/*
* Copyright (C) 2004 SUSE LINUX Products GmbH. All rights reserved.
* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*
* Multipath support for EMC CLARiiON AX/CX-series hardware.
*/
#include "dm.h"
#include "dm-hw-handler.h"
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#define DM_MSG_PREFIX "multipath emc"
struct emc_handler {
spinlock_t lock;
/* Whether we should send the short trespass command (FC-series)
* or the long version (default for AX/CX CLARiiON arrays). */
unsigned short_trespass;
/* Whether or not to honor SCSI reservations when initiating a
* switch-over. Default: Don't. */
unsigned hr;
unsigned char sense[SCSI_SENSE_BUFFERSIZE];
};
#define TRESPASS_PAGE 0x22
#define EMC_FAILOVER_TIMEOUT (60 * HZ)
/* Code borrowed from dm-lsi-rdac by Mike Christie */
static inline void free_bio(struct bio *bio)
{
__free_page(bio->bi_io_vec[0].bv_page);
bio_put(bio);
}
static int emc_endio(struct bio *bio, unsigned int bytes_done, int error)
{
struct path *path = bio->bi_private;
if (bio->bi_size)
return 1;
/* We also need to look at the sense keys here whether or not to
* switch to the next PG etc.
*
* For now simple logic: either it works or it doesn't.
*/
if (error)
dm_pg_init_complete(path, MP_FAIL_PATH);
else
dm_pg_init_complete(path, 0);
/* request is freed in block layer */
free_bio(bio);
return 0;
}
static struct bio *get_failover_bio(struct path *path, unsigned data_size)
{
struct bio *bio;
struct page *page;
bio = bio_alloc(GFP_ATOMIC, 1);
if (!bio) {
DMERR("get_failover_bio: bio_alloc() failed.");
return NULL;
}
bio->bi_rw |= (1 << BIO_RW);
bio->bi_bdev = path->dev->bdev;
bio->bi_sector = 0;
bio->bi_private = path;
bio->bi_end_io = emc_endio;
page = alloc_page(GFP_ATOMIC);
if (!page) {
DMERR("get_failover_bio: alloc_page() failed.");
bio_put(bio);
return NULL;
}
if (bio_add_page(bio, page, data_size, 0) != data_size) {
DMERR("get_failover_bio: alloc_page() failed.");
__free_page(page);
bio_put(bio);
return NULL;
}
return bio;
}
static struct request *get_failover_req(struct emc_handler *h,
struct bio *bio, struct path *path)
{
struct request *rq;
struct block_device *bdev = bio->bi_bdev;
struct request_queue *q = bdev_get_queue(bdev);
/* FIXME: Figure out why it fails with GFP_ATOMIC. */
rq = blk_get_request(q, WRITE, __GFP_WAIT);
if (!rq) {
DMERR("get_failover_req: blk_get_request failed");
return NULL;
}
rq->bio = rq->biotail = bio;
blk_rq_bio_prep(q, rq, bio);
rq->rq_disk = bdev->bd_contains->bd_disk;
/* bio backed don't set data */
rq->buffer = rq->data = NULL;
/* rq data_len used for pc cmd's request_bufflen */
rq->data_len = bio->bi_size;
rq->sense = h->sense;
memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
rq->sense_len = 0;
memset(&rq->cmd, 0, BLK_MAX_CDB);
rq->timeout = EMC_FAILOVER_TIMEOUT;
rq->cmd_type = REQ_TYPE_BLOCK_PC;
rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
return rq;
}
static struct request *emc_trespass_get(struct emc_handler *h,
struct path *path)
{
struct bio *bio;
struct request *rq;
unsigned char *page22;
unsigned char long_trespass_pg[] = {
0, 0, 0, 0,
TRESPASS_PAGE, /* Page code */
0x09, /* Page length - 2 */
h->hr ? 0x01 : 0x81, /* Trespass code + Honor reservation bit */
0xff, 0xff, /* Trespass target */
0, 0, 0, 0, 0, 0 /* Reserved bytes / unknown */
};
unsigned char short_trespass_pg[] = {
0, 0, 0, 0,
TRESPASS_PAGE, /* Page code */
0x02, /* Page length - 2 */
h->hr ? 0x01 : 0x81, /* Trespass code + Honor reservation bit */
0xff, /* Trespass target */
};
unsigned data_size = h->short_trespass ? sizeof(short_trespass_pg) :
sizeof(long_trespass_pg);
/* get bio backing */
if (data_size > PAGE_SIZE)
/* this should never happen */
return NULL;
bio = get_failover_bio(path, data_size);
if (!bio) {
DMERR("emc_trespass_get: no bio");
return NULL;
}
page22 = (unsigned char *)bio_data(bio);
memset(page22, 0, data_size);
memcpy(page22, h->short_trespass ?
short_trespass_pg : long_trespass_pg, data_size);
/* get request for block layer packet command */
rq = get_failover_req(h, bio, path);
if (!rq) {
DMERR("emc_trespass_get: no rq");
free_bio(bio);
return NULL;
}
/* Prepare the command. */
rq->cmd[0] = MODE_SELECT;
rq->cmd[1] = 0x10;
rq->cmd[4] = data_size;
rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
return rq;
}
static void emc_pg_init(struct hw_handler *hwh, unsigned bypassed,
struct path *path)
{
struct request *rq;
struct request_queue *q = bdev_get_queue(path->dev->bdev);
/*
* We can either blindly init the pg (then look at the sense),
* or we can send some commands to get the state here (then
* possibly send the fo cmnd), or we can also have the
* initial state passed into us and then get an update here.
*/
if (!q) {
DMINFO("emc_pg_init: no queue");
goto fail_path;
}
/* FIXME: The request should be pre-allocated. */
rq = emc_trespass_get(hwh->context, path);
if (!rq) {
DMERR("emc_pg_init: no rq");
goto fail_path;
}
DMINFO("emc_pg_init: sending switch-over command");
elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 1);
return;
fail_path:
dm_pg_init_complete(path, MP_FAIL_PATH);
}
static struct emc_handler *alloc_emc_handler(void)
{
struct emc_handler *h = kmalloc(sizeof(*h), GFP_KERNEL);
if (h) {
memset(h, 0, sizeof(*h));
spin_lock_init(&h->lock);
}
return h;
}
static int emc_create(struct hw_handler *hwh, unsigned argc, char **argv)
{
struct emc_handler *h;
unsigned hr, short_trespass;
if (argc == 0) {
/* No arguments: use defaults */
hr = 0;
short_trespass = 0;
} else if (argc != 2) {
DMWARN("incorrect number of arguments");
return -EINVAL;
} else {
if ((sscanf(argv[0], "%u", &short_trespass) != 1)
|| (short_trespass > 1)) {
DMWARN("invalid trespass mode selected");
return -EINVAL;
}
if ((sscanf(argv[1], "%u", &hr) != 1)
|| (hr > 1)) {
DMWARN("invalid honor reservation flag selected");
return -EINVAL;
}
}
h = alloc_emc_handler();
if (!h)
return -ENOMEM;
hwh->context = h;
if ((h->short_trespass = short_trespass))
DMWARN("short trespass command will be send");
else
DMWARN("long trespass command will be send");
if ((h->hr = hr))
DMWARN("honor reservation bit will be set");
else
DMWARN("honor reservation bit will not be set (default)");
return 0;
}
static void emc_destroy(struct hw_handler *hwh)
{
struct emc_handler *h = (struct emc_handler *) hwh->context;
kfree(h);
hwh->context = NULL;
}
static unsigned emc_error(struct hw_handler *hwh, struct bio *bio)
{
/* FIXME: Patch from axboe still missing */
#if 0
int sense;
if (bio->bi_error & BIO_SENSE) {
sense = bio->bi_error & 0xffffff; /* sense key / asc / ascq */
if (sense == 0x020403) {
/* LUN Not Ready - Manual Intervention Required
* indicates this is a passive path.
*
* FIXME: However, if this is seen and EVPD C0
* indicates that this is due to a NDU in
* progress, we should set FAIL_PATH too.
* This indicates we might have to do a SCSI
* inquiry in the end_io path. Ugh. */
return MP_BYPASS_PG | MP_RETRY_IO;
} else if (sense == 0x052501) {
/* An array based copy is in progress. Do not
* fail the path, do not bypass to another PG,
* do not retry. Fail the IO immediately.
* (Actually this is the same conclusion as in
* the default handler, but lets make sure.) */
return 0;
} else if (sense == 0x062900) {
/* Unit Attention Code. This is the first IO
* to the new path, so just retry. */
return MP_RETRY_IO;
}
}
#endif
/* Try default handler */
return dm_scsi_err_handler(hwh, bio);
}
static struct hw_handler_type emc_hwh = {
.name = "emc",
.module = THIS_MODULE,
.create = emc_create,
.destroy = emc_destroy,
.pg_init = emc_pg_init,
.error = emc_error,
};
static int __init dm_emc_init(void)
{
int r = dm_register_hw_handler(&emc_hwh);
if (r < 0)
DMERR("register failed %d", r);
DMINFO("version 0.0.3 loaded");
return r;
}
static void __exit dm_emc_exit(void)
{
int r = dm_unregister_hw_handler(&emc_hwh);
if (r < 0)
DMERR("unregister failed %d", r);
}
module_init(dm_emc_init);
module_exit(dm_emc_exit);
MODULE_DESCRIPTION(DM_NAME " EMC CX/AX/FC-family multipath");
MODULE_AUTHOR("Lars Marowsky-Bree <lmb@suse.de>");
MODULE_LICENSE("GPL");
