[SCSI] scsi_dh: add EMC Clariion device handler

This adds support for EMC Clariions. This patch has the features that
currently exists in mainline and advanced features from Ed's patches.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/device_handler/Kconfig

@@ -24,3 +24,9 @@ config SCSI_DH_HP_SW
 	If you have a HP/COMPAQ MSA device that requires START_STOP to
 	be sent to start it and cannot upgrade the firmware then select y.
 	Otherwise, say N.
+
+config SCSI_DH_EMC
+	tristate "EMC CLARiiON Device Handler"
+	depends on SCSI_DH
+	help
+	If you have a EMC CLARiiON select y. Otherwise, say N.

drivers/scsi/device_handler/Makefile

@@ -4,3 +4,4 @@
 obj-$(CONFIG_SCSI_DH)		+= scsi_dh.o
 obj-$(CONFIG_SCSI_DH_RDAC)	+= scsi_dh_rdac.o
 obj-$(CONFIG_SCSI_DH_HP_SW)	+= scsi_dh_hp_sw.o
+obj-$(CONFIG_SCSI_DH_EMC)	+= scsi_dh_emc.o

drivers/scsi/device_handler/scsi_dh_emc.c

+/*
+ * Target driver for EMC CLARiiON AX/CX-series hardware.
+ * Based on code from Lars Marowsky-Bree <lmb@suse.de>
+ * and Ed Goggin <egoggin@emc.com>.
+ *
+ * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2006 Mike Christie
+ *
+ * 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, 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <scsi/scsi.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_dh.h>
+#include <scsi/scsi_device.h>
+
+#define CLARIION_NAME			"emc_clariion"
+
+#define CLARIION_TRESPASS_PAGE		0x22
+#define CLARIION_BUFFER_SIZE		0x80
+#define CLARIION_TIMEOUT		(60 * HZ)
+#define CLARIION_RETRIES		3
+#define CLARIION_UNBOUND_LU		-1
+
+static unsigned char long_trespass[] = {
+	0, 0, 0, 0,
+	CLARIION_TRESPASS_PAGE,	/* Page code */
+	0x09,			/* Page length - 2 */
+	0x81,			/* Trespass code + Honor reservation bit */
+	0xff, 0xff,		/* Trespass target */
+	0, 0, 0, 0, 0, 0	/* Reserved bytes / unknown */
+};
+
+static unsigned char long_trespass_hr[] = {
+	0, 0, 0, 0,
+	CLARIION_TRESPASS_PAGE,	/* Page code */
+	0x09,			/* Page length - 2 */
+	0x01,			/* Trespass code + Honor reservation bit */
+	0xff, 0xff,		/* Trespass target */
+	0, 0, 0, 0, 0, 0	/* Reserved bytes / unknown */
+};
+
+static unsigned char short_trespass[] = {
+	0, 0, 0, 0,
+	CLARIION_TRESPASS_PAGE,	/* Page code */
+	0x02,			/* Page length - 2 */
+	0x81,			/* Trespass code + Honor reservation bit */
+	0xff,			/* Trespass target */
+};
+
+static unsigned char short_trespass_hr[] = {
+	0, 0, 0, 0,
+	CLARIION_TRESPASS_PAGE,	/* Page code */
+	0x02,			/* Page length - 2 */
+	0x01,			/* Trespass code + Honor reservation bit */
+	0xff,			/* Trespass target */
+};
+
+struct clariion_dh_data {
+	/*
+	 * Use short trespass command (FC-series) or the long version
+	 * (default for AX/CX CLARiiON arrays).
+	 */
+	unsigned short_trespass;
+	/*
+	 * Whether or not (default) to honor SCSI reservations when
+	 * initiating a switch-over.
+	 */
+	unsigned hr;
+	/* I/O buffer for both MODE_SELECT and INQUIRY commands. */
+	char buffer[CLARIION_BUFFER_SIZE];
+	/*
+	 * SCSI sense buffer for commands -- assumes serial issuance
+	 * and completion sequence of all commands for same multipath.
+	 */
+	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
+	/* which SP (A=0,B=1,UNBOUND=-1) is dflt SP for path's mapped dev */
+	int default_sp;
+	/* which SP (A=0,B=1,UNBOUND=-1) is active for path's mapped dev */
+	int current_sp;
+};
+
+static inline struct clariion_dh_data
+			*get_clariion_data(struct scsi_device *sdev)
+{
+	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
+	BUG_ON(scsi_dh_data == NULL);
+	return ((struct clariion_dh_data *) scsi_dh_data->buf);
+}
+
+/*
+ * Parse MODE_SELECT cmd reply.
+ */
+static int trespass_endio(struct scsi_device *sdev, int result)
+{
+	int err = SCSI_DH_OK;
+	struct scsi_sense_hdr sshdr;
+	struct clariion_dh_data *csdev = get_clariion_data(sdev);
+	char *sense = csdev->sense;
+
+	if (status_byte(result) == CHECK_CONDITION &&
+	    scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)) {
+		sdev_printk(KERN_ERR, sdev, "Found valid sense data 0x%2x, "
+			    "0x%2x, 0x%2x while sending CLARiiON trespass "
+			    "command.\n", sshdr.sense_key, sshdr.asc,
+			     sshdr.ascq);
+
+		if ((sshdr.sense_key == 0x05) && (sshdr.asc == 0x04) &&
+		     (sshdr.ascq == 0x00)) {
+			/*
+			 * Array based copy in progress -- do not send
+			 * mode_select or copy will be aborted mid-stream.
+			 */
+			sdev_printk(KERN_INFO, sdev, "Array Based Copy in "
+				    "progress while sending CLARiiON trespass "
+				    "command.\n");
+			err = SCSI_DH_DEV_TEMP_BUSY;
+		} else if ((sshdr.sense_key == 0x02) && (sshdr.asc == 0x04) &&
+			    (sshdr.ascq == 0x03)) {
+			/*
+			 * LUN Not Ready - Manual Intervention Required
+			 * indicates in-progress ucode upgrade (NDU).
+			 */
+			sdev_printk(KERN_INFO, sdev, "Detected in-progress "
+				    "ucode upgrade NDU operation while sending "
+				    "CLARiiON trespass command.\n");
+			err = SCSI_DH_DEV_TEMP_BUSY;
+		} else
+			err = SCSI_DH_DEV_FAILED;
+	} else if (result) {
+		sdev_printk(KERN_ERR, sdev, "Error 0x%x while sending "
+			    "CLARiiON trespass command.\n", result);
+		err = SCSI_DH_IO;
+	}
+
+	return err;
+}
+
+static int parse_sp_info_reply(struct scsi_device *sdev, int result,
+		int *default_sp, int *current_sp, int *new_current_sp)
+{
+	int err = SCSI_DH_OK;
+	struct clariion_dh_data *csdev = get_clariion_data(sdev);
+
+	if (result == 0) {
+		/* check for in-progress ucode upgrade (NDU) */
+		if (csdev->buffer[48] != 0) {
+			sdev_printk(KERN_NOTICE, sdev, "Detected in-progress "
+			       "ucode upgrade NDU operation while finding "
+			       "current active SP.");
+			err = SCSI_DH_DEV_TEMP_BUSY;
+		} else {
+			*default_sp = csdev->buffer[5];
+
+			if (csdev->buffer[4] == 2)
+				/* SP for path is current */
+				*current_sp = csdev->buffer[8];
+			else {
+				if (csdev->buffer[4] == 1)
+					/* SP for this path is NOT current */
+					if (csdev->buffer[8] == 0)
+						*current_sp = 1;
+					else
+						*current_sp = 0;
+				else
+					/* unbound LU or LUNZ */
+					*current_sp = CLARIION_UNBOUND_LU;
+			}
+			*new_current_sp =  csdev->buffer[8];
+		}
+	} else {
+		struct scsi_sense_hdr sshdr;
+
+		err = SCSI_DH_IO;
+
+		if (scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
+							   &sshdr))
+			sdev_printk(KERN_ERR, sdev, "Found valid sense data "
+			      "0x%2x, 0x%2x, 0x%2x while finding current "
+			      "active SP.", sshdr.sense_key, sshdr.asc,
+			      sshdr.ascq);
+		else
+			sdev_printk(KERN_ERR, sdev, "Error 0x%x finding "
+			      "current active SP.", result);
+	}
+
+	return err;
+}
+
+static int sp_info_endio(struct scsi_device *sdev, int result,
+					int mode_select_sent, int *done)
+{
+	struct clariion_dh_data *csdev = get_clariion_data(sdev);
+	int err_flags, default_sp, current_sp, new_current_sp;
+
+	err_flags = parse_sp_info_reply(sdev, result, &default_sp,
+					     &current_sp, &new_current_sp);
+
+	if (err_flags != SCSI_DH_OK)
+		goto done;
+
+	if (mode_select_sent) {
+		csdev->default_sp = default_sp;
+		csdev->current_sp = current_sp;
+	} else {
+		/*
+		 * Issue the actual module_selec request IFF either
+		 * (1) we do not know the identity of the current SP OR
+		 * (2) what we think we know is actually correct.
+		 */
+		if ((current_sp != CLARIION_UNBOUND_LU) &&
+		    (new_current_sp != current_sp)) {
+
+			csdev->default_sp = default_sp;
+			csdev->current_sp = current_sp;
+
+			sdev_printk(KERN_INFO, sdev, "Ignoring path group "
+			       "switch-over command for CLARiiON SP%s since "
+			       " mapped device is already initialized.",
+			       current_sp ? "B" : "A");
+			if (done)
+				*done = 1; /* as good as doing it */
+		}
+	}
+done:
+	return err_flags;
+}
+
+/*
+* Get block request for REQ_BLOCK_PC command issued to path.  Currently
+* limited to MODE_SELECT (trespass) and INQUIRY (VPD page 0xC0) commands.
+*
+* Uses data and sense buffers in hardware handler context structure and
+* assumes serial servicing of commands, both issuance and completion.
+*/
+static struct request *get_req(struct scsi_device *sdev, int cmd)
+{
+	struct clariion_dh_data *csdev = get_clariion_data(sdev);
+	struct request *rq;
+	unsigned char *page22;
+	int len = 0;
+
+	rq = blk_get_request(sdev->request_queue,
+			(cmd == MODE_SELECT) ? WRITE : READ, GFP_ATOMIC);
+	if (!rq) {
+		sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
+		return NULL;
+	}
+
+	memset(&rq->cmd, 0, BLK_MAX_CDB);
+	rq->cmd[0] = cmd;
+	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
+
+	switch (cmd) {
+	case MODE_SELECT:
+		if (csdev->short_trespass) {
+			page22 = csdev->hr ? short_trespass_hr : short_trespass;
+			len = sizeof(short_trespass);
+		} else {
+			page22 = csdev->hr ? long_trespass_hr : long_trespass;
+			len = sizeof(long_trespass);
+		}
+		/*
+		 * Can't DMA from kernel BSS -- must copy selected trespass
+		 * command mode page contents to context buffer which is
+		 * allocated by kmalloc.
+		 */
+		BUG_ON((len > CLARIION_BUFFER_SIZE));
+		memcpy(csdev->buffer, page22, len);
+		rq->cmd_flags |= REQ_RW;
+		rq->cmd[1] = 0x10;
+		break;
+	case INQUIRY:
+		rq->cmd[1] = 0x1;
+		rq->cmd[2] = 0xC0;
+		len = CLARIION_BUFFER_SIZE;
+		memset(csdev->buffer, 0, CLARIION_BUFFER_SIZE);
+		break;
+	default:
+		BUG_ON(1);
+		break;
+	}
+
+	rq->cmd[4] = len;
+	rq->cmd_type = REQ_TYPE_BLOCK_PC;
+	rq->cmd_flags |= REQ_FAILFAST;
+	rq->timeout = CLARIION_TIMEOUT;
+	rq->retries = CLARIION_RETRIES;
+
+	rq->sense = csdev->sense;
+	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
+	rq->sense_len = 0;
+
+	if (blk_rq_map_kern(sdev->request_queue, rq, csdev->buffer,
+							len, GFP_ATOMIC)) {
+		__blk_put_request(rq->q, rq);
+		return NULL;
+	}
+
+	return rq;
+}
+
+static int send_cmd(struct scsi_device *sdev, int cmd)
+{
+	struct request *rq = get_req(sdev, cmd);
+
+	if (!rq)
+		return SCSI_DH_RES_TEMP_UNAVAIL;
+
+	return blk_execute_rq(sdev->request_queue, NULL, rq, 1);
+}
+
+static int clariion_activate(struct scsi_device *sdev)
+{
+	int result, done = 0;
+
+	result = send_cmd(sdev, INQUIRY);
+	result = sp_info_endio(sdev, result, 0, &done);
+	if (result || done)
+		goto done;
+
+	result = send_cmd(sdev, MODE_SELECT);
+	result = trespass_endio(sdev, result);
+	if (result)
+		goto done;
+
+	result = send_cmd(sdev, INQUIRY);
+	result = sp_info_endio(sdev, result, 1, NULL);
+done:
+	return result;
+}
+
+static int clariion_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 == 0x03)
+			/*
+			 * 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.
+			 *
+			 * Can return FAILED only when we want the error
+			 * recovery process to kick in.
+			 */
+			return SUCCESS;
+		break;
+	case ILLEGAL_REQUEST:
+		if (sense_hdr->asc == 0x25 && sense_hdr->ascq == 0x01)
+			/*
+			 * 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.)
+			 *
+			 * Can return FAILED only when we want the error
+			 * recovery process to kick in.
+			 */
+			return SUCCESS;
+		break;
+	case UNIT_ATTENTION:
+		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
+			/*
+			 * Unit Attention Code. This is the first IO
+			 * to the new path, so just retry.
+			 */
+			return NEEDS_RETRY;
+		break;
+	}
+
+	/* success just means we do not care what scsi-ml does */
+	return SUCCESS;
+}
+
+static const struct {
+	char *vendor;
+	char *model;
+} clariion_dev_list[] = {
+	{"DGC", "RAID"},
+	{"DGC", "DISK"},
+	{NULL, NULL},
+};
+
+static int clariion_bus_notify(struct notifier_block *, unsigned long, void *);
+
+static struct scsi_device_handler clariion_dh = {
+	.name		= CLARIION_NAME,
+	.module		= THIS_MODULE,
+	.nb.notifier_call = clariion_bus_notify,
+	.check_sense	= clariion_check_sense,
+	.activate	= clariion_activate,
+};
+
+/*
+ * TODO: need some interface so we can set trespass values
+ */
+static int clariion_bus_notify(struct notifier_block *nb,
+				unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_dh_data *scsi_dh_data;
+	struct clariion_dh_data *h;
+	int i, found = 0;
+	unsigned long flags;
+
+	if (action == BUS_NOTIFY_ADD_DEVICE) {
+		for (i = 0; clariion_dev_list[i].vendor; i++) {
+			if (!strncmp(sdev->vendor, clariion_dev_list[i].vendor,
+				     strlen(clariion_dev_list[i].vendor)) &&
+			    !strncmp(sdev->model, clariion_dev_list[i].model,
+				     strlen(clariion_dev_list[i].model))) {
+				found = 1;
+				break;
+			}
+		}
+		if (!found)
+			goto out;
+
+		scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
+				+ sizeof(*h) , GFP_KERNEL);
+		if (!scsi_dh_data) {
+			sdev_printk(KERN_ERR, sdev, "Attach failed %s.\n",
+				    CLARIION_NAME);
+			goto out;
+		}
+
+		scsi_dh_data->scsi_dh = &clariion_dh;
+		h = (struct clariion_dh_data *) scsi_dh_data->buf;
+		h->default_sp = CLARIION_UNBOUND_LU;
+		h->current_sp = CLARIION_UNBOUND_LU;
+
+		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, "Attached %s.\n", CLARIION_NAME);
+		try_module_get(THIS_MODULE);
+
+	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
+		if (sdev->scsi_dh_data == NULL ||
+				sdev->scsi_dh_data->scsi_dh != &clariion_dh)
+			goto out;
+
+		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);
+
+		sdev_printk(KERN_NOTICE, sdev, "Dettached %s.\n",
+			    CLARIION_NAME);
+
+		kfree(scsi_dh_data);
+		module_put(THIS_MODULE);
+	}
+
+out:
+	return 0;
+}
+
+static int __init clariion_init(void)
+{
+	int r;
+
+	r = scsi_register_device_handler(&clariion_dh);
+	if (r != 0)
+		printk(KERN_ERR "Failed to register scsi device handler.");
+	return r;
+}
+
+static void __exit clariion_exit(void)
+{
+	scsi_unregister_device_handler(&clariion_dh);
+}
+
+module_init(clariion_init);
+module_exit(clariion_exit);
+
+MODULE_DESCRIPTION("EMC CX/AX/FC-family driver");
+MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, Chandra Seetharaman <sekharan@us.ibm.com>");
+MODULE_LICENSE("GPL");