK) + 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); + + 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); |