[dm-devel] [PATCH 2/3] multipath: Add new SPC-3 ALUA hardware handler
Hannes Reinecke
hare at suse.de
Thu Nov 15 09:16:34 UTC 2007
This adds a new SPC-3 ALUA hardware handler for multipathing.
Signed-off-by: Hannes Reinecke <hare at suse.de>
---
drivers/md/Kconfig | 7 +
drivers/md/Makefile | 2 +
drivers/md/dm-mpath-alua.c | 681 ++++++++++++++++++++++++++++++++++++++++++++
include/scsi/scsi.h | 3 +
4 files changed, 693 insertions(+), 0 deletions(-)
create mode 100644 drivers/md/dm-mpath-alua.c
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 9b6fbf0..2044fb4 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -273,6 +273,13 @@ config DM_MULTIPATH_HP
---help---
Multipath support for HP MSA (Active/Passive) series hardware.
+config DM_MULTIPATH_ALUA
+ tristate "SPC-3 ALUA multipath support (EXPERIMENTAL)"
+ depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
+ ---help---
+ Multipath support for SPC-3 Asymmetric Logical Unit
+ Access (ALUA).
+
config DM_DELAY
tristate "I/O delaying target (EXPERIMENTAL)"
depends on BLK_DEV_DM && EXPERIMENTAL
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index d9aa7ed..6b8fd78 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -8,6 +8,7 @@ dm-multipath-objs := dm-hw-handler.o dm-path-selector.o dm-mpath.o
dm-snapshot-objs := dm-snap.o dm-exception-store.o
dm-mirror-objs := dm-log.o dm-raid1.o
dm-rdac-objs := dm-mpath-rdac.o
+dm-alua-objs := dm-mpath-alua.o
dm-hp-sw-objs := dm-mpath-hp-sw.o
md-mod-objs := md.o bitmap.o
raid456-objs := raid5.o raid6algos.o raid6recov.o raid6tables.o \
@@ -38,6 +39,7 @@ obj-$(CONFIG_DM_MULTIPATH) += dm-multipath.o dm-round-robin.o
obj-$(CONFIG_DM_MULTIPATH_EMC) += dm-emc.o
obj-$(CONFIG_DM_MULTIPATH_HP) += dm-hp-sw.o
obj-$(CONFIG_DM_MULTIPATH_RDAC) += dm-rdac.o
+obj-$(CONFIG_DM_MULTIPATH_ALUA) += dm-alua.o
obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot.o
obj-$(CONFIG_DM_MIRROR) += dm-mirror.o
obj-$(CONFIG_DM_ZERO) += dm-zero.o
diff --git a/drivers/md/dm-mpath-alua.c b/drivers/md/dm-mpath-alua.c
new file mode 100644
index 0000000..cc954f2
--- /dev/null
+++ b/drivers/md/dm-mpath-alua.c
@@ -0,0 +1,681 @@
+/*
+ * Generic SCSI-3 ALUA DM HW handler
+ *
+ * Copyright (C) 2007 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_cmnd.h>
+#include <scsi/scsi_eh.h>
+
+#define DM_MSG_PREFIX "multipath alua"
+
+#include "dm.h"
+#include "dm-hw-handler.h"
+
+#define DM_ALUA_HWH_NAME "alua"
+#define DM_ALUA_HWH_VER "1.0"
+
+#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)
+
+struct alua_handler {
+ struct dm_path *path;
+ int group_id;
+ int rel_port;
+ int tpgs;
+ int state;
+ int retry;
+ unsigned char inq[ALUA_INQUIRY_SIZE];
+ unsigned char *buff;
+ int bufflen;
+ unsigned char sense[SCSI_SENSE_BUFFERSIZE];
+};
+
+#define ALUA_POLICY_SWITCH_CURRENT 0
+#define ALUA_POLICY_SWITCH_ALL 1
+
+static inline int had_failures(struct request *req, int error)
+{
+ return (error || host_byte(req->errors) != DID_OK ||
+ msg_byte(req->errors) != COMMAND_COMPLETE);
+}
+
+static int realloc_buffer(struct alua_handler *h, unsigned len)
+{
+ if (h->buff && h->buff != h->inq)
+ kfree(h->buff);
+
+ h->buff = kzalloc(len, GFP_KERNEL);
+ if (!h->buff) {
+ DMINFO("%s: kmalloc buffer failed",__FUNCTION__);
+ h->buff = h->inq;
+ h->bufflen = ALUA_INQUIRY_SIZE;
+ return 1;
+ }
+ h->bufflen = len;
+ return 0;
+}
+
+static struct request *prepare_req(struct hw_handler *hwh,
+ void *buffer, unsigned buflen, int rw)
+{
+ struct alua_handler *h = hwh->context;
+ struct request *rq;
+ struct request_queue *q = bdev_get_queue(h->path->dev->bdev);
+
+ if (!q) {
+ DMWARN("%s: no queue", __FUNCTION__);
+ return NULL;
+ }
+
+ rq = blk_get_request(q, rw, GFP_KERNEL);
+
+ if (!rq) {
+ DMINFO("%s: blk_get_request failed", __FUNCTION__);
+ return NULL;
+ }
+
+ if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_KERNEL)) {
+ blk_put_request(rq);
+ DMINFO("%s: blk_rq_map_kern failed", __FUNCTION__);
+ return NULL;
+ }
+
+ memset(&rq->cmd, 0, BLK_MAX_CDB);
+ rq->sense = h->sense;
+ memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
+ rq->sense_len = 0;
+
+ rq->timeout = ALUA_FAILOVER_TIMEOUT;
+ rq->cmd_type = REQ_TYPE_BLOCK_PC;
+ rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE | REQ_QUIET;
+ rq->end_io_data = hwh;
+
+ return rq;
+}
+
+/*
+ * Standard INQUIRY endio handler
+ *
+ * Just extract the TPGS setting to find out if ALUA
+ * is supported.
+ */
+static void std_inquiry_endio(struct request *req, int error)
+{
+ struct hw_handler *hwh = req->end_io_data;
+ struct alua_handler *h = hwh->context;
+
+ if (had_failures(req, error)) {
+ DMWARN("%s: std inquiry error %x %x",
+ h->path->dev->name, req->errors, error);
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ goto done;
+ }
+
+ /* Check TPGS setting */
+ h->tpgs = (h->inq[5] >> 4) & 0x3;
+ switch (h->tpgs) {
+ case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
+ DMWARN("%s: supports implicit and explicit TPGS",
+ h->path->dev->name);
+ break;
+ case TPGS_MODE_EXPLICIT:
+ DMWARN("%s: supports explicit TPGS",
+ h->path->dev->name);
+ break;
+ case TPGS_MODE_IMPLICIT:
+ DMWARN("%s: supports implicit TPGS",
+ h->path->dev->name);
+ break;
+ default:
+ DMWARN("%s: TPGS not supported (%x)",
+ h->path->dev->name, h->inq[5] >> 4);
+ h->tpgs = TPGS_MODE_NONE;
+ break;
+ }
+
+ if (h->tpgs == TPGS_MODE_NONE) {
+ /*
+ * ALUA not supported
+ */
+ dm_pg_init_complete(h->path, 0);
+ } else
+ dm_enqueue_hw_workq(hwh);
+
+ done:
+ __blk_put_request(req->q, req);
+}
+
+/*
+ * Issue a standard INQUIRY command
+ */
+static void submit_std_inquiry(struct hw_handler *hwh)
+{
+ struct alua_handler *h = hwh->context;
+ struct request *rq;
+
+ if (h->buff && h->buff != h->inq) {
+ DMWARN("%s: std inq free buf", h->path->dev->name);
+ kfree(h->buff);
+ }
+
+ h->buff = h->inq;
+ h->bufflen = ALUA_INQUIRY_SIZE;
+
+ rq = prepare_req(hwh, h->inq, ALUA_INQUIRY_SIZE, READ);
+ if (!rq) {
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ return;
+ }
+
+ /* Prepare the command. */
+ rq->cmd[0] = INQUIRY;
+ rq->cmd[1] = 0;
+ rq->cmd[2] = 0;
+ rq->cmd[3] = 0;
+ rq->cmd[4] = ALUA_INQUIRY_SIZE;
+ rq->cmd_len = COMMAND_SIZE(INQUIRY);
+
+ DMINFO("%s: submit std inq %x %x %x %x %x %x",
+ h->path->dev->name, rq->cmd[0], rq->cmd[1],
+ rq->cmd[2], rq->cmd[3], rq->cmd[4], rq->cmd[5]);
+
+ blk_execute_rq_nowait(rq->q, NULL, rq, 1, std_inquiry_endio);
+}
+
+/*
+ * INQUIRY vpd page 0x83 endio handler
+ *
+ * Extract the relative target port and the target port group
+ * descriptor from the list of identificators.
+ */
+static void vpd_inquiry_endio(struct request *req, int error)
+{
+ struct hw_handler *hwh = req->end_io_data;
+ struct alua_handler *h = hwh->context;
+ int len;
+ unsigned char *d;
+
+ if (had_failures(req, error)) {
+ DMWARN("%s: vpd inquiry error %x %x",
+ h->path->dev->name, req->errors, error);
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ goto out;
+ }
+
+ /* 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)) {
+ DMINFO("%s: kmalloc buffer failed",__FUNCTION__);
+ /* Temporary failure, bypass */
+ dm_pg_init_complete(h->path, MP_BYPASS_PG);
+ } else {
+ dm_enqueue_hw_workq(hwh);
+ }
+ goto out;
+ }
+
+ /*
+ * 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
+ */
+ DMWARN("%s: No target port descriptors in VPD page 0x83\n",
+ h->path->dev->name);
+ h->state = TPGS_STATE_OPTIMIZED;
+ h->tpgs = TPGS_MODE_NONE;
+ dm_pg_init_complete(h->path, 0);
+ } else {
+ DMWARN("%s: port group %02x rel port %02x",
+ h->path->dev->name, h->group_id, h->rel_port);
+ dm_enqueue_hw_workq(hwh);
+ }
+
+ out:
+ __blk_put_request(req->q, req);
+}
+
+/*
+ * Issue an INQUIRY VPD page 0x83 command
+ */
+static void submit_vpd_inquiry(struct hw_handler *hwh)
+{
+ struct alua_handler *h = hwh->context;
+ struct request *rq;
+
+ rq = prepare_req(hwh, h->buff, h->bufflen, READ);
+ if (!rq) {
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ return;
+ }
+
+ /* 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);
+
+ DMINFO("%s: submit vpd inq %x %x %x %x %x %x",
+ h->path->dev->name, rq->cmd[0], rq->cmd[1],
+ rq->cmd[2], rq->cmd[3], rq->cmd[4], rq->cmd[5]);
+
+ blk_execute_rq_nowait(rq->q, NULL, rq, 1, vpd_inquiry_endio);
+}
+
+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';
+ }
+}
+
+/*
+ * REPORT TARGET GROUP STATES endio handler
+ *
+ * Set the Target Port Group State. If the state
+ * is not 'active/optimized' we will try to activate
+ * this group by sending a 'SET TARGET GROUP STATES'
+ * command.
+ * If the state is 'offline' we will just fail the
+ * path.
+ */
+static void rtpg_endio(struct request *req, int error)
+{
+ struct hw_handler *hwh = req->end_io_data;
+ struct alua_handler *h = hwh->context;
+ struct scsi_sense_hdr sense_hdr;
+ int len, k, off, valid_states = 0, sense = 0;
+ char *ucp;
+
+ if (had_failures(req, error)) {
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ goto done;
+ }
+
+ if (status_byte(error) == CHECK_CONDITION) {
+ scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+ &sense_hdr);
+ /* Retry if not ready */
+ if (sense_hdr.sense_key == NOT_READY) {
+ DMWARN("%s: device not ready, retry",
+ h->path->dev->name);
+ dm_enqueue_hw_workq(hwh);
+ goto done;
+ }
+ /* Retry on Unit Attention */
+ sense = (sense_hdr.sense_key << 16) | (sense_hdr.asc << 8) |
+ sense_hdr.ascq;
+ if (sense == 0x62a06) {
+ DMWARN("%s: unit attention after state transition",
+ h->path->dev->name);
+ dm_enqueue_hw_workq(hwh);
+ goto done;
+ }
+ }
+
+ 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)) {
+ DMINFO("%s: kmalloc buffer failed",__FUNCTION__);
+ /* Temporary failure, bypass */
+ dm_pg_init_complete(h->path, MP_BYPASS_PG);
+ } else {
+ dm_enqueue_hw_workq(hwh);
+ }
+ goto done;
+ }
+
+ 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);
+ }
+
+ DMWARN("%s: port group %02x state %c supports %c%c%c%c%c%c",
+ h->path->dev->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 */
+ dm_enqueue_hw_workq(hwh);
+ break;
+ case TPGS_STATE_OPTIMIZED:
+ /* Path in Active/Optmized state, all done */
+ dm_pg_init_complete(h->path, 0);
+ break;
+ case TPGS_STATE_OFFLINE:
+ /* Path is offline, fail */
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ break;
+ default:
+ /* Switch path to Active/Optimized */
+ dm_enqueue_hw_workq(hwh);
+ 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 */
+ dm_pg_init_complete(h->path, 0);
+ else
+ /* Path unuseable for unavailable/offline */
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ }
+
+ done:
+ __blk_put_request(req->q, req);
+}
+
+/*
+ * Issue a REPORT TARGET GROUP STATES command.
+ */
+static void submit_rtpg(struct hw_handler *hwh)
+{
+ struct alua_handler *h = hwh->context;
+ struct request *rq;
+
+ rq = prepare_req(hwh, h->buff, h->bufflen, READ);
+ if (!rq) {
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ return;
+ }
+
+ /* 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);
+
+ blk_execute_rq_nowait(rq->q, NULL, rq, 1, rtpg_endio);
+}
+
+/*
+ * SET TARGET GROUP STATES endio handler
+ *
+ * We only have to test here if we should resubmit the command;
+ * any other error is assumed as a failure.
+ * Maybe we should analyze the sensebuffer here, too.
+ */
+static void stpg_endio(struct request *req, int error)
+{
+ struct hw_handler *hwh = req->end_io_data;
+ struct alua_handler *h = hwh->context;
+
+ switch(host_byte(error)) {
+ case DID_BUS_BUSY:
+ if (!h->retry)
+ break;
+ h->retry--;
+ case DID_REQUEUE:
+ case DID_IMM_RETRY:
+ dm_enqueue_hw_workq(hwh);
+ goto done;
+ }
+
+ if (had_failures(req, error)) {
+ if (h->tpgs & TPGS_MODE_IMPLICIT) {
+ /* Ignore errors; the array will figure it out */
+ DMWARN("%s: stpg failed %x, disabling explicit mode",
+ h->path->dev->name, error);
+ h->tpgs &= ~TPGS_MODE_EXPLICIT;
+ dm_enqueue_hw_workq(hwh);
+ } else {
+ DMWARN("%s: stpg failed %x, disable path",
+ h->path->dev->name, error);
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ }
+ } else {
+ DMWARN("%s: port group %02x new state %c",
+ h->path->dev->name, h->group_id,
+ print_alua_state(h->state) );
+ dm_pg_init_complete(h->path, 0);
+ }
+
+ done:
+ __blk_put_request(req->q, req);
+}
+
+/*
+ * 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 void submit_stpg(struct hw_handler *hwh)
+{
+ struct alua_handler *h = hwh->context;
+ struct request *rq;
+ 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 = prepare_req(hwh, h->buff, stpg_len, WRITE);
+ if (!rq) {
+ dm_pg_init_complete(h->path, MP_FAIL_PATH);
+ return;
+ }
+
+ /* 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);
+
+ blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
+}
+
+/*
+ * State machine for submitting ALUA commands
+ */
+static void alua_submit_cmd(struct hw_handler *hwh)
+{
+ struct alua_handler *h = hwh->context;
+
+ DMINFO("%s: tpgs %d group_id %d state %d",
+ h->path->dev->name, h->tpgs, h->group_id, h->state);
+
+ if (h->tpgs == TPGS_MODE_UNINITIALIZED)
+ submit_std_inquiry(hwh);
+ else if (h->tpgs & (TPGS_MODE_IMPLICIT | TPGS_MODE_EXPLICIT) &&
+ h->group_id == -1)
+ submit_vpd_inquiry(hwh);
+ else if (h->group_id != -1)
+ submit_rtpg(hwh);
+ else if (h->state != TPGS_STATE_OPTIMIZED)
+ submit_stpg(hwh);
+}
+
+/*
+ * We're currently switching the port group to be activated only and
+ * let the array figure out the rest.
+ * There may be others 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_create(struct hw_handler *hwh, unsigned argc, char **argv)
+{
+ struct alua_handler *h;
+
+ /* No arguments */
+ if (argc != 0) {
+ DMWARN("incorrect number of arguments");
+ return -EINVAL;
+ }
+
+ h = kzalloc(sizeof(*h), GFP_KERNEL);
+ if (!h)
+ return -ENOMEM;
+
+ hwh->context = h;
+ h->tpgs = TPGS_MODE_UNINITIALIZED;
+ h->group_id = -1;
+ h->rel_port = -1;
+ h->buff = h->inq;
+ h->bufflen = ALUA_INQUIRY_SIZE;
+
+ return 0;
+}
+
+static void alua_destroy(struct hw_handler *hwh)
+{
+ struct alua_handler *h = hwh->context;
+
+ if (h->buff && h->inq != h->buff)
+ kfree(h->buff);
+ kfree(h);
+ hwh->context = NULL;
+}
+
+static unsigned alua_error(struct hw_handler *hwh, struct bio *bio)
+{
+ /* Try default handler */
+ return dm_scsi_err_handler(hwh, bio);
+}
+
+static void alua_pg_init(struct hw_handler *hwh, unsigned bypassed,
+ struct dm_path *path)
+{
+ struct alua_handler *h = hwh->context;
+
+ h->path = path;
+ h->retry = 5;
+ h->state = TPGS_STATE_OPTIMIZED;
+ dm_enqueue_hw_workq(hwh);
+}
+
+static struct hw_handler_type alua_handler = {
+ .name = DM_ALUA_HWH_NAME,
+ .module = THIS_MODULE,
+ .create = alua_create,
+ .destroy = alua_destroy,
+ .pg_init = alua_pg_init,
+ .error = alua_error,
+ .workq_fn = alua_submit_cmd,
+};
+
+static int __init alua_init(void)
+{
+ int r = dm_register_hw_handler(&alua_handler);
+
+ if (r < 0) {
+ DMERR("%s: register failed %d", DM_ALUA_HWH_NAME, r);
+ return r;
+ }
+
+ DMINFO("%s: version %s loaded", DM_ALUA_HWH_NAME, DM_ALUA_HWH_VER);
+ return 0;
+}
+
+static void __exit alua_exit(void)
+{
+ int r = dm_unregister_hw_handler(&alua_handler);
+
+ if (r < 0)
+ DMERR("%s: unregister failed %d", DM_ALUA_HWH_NAME, r);
+}
+
+module_init(alua_init);
+module_exit(alua_exit);
+
+MODULE_DESCRIPTION("DM Multipath ALUA support");
+MODULE_AUTHOR("Hannes Reinecke");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DM_ALUA_HWH_VER);
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 702fcfe..cdd15c8 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -91,6 +91,7 @@ extern const unsigned char scsi_command_size[8];
#define PERSISTENT_RESERVE_OUT 0x5f
#define REPORT_LUNS 0xa0
#define MAINTENANCE_IN 0xa3
+#define MAINTENANCE_OUT 0xa4
#define MOVE_MEDIUM 0xa5
#define EXCHANGE_MEDIUM 0xa6
#define READ_12 0xa8
@@ -110,6 +111,8 @@ extern const unsigned char scsi_command_size[8];
#define SAI_READ_CAPACITY_16 0x10
/* values for maintenance in */
#define MI_REPORT_TARGET_PGS 0x0a
+/* values for maintenance out */
+#define MO_SET_TARGET_PGS 0x0a
/* Values for T10/04-262r7 */
#define ATA_16 0x85 /* 16-byte pass-thru */
--
1.5.3.2
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