drivers/md/dm-emc.c - kernel/msm-4.9 - Gitiles

 /*
  * 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 void emc_endio(struct bio *bio, int error)
 {
 	struct dm_path *path = bio->bi_private;

 	/* 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);
 }

 static struct bio *get_failover_bio(struct dm_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: bio_add_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 dm_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;
 	}

 	blk_rq_append_bio(q, rq, bio);

 	rq->sense = h->sense;
 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 	rq->sense_len = 0;

 	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 dm_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 dm_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 = kzalloc(sizeof(*h), GFP_KERNEL);

 	if (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");
	/*
	* 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 void emc_endio(struct bio *bio, int error)
	{
	struct dm_path *path = bio->bi_private;

	/* 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);
	}

	static struct bio get_failover_bio(struct dm_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: bio_add_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 dm_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;
	}

	blk_rq_append_bio(q, rq, bio);

	rq->sense = h->sense;
	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
	rq->sense_len = 0;

	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 dm_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 dm_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 = kzalloc(sizeof(h), GFP_KERNEL);

	if (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");