IB: Add SCSI RDMA Protocol (SRP) initiator

Add an InfiniBand SCSI RDMA Protocol (SRP) initiator. This driver is
used to talk talk to InfiniBand SRP targets (storage devices).

Signed-off-by: Roland Dreier <[e-mail]>

drivers/infiniband/Kconfig

···
 
 source "drivers/infiniband/ulp/ipoib/Kconfig"
 
+source "drivers/infiniband/ulp/srp/Kconfig"
+
 endmenu

drivers/infiniband/Makefile

···
 obj-$(CONFIG_INFINIBAND)		+= core/
 obj-$(CONFIG_INFINIBAND_MTHCA)		+= hw/mthca/
 obj-$(CONFIG_INFINIBAND_IPOIB)		+= ulp/ipoib/
+obj-$(CONFIG_INFINIBAND_SRP)		+= ulp/srp/

drivers/infiniband/ulp/srp/Kbuild

···
+obj-$(CONFIG_INFINIBAND_SRP)			+= ib_srp.o

drivers/infiniband/ulp/srp/Kconfig

···
+config INFINIBAND_SRP
+	tristate "InfiniBand SCSI RDMA Protocol"
+	depends on INFINIBAND && SCSI
+	---help---
+	  Support for the SCSI RDMA Protocol over InfiniBand.  This
+	  allows you to access storage devices that speak SRP over
+	  InfiniBand.
+
+	  The SRP protocol is defined by the INCITS T10 technical
+	  committee.  See <http://www.t10.org/>.
+

drivers/infiniband/ulp/srp/ib_srp.c

···
+/*
+ * Copyright (c) 2005 Cisco Systems.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * $Id: ib_srp.c 3932 2005-11-01 17:19:29Z roland $
+ */
+
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/parser.h>
+#include <linux/random.h>
+
+#include <asm/atomic.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/srp.h>
+
+#include <rdma/ib_cache.h>
+
+#include "ib_srp.h"
+
+#define DRV_NAME	"ib_srp"
+#define PFX		DRV_NAME ": "
+#define DRV_VERSION	"0.2"
+#define DRV_RELDATE	"November 1, 2005"
+
+MODULE_AUTHOR("Roland Dreier");
+MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol initiator "
+		   "v" DRV_VERSION " (" DRV_RELDATE ")");
+MODULE_LICENSE("Dual BSD/GPL");
+
+static int topspin_workarounds = 1;
+
+module_param(topspin_workarounds, int, 0444);
+MODULE_PARM_DESC(topspin_workarounds,
+		 "Enable workarounds for Topspin/Cisco SRP target bugs if != 0");
+
+static const u8 topspin_oui[3] = { 0x00, 0x05, 0xad };
+
+static void srp_add_one(struct ib_device *device);
+static void srp_remove_one(struct ib_device *device);
+static void srp_completion(struct ib_cq *cq, void *target_ptr);
+static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event);
+
+static struct ib_client srp_client = {
+	.name   = "srp",
+	.add    = srp_add_one,
+	.remove = srp_remove_one
+};
+
+static inline struct srp_target_port *host_to_target(struct Scsi_Host *host)
+{
+	return (struct srp_target_port *) host->hostdata;
+}
+
+static const char *srp_target_info(struct Scsi_Host *host)
+{
+	return host_to_target(host)->target_name;
+}
+
+static struct srp_iu *srp_alloc_iu(struct srp_host *host, size_t size,
+				   gfp_t gfp_mask,
+				   enum dma_data_direction direction)
+{
+	struct srp_iu *iu;
+
+	iu = kmalloc(sizeof *iu, gfp_mask);
+	if (!iu)
+		goto out;
+
+	iu->buf = kzalloc(size, gfp_mask);
+	if (!iu->buf)
+		goto out_free_iu;
+
+	iu->dma = dma_map_single(host->dev->dma_device, iu->buf, size, direction);
+	if (dma_mapping_error(iu->dma))
+		goto out_free_buf;
+
+	iu->size      = size;
+	iu->direction = direction;
+
+	return iu;
+
+out_free_buf:
+	kfree(iu->buf);
+out_free_iu:
+	kfree(iu);
+out:
+	return NULL;
+}
+
+static void srp_free_iu(struct srp_host *host, struct srp_iu *iu)
+{
+	if (!iu)
+		return;
+
+	dma_unmap_single(host->dev->dma_device, iu->dma, iu->size, iu->direction);
+	kfree(iu->buf);
+	kfree(iu);
+}
+
+static void srp_qp_event(struct ib_event *event, void *context)
+{
+	printk(KERN_ERR PFX "QP event %d\n", event->event);
+}
+
+static int srp_init_qp(struct srp_target_port *target,
+		       struct ib_qp *qp)
+{
+	struct ib_qp_attr *attr;
+	int ret;
+
+	attr = kmalloc(sizeof *attr, GFP_KERNEL);
+	if (!attr)
+		return -ENOMEM;
+
+	ret = ib_find_cached_pkey(target->srp_host->dev,
+				  target->srp_host->port,
+				  be16_to_cpu(target->path.pkey),
+				  &attr->pkey_index);
+	if (ret)
+		goto out;
+
+	attr->qp_state        = IB_QPS_INIT;
+	attr->qp_access_flags = (IB_ACCESS_REMOTE_READ |
+				    IB_ACCESS_REMOTE_WRITE);
+	attr->port_num        = target->srp_host->port;
+
+	ret = ib_modify_qp(qp, attr,
+			   IB_QP_STATE		|
+			   IB_QP_PKEY_INDEX	|
+			   IB_QP_ACCESS_FLAGS	|
+			   IB_QP_PORT);
+
+out:
+	kfree(attr);
+	return ret;
+}
+
+static int srp_create_target_ib(struct srp_target_port *target)
+{
+	struct ib_qp_init_attr *init_attr;
+	int ret;
+
+	init_attr = kzalloc(sizeof *init_attr, GFP_KERNEL);
+	if (!init_attr)
+		return -ENOMEM;
+
+	target->cq = ib_create_cq(target->srp_host->dev, srp_completion,
+				  NULL, target, SRP_CQ_SIZE);
+	if (IS_ERR(target->cq)) {
+		ret = PTR_ERR(target->cq);
+		goto out;
+	}
+
+	ib_req_notify_cq(target->cq, IB_CQ_NEXT_COMP);
+
+	init_attr->event_handler       = srp_qp_event;
+	init_attr->cap.max_send_wr     = SRP_SQ_SIZE;
+	init_attr->cap.max_recv_wr     = SRP_RQ_SIZE;
+	init_attr->cap.max_recv_sge    = 1;
+	init_attr->cap.max_send_sge    = 1;
+	init_attr->sq_sig_type         = IB_SIGNAL_ALL_WR;
+	init_attr->qp_type             = IB_QPT_RC;
+	init_attr->send_cq             = target->cq;
+	init_attr->recv_cq             = target->cq;
+
+	target->qp = ib_create_qp(target->srp_host->pd, init_attr);
+	if (IS_ERR(target->qp)) {
+		ret = PTR_ERR(target->qp);
+		ib_destroy_cq(target->cq);
+		goto out;
+	}
+
+	ret = srp_init_qp(target, target->qp);
+	if (ret) {
+		ib_destroy_qp(target->qp);
+		ib_destroy_cq(target->cq);
+		goto out;
+	}
+
+out:
+	kfree(init_attr);
+	return ret;
+}
+
+static void srp_free_target_ib(struct srp_target_port *target)
+{
+	int i;
+
+	ib_destroy_qp(target->qp);
+	ib_destroy_cq(target->cq);
+
+	for (i = 0; i < SRP_RQ_SIZE; ++i)
+		srp_free_iu(target->srp_host, target->rx_ring[i]);
+	for (i = 0; i < SRP_SQ_SIZE + 1; ++i)
+		srp_free_iu(target->srp_host, target->tx_ring[i]);
+}
+
+static void srp_path_rec_completion(int status,
+				    struct ib_sa_path_rec *pathrec,
+				    void *target_ptr)
+{
+	struct srp_target_port *target = target_ptr;
+
+	target->status = status;
+	if (status)
+		printk(KERN_ERR PFX "Got failed path rec status %d\n", status);
+	else
+		target->path = *pathrec;
+	complete(&target->done);
+}
+
+static int srp_lookup_path(struct srp_target_port *target)
+{
+	target->path.numb_path = 1;
+
+	init_completion(&target->done);
+
+	target->path_query_id = ib_sa_path_rec_get(target->srp_host->dev,
+						   target->srp_host->port,
+						   &target->path,
+						   IB_SA_PATH_REC_DGID		|
+						   IB_SA_PATH_REC_SGID		|
+						   IB_SA_PATH_REC_NUMB_PATH	|
+						   IB_SA_PATH_REC_PKEY,
+						   SRP_PATH_REC_TIMEOUT_MS,
+						   GFP_KERNEL,
+						   srp_path_rec_completion,
+						   target, &target->path_query);
+	if (target->path_query_id < 0)
+		return target->path_query_id;
+
+	wait_for_completion(&target->done);
+
+	if (target->status < 0)
+		printk(KERN_WARNING PFX "Path record query failed\n");
+
+	return target->status;
+}
+
+static int srp_send_req(struct srp_target_port *target)
+{
+	struct {
+		struct ib_cm_req_param param;
+		struct srp_login_req   priv;
+	} *req = NULL;
+	int status;
+
+	req = kzalloc(sizeof *req, GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	req->param.primary_path 	      = &target->path;
+	req->param.alternate_path 	      = NULL;
+	req->param.service_id 		      = target->service_id;
+	req->param.qp_num 		      = target->qp->qp_num;
+	req->param.qp_type 		      = target->qp->qp_type;
+	req->param.private_data 	      = &req->priv;
+	req->param.private_data_len 	      = sizeof req->priv;
+	req->param.flow_control 	      = 1;
+
+	get_random_bytes(&req->param.starting_psn, 4);
+	req->param.starting_psn 	     &= 0xffffff;
+
+	/*
+	 * Pick some arbitrary defaults here; we could make these
+	 * module parameters if anyone cared about setting them.
+	 */
+	req->param.responder_resources	      = 4;
+	req->param.remote_cm_response_timeout = 20;
+	req->param.local_cm_response_timeout  = 20;
+	req->param.retry_count 		      = 7;
+	req->param.rnr_retry_count 	      = 7;
+	req->param.max_cm_retries 	      = 15;
+
+	req->priv.opcode     	= SRP_LOGIN_REQ;
+	req->priv.tag        	= 0;
+	req->priv.req_it_iu_len = cpu_to_be32(SRP_MAX_IU_LEN);
+	req->priv.req_buf_fmt 	= cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
+					      SRP_BUF_FORMAT_INDIRECT);
+	memcpy(req->priv.initiator_port_id, target->srp_host->initiator_port_id, 16);
+	/*
+	 * Topspin/Cisco SRP targets will reject our login unless we
+	 * zero out the first 8 bytes of our initiator port ID.  The
+	 * second 8 bytes must be our local node GUID, but we always
+	 * use that anyway.
+	 */
+	if (topspin_workarounds && !memcmp(&target->ioc_guid, topspin_oui, 3)) {
+		printk(KERN_DEBUG PFX "Topspin/Cisco initiator port ID workaround "
+		       "activated for target GUID %016llx\n",
+		       (unsigned long long) be64_to_cpu(target->ioc_guid));
+		memset(req->priv.initiator_port_id, 0, 8);
+	}
+	memcpy(req->priv.target_port_id,     &target->id_ext, 8);
+	memcpy(req->priv.target_port_id + 8, &target->ioc_guid, 8);
+
+	status = ib_send_cm_req(target->cm_id, &req->param);
+
+	kfree(req);
+
+	return status;
+}
+
+static void srp_disconnect_target(struct srp_target_port *target)
+{
+	/* XXX should send SRP_I_LOGOUT request */
+
+	init_completion(&target->done);
+	ib_send_cm_dreq(target->cm_id, NULL, 0);
+	wait_for_completion(&target->done);
+}
+
+static void srp_remove_work(void *target_ptr)
+{
+	struct srp_target_port *target = target_ptr;
+
+	spin_lock_irq(target->scsi_host->host_lock);
+	if (target->state != SRP_TARGET_DEAD) {
+		spin_unlock_irq(target->scsi_host->host_lock);
+		scsi_host_put(target->scsi_host);
+		return;
+	}
+	target->state = SRP_TARGET_REMOVED;
+	spin_unlock_irq(target->scsi_host->host_lock);
+
+	down(&target->srp_host->target_mutex);
+	list_del(&target->list);
+	up(&target->srp_host->target_mutex);
+
+	scsi_remove_host(target->scsi_host);
+	ib_destroy_cm_id(target->cm_id);
+	srp_free_target_ib(target);
+	scsi_host_put(target->scsi_host);
+	/* And another put to really free the target port... */
+	scsi_host_put(target->scsi_host);
+}
+
+static int srp_connect_target(struct srp_target_port *target)
+{
+	int ret;
+
+	ret = srp_lookup_path(target);
+	if (ret)
+		return ret;
+
+	while (1) {
+		init_completion(&target->done);
+		ret = srp_send_req(target);
+		if (ret)
+			return ret;
+		wait_for_completion(&target->done);
+
+		/*
+		 * The CM event handling code will set status to
+		 * SRP_PORT_REDIRECT if we get a port redirect REJ
+		 * back, or SRP_DLID_REDIRECT if we get a lid/qp
+		 * redirect REJ back.
+		 */
+		switch (target->status) {
+		case 0:
+			return 0;
+
+		case SRP_PORT_REDIRECT:
+			ret = srp_lookup_path(target);
+			if (ret)
+				return ret;
+			break;
+
+		case SRP_DLID_REDIRECT:
+			break;
+
+		default:
+			return target->status;
+		}
+	}
+}
+
+static int srp_reconnect_target(struct srp_target_port *target)
+{
+	struct ib_cm_id *new_cm_id;
+	struct ib_qp_attr qp_attr;
+	struct srp_request *req;
+	struct ib_wc wc;
+	int ret;
+	int i;
+
+	spin_lock_irq(target->scsi_host->host_lock);
+	if (target->state != SRP_TARGET_LIVE) {
+		spin_unlock_irq(target->scsi_host->host_lock);
+		return -EAGAIN;
+	}
+	target->state = SRP_TARGET_CONNECTING;
+	spin_unlock_irq(target->scsi_host->host_lock);
+
+	srp_disconnect_target(target);
+	/*
+	 * Now get a new local CM ID so that we avoid confusing the
+	 * target in case things are really fouled up.
+	 */
+	new_cm_id = ib_create_cm_id(target->srp_host->dev,
+				    srp_cm_handler, target);
+	if (IS_ERR(new_cm_id)) {
+		ret = PTR_ERR(new_cm_id);
+		goto err;
+	}
+	ib_destroy_cm_id(target->cm_id);
+	target->cm_id = new_cm_id;
+
+	qp_attr.qp_state = IB_QPS_RESET;
+	ret = ib_modify_qp(target->qp, &qp_attr, IB_QP_STATE);
+	if (ret)
+		goto err;
+
+	ret = srp_init_qp(target, target->qp);
+	if (ret)
+		goto err;
+
+	while (ib_poll_cq(target->cq, 1, &wc) > 0)
+		; /* nothing */
+
+	list_for_each_entry(req, &target->req_queue, list) {
+		req->scmnd->result = DID_RESET << 16;
+		req->scmnd->scsi_done(req->scmnd);
+	}
+
+	target->rx_head	 = 0;
+	target->tx_head	 = 0;
+	target->tx_tail  = 0;
+	target->req_head = 0;
+	for (i = 0; i < SRP_SQ_SIZE - 1; ++i)
+		target->req_ring[i].next = i + 1;
+	target->req_ring[SRP_SQ_SIZE - 1].next = -1;
+	INIT_LIST_HEAD(&target->req_queue);
+
+	ret = srp_connect_target(target);
+	if (ret)
+		goto err;
+
+	spin_lock_irq(target->scsi_host->host_lock);
+	if (target->state == SRP_TARGET_CONNECTING) {
+		ret = 0;
+		target->state = SRP_TARGET_LIVE;
+	} else
+		ret = -EAGAIN;
+	spin_unlock_irq(target->scsi_host->host_lock);
+
+	return ret;
+
+err:
+	printk(KERN_ERR PFX "reconnect failed (%d), removing target port.\n", ret);
+
+	/*
+	 * We couldn't reconnect, so kill our target port off.
+	 * However, we have to defer the real removal because we might
+	 * be in the context of the SCSI error handler now, which
+	 * would deadlock if we call scsi_remove_host().
+	 */
+	spin_lock_irq(target->scsi_host->host_lock);
+	if (target->state == SRP_TARGET_CONNECTING) {
+		target->state = SRP_TARGET_DEAD;
+		INIT_WORK(&target->work, srp_remove_work, target);
+		schedule_work(&target->work);
+	}
+	spin_unlock_irq(target->scsi_host->host_lock);
+
+	return ret;
+}
+
+static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
+			struct srp_request *req)
+{
+	struct srp_cmd *cmd = req->cmd->buf;
+	int len;
+	u8 fmt;
+
+	if (!scmnd->request_buffer || scmnd->sc_data_direction == DMA_NONE)
+		return sizeof (struct srp_cmd);
+
+	if (scmnd->sc_data_direction != DMA_FROM_DEVICE &&
+	    scmnd->sc_data_direction != DMA_TO_DEVICE) {
+		printk(KERN_WARNING PFX "Unhandled data direction %d\n",
+		       scmnd->sc_data_direction);
+		return -EINVAL;
+	}
+
+	if (scmnd->use_sg) {
+		struct scatterlist *scat = scmnd->request_buffer;
+		int n;
+		int i;
+
+		n = dma_map_sg(target->srp_host->dev->dma_device,
+			       scat, scmnd->use_sg, scmnd->sc_data_direction);
+
+		if (n == 1) {
+			struct srp_direct_buf *buf = (void *) cmd->add_data;
+
+			fmt = SRP_DATA_DESC_DIRECT;
+
+			buf->va  = cpu_to_be64(sg_dma_address(scat));
+			buf->key = cpu_to_be32(target->srp_host->mr->rkey);
+			buf->len = cpu_to_be32(sg_dma_len(scat));
+
+			len = sizeof (struct srp_cmd) +
+				sizeof (struct srp_direct_buf);
+		} else {
+			struct srp_indirect_buf *buf = (void *) cmd->add_data;
+			u32 datalen = 0;
+
+			fmt = SRP_DATA_DESC_INDIRECT;
+
+			if (scmnd->sc_data_direction == DMA_TO_DEVICE)
+				cmd->data_out_desc_cnt = n;
+			else
+				cmd->data_in_desc_cnt = n;
+
+			buf->table_desc.va  = cpu_to_be64(req->cmd->dma +
+							  sizeof *cmd +
+							  sizeof *buf);
+			buf->table_desc.key =
+				cpu_to_be32(target->srp_host->mr->rkey);
+			buf->table_desc.len =
+				cpu_to_be32(n * sizeof (struct srp_direct_buf));
+
+			for (i = 0; i < n; ++i) {
+				buf->desc_list[i].va  = cpu_to_be64(sg_dma_address(&scat[i]));
+				buf->desc_list[i].key =
+					cpu_to_be32(target->srp_host->mr->rkey);
+				buf->desc_list[i].len = cpu_to_be32(sg_dma_len(&scat[i]));
+
+				datalen += sg_dma_len(&scat[i]);
+			}
+
+			buf->len = cpu_to_be32(datalen);
+
+			len = sizeof (struct srp_cmd) +
+				sizeof (struct srp_indirect_buf) +
+				n * sizeof (struct srp_direct_buf);
+		}
+	} else {
+		struct srp_direct_buf *buf = (void *) cmd->add_data;
+		dma_addr_t dma;
+
+		dma = dma_map_single(target->srp_host->dev->dma_device,
+				     scmnd->request_buffer, scmnd->request_bufflen,
+				     scmnd->sc_data_direction);
+		if (dma_mapping_error(dma)) {
+			printk(KERN_WARNING PFX "unable to map %p/%d (dir %d)\n",
+			       scmnd->request_buffer, (int) scmnd->request_bufflen,
+			       scmnd->sc_data_direction);
+			return -EINVAL;
+		}
+
+		pci_unmap_addr_set(req, direct_mapping, dma);
+
+		buf->va  = cpu_to_be64(dma);
+		buf->key = cpu_to_be32(target->srp_host->mr->rkey);
+		buf->len = cpu_to_be32(scmnd->request_bufflen);
+
+		fmt = SRP_DATA_DESC_DIRECT;
+
+		len = sizeof (struct srp_cmd) + sizeof (struct srp_direct_buf);
+	}
+
+	if (scmnd->sc_data_direction == DMA_TO_DEVICE)
+		cmd->buf_fmt = fmt << 4;
+	else
+		cmd->buf_fmt = fmt;
+
+
+	return len;
+}
+
+static void srp_unmap_data(struct scsi_cmnd *scmnd,
+			   struct srp_target_port *target,
+			   struct srp_request *req)
+{
+	if (!scmnd->request_buffer ||
+	    (scmnd->sc_data_direction != DMA_TO_DEVICE &&
+	     scmnd->sc_data_direction != DMA_FROM_DEVICE))
+	    return;
+
+	if (scmnd->use_sg)
+		dma_unmap_sg(target->srp_host->dev->dma_device,
+			     (struct scatterlist *) scmnd->request_buffer,
+			     scmnd->use_sg, scmnd->sc_data_direction);
+	else
+		dma_unmap_single(target->srp_host->dev->dma_device,
+				 pci_unmap_addr(req, direct_mapping),
+				 scmnd->request_bufflen,
+				 scmnd->sc_data_direction);
+}
+
+static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
+{
+	struct srp_request *req;
+	struct scsi_cmnd *scmnd;
+	unsigned long flags;
+	s32 delta;
+
+	delta = (s32) be32_to_cpu(rsp->req_lim_delta);
+
+	spin_lock_irqsave(target->scsi_host->host_lock, flags);
+
+	target->req_lim += delta;
+
+	req = &target->req_ring[rsp->tag & ~SRP_TAG_TSK_MGMT];
+
+	if (unlikely(rsp->tag & SRP_TAG_TSK_MGMT)) {
+		if (be32_to_cpu(rsp->resp_data_len) < 4)
+			req->tsk_status = -1;
+		else
+			req->tsk_status = rsp->data[3];
+		complete(&req->done);
+	} else {
+		scmnd 	      = req->scmnd;
+		if (!scmnd)
+			printk(KERN_ERR "Null scmnd for RSP w/tag %016llx\n",
+			       (unsigned long long) rsp->tag);
+		scmnd->result = rsp->status;
+
+		if (rsp->flags & SRP_RSP_FLAG_SNSVALID) {
+			memcpy(scmnd->sense_buffer, rsp->data +
+			       be32_to_cpu(rsp->resp_data_len),
+			       min_t(int, be32_to_cpu(rsp->sense_data_len),
+				     SCSI_SENSE_BUFFERSIZE));
+		}
+
+		if (rsp->flags & (SRP_RSP_FLAG_DOOVER | SRP_RSP_FLAG_DOUNDER))
+			scmnd->resid = be32_to_cpu(rsp->data_out_res_cnt);
+		else if (rsp->flags & (SRP_RSP_FLAG_DIOVER | SRP_RSP_FLAG_DIUNDER))
+			scmnd->resid = be32_to_cpu(rsp->data_in_res_cnt);
+
+		srp_unmap_data(scmnd, target, req);
+
+		if (!req->tsk_mgmt) {
+			req->scmnd = NULL;
+			scmnd->host_scribble = (void *) -1L;
+			scmnd->scsi_done(scmnd);
+
+			list_del(&req->list);
+			req->next = target->req_head;
+			target->req_head = rsp->tag & ~SRP_TAG_TSK_MGMT;
+		} else
+			req->cmd_done = 1;
+	}
+
+	spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
+}
+
+static void srp_reconnect_work(void *target_ptr)
+{
+	struct srp_target_port *target = target_ptr;
+
+	srp_reconnect_target(target);
+}
+
+static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
+{
+	struct srp_iu *iu;
+	u8 opcode;
+
+	iu = target->rx_ring[wc->wr_id & ~SRP_OP_RECV];
+
+	dma_sync_single_for_cpu(target->srp_host->dev->dma_device, iu->dma,
+				target->max_ti_iu_len, DMA_FROM_DEVICE);
+
+	opcode = *(u8 *) iu->buf;
+
+	if (0) {
+		int i;
+
+		printk(KERN_ERR PFX "recv completion, opcode 0x%02x\n", opcode);
+
+		for (i = 0; i < wc->byte_len; ++i) {
+			if (i % 8 == 0)
+				printk(KERN_ERR "  [%02x] ", i);
+			printk(" %02x", ((u8 *) iu->buf)[i]);
+			if ((i + 1) % 8 == 0)
+				printk("\n");
+		}
+
+		if (wc->byte_len % 8)
+			printk("\n");
+	}
+
+	switch (opcode) {
+	case SRP_RSP:
+		srp_process_rsp(target, iu->buf);
+		break;
+
+	case SRP_T_LOGOUT:
+		/* XXX Handle target logout */
+		printk(KERN_WARNING PFX "Got target logout request\n");
+		break;
+
+	default:
+		printk(KERN_WARNING PFX "Unhandled SRP opcode 0x%02x\n", opcode);
+		break;
+	}
+
+	dma_sync_single_for_device(target->srp_host->dev->dma_device, iu->dma,
+				   target->max_ti_iu_len, DMA_FROM_DEVICE);
+}
+
+static void srp_completion(struct ib_cq *cq, void *target_ptr)
+{
+	struct srp_target_port *target = target_ptr;
+	struct ib_wc wc;
+	unsigned long flags;
+
+	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
+	while (ib_poll_cq(cq, 1, &wc) > 0) {
+		if (wc.status) {
+			printk(KERN_ERR PFX "failed %s status %d\n",
+			       wc.wr_id & SRP_OP_RECV ? "receive" : "send",
+			       wc.status);
+			spin_lock_irqsave(target->scsi_host->host_lock, flags);
+			if (target->state == SRP_TARGET_LIVE)
+				schedule_work(&target->work);
+			spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
+			break;
+		}
+
+		if (wc.wr_id & SRP_OP_RECV)
+			srp_handle_recv(target, &wc);
+		else
+			++target->tx_tail;
+	}
+}
+
+static int __srp_post_recv(struct srp_target_port *target)
+{
+	struct srp_iu *iu;
+	struct ib_sge list;
+	struct ib_recv_wr wr, *bad_wr;
+	unsigned int next;
+	int ret;
+
+	next 	 = target->rx_head & (SRP_RQ_SIZE - 1);
+	wr.wr_id = next | SRP_OP_RECV;
+	iu 	 = target->rx_ring[next];
+
+	list.addr   = iu->dma;
+	list.length = iu->size;
+	list.lkey   = target->srp_host->mr->lkey;
+
+	wr.next     = NULL;
+	wr.sg_list  = &list;
+	wr.num_sge  = 1;
+
+	ret = ib_post_recv(target->qp, &wr, &bad_wr);
+	if (!ret)
+		++target->rx_head;
+
+	return ret;
+}
+
+static int srp_post_recv(struct srp_target_port *target)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(target->scsi_host->host_lock, flags);
+	ret = __srp_post_recv(target);
+	spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
+
+	return ret;
+}
+
+/*
+ * Must be called with target->scsi_host->host_lock held to protect
+ * req_lim and tx_head.
+ */
+static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target)
+{
+	if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)
+		return NULL;
+
+	return target->tx_ring[target->tx_head & SRP_SQ_SIZE];
+}
+
+/*
+ * Must be called with target->scsi_host->host_lock held to protect
+ * req_lim and tx_head.
+ */
+static int __srp_post_send(struct srp_target_port *target,
+			   struct srp_iu *iu, int len)
+{
+	struct ib_sge list;
+	struct ib_send_wr wr, *bad_wr;
+	int ret = 0;
+
+	if (target->req_lim < 1) {
+		printk(KERN_ERR PFX "Target has req_lim %d\n", target->req_lim);
+		return -EAGAIN;
+	}
+
+	list.addr   = iu->dma;
+	list.length = len;
+	list.lkey   = target->srp_host->mr->lkey;
+
+	wr.next       = NULL;
+	wr.wr_id      = target->tx_head & SRP_SQ_SIZE;
+	wr.sg_list    = &list;
+	wr.num_sge    = 1;
+	wr.opcode     = IB_WR_SEND;
+	wr.send_flags = IB_SEND_SIGNALED;
+
+	ret = ib_post_send(target->qp, &wr, &bad_wr);
+
+	if (!ret) {
+		++target->tx_head;
+		--target->req_lim;
+	}
+
+	return ret;
+}
+
+static int srp_queuecommand(struct scsi_cmnd *scmnd,
+			    void (*done)(struct scsi_cmnd *))
+{
+	struct srp_target_port *target = host_to_target(scmnd->device->host);
+	struct srp_request *req;
+	struct srp_iu *iu;
+	struct srp_cmd *cmd;
+	long req_index;
+	int len;
+
+	if (target->state == SRP_TARGET_CONNECTING)
+		goto err;
+
+	if (target->state == SRP_TARGET_DEAD ||
+	    target->state == SRP_TARGET_REMOVED) {
+		scmnd->result = DID_BAD_TARGET << 16;
+		done(scmnd);
+		return 0;
+	}
+
+	iu = __srp_get_tx_iu(target);
+	if (!iu)
+		goto err;
+
+	dma_sync_single_for_cpu(target->srp_host->dev->dma_device, iu->dma,
+				SRP_MAX_IU_LEN, DMA_TO_DEVICE);
+
+	req_index = target->req_head;
+
+	scmnd->scsi_done     = done;
+	scmnd->result        = 0;
+	scmnd->host_scribble = (void *) req_index;
+
+	cmd = iu->buf;
+	memset(cmd, 0, sizeof *cmd);
+
+	cmd->opcode = SRP_CMD;
+	cmd->lun    = cpu_to_be64((u64) scmnd->device->lun << 48);
+	cmd->tag    = req_index;
+	memcpy(cmd->cdb, scmnd->cmnd, scmnd->cmd_len);
+
+	req = &target->req_ring[req_index];
+
+	req->scmnd    = scmnd;
+	req->cmd      = iu;
+	req->cmd_done = 0;
+	req->tsk_mgmt = NULL;
+
+	len = srp_map_data(scmnd, target, req);
+	if (len < 0) {
+		printk(KERN_ERR PFX "Failed to map data\n");
+		goto err;
+	}
+
+	if (__srp_post_recv(target)) {
+		printk(KERN_ERR PFX "Recv failed\n");
+		goto err_unmap;
+	}
+
+	dma_sync_single_for_device(target->srp_host->dev->dma_device, iu->dma,
+				   SRP_MAX_IU_LEN, DMA_TO_DEVICE);
+
+	if (__srp_post_send(target, iu, len)) {
+		printk(KERN_ERR PFX "Send failed\n");
+		goto err_unmap;
+	}
+
+	target->req_head = req->next;
+	list_add_tail(&req->list, &target->req_queue);
+
+	return 0;
+
+err_unmap:
+	srp_unmap_data(scmnd, target, req);
+
+err:
+	return SCSI_MLQUEUE_HOST_BUSY;
+}
+
+static int srp_alloc_iu_bufs(struct srp_target_port *target)
+{
+	int i;
+
+	for (i = 0; i < SRP_RQ_SIZE; ++i) {
+		target->rx_ring[i] = srp_alloc_iu(target->srp_host,
+						  target->max_ti_iu_len,
+						  GFP_KERNEL, DMA_FROM_DEVICE);
+		if (!target->rx_ring[i])
+			goto err;
+	}
+
+	for (i = 0; i < SRP_SQ_SIZE + 1; ++i) {
+		target->tx_ring[i] = srp_alloc_iu(target->srp_host,
+						  SRP_MAX_IU_LEN,
+						  GFP_KERNEL, DMA_TO_DEVICE);
+		if (!target->tx_ring[i])
+			goto err;
+	}
+
+	return 0;
+
+err:
+	for (i = 0; i < SRP_RQ_SIZE; ++i) {
+		srp_free_iu(target->srp_host, target->rx_ring[i]);
+		target->rx_ring[i] = NULL;
+	}
+
+	for (i = 0; i < SRP_SQ_SIZE + 1; ++i) {
+		srp_free_iu(target->srp_host, target->tx_ring[i]);
+		target->tx_ring[i] = NULL;
+	}
+
+	return -ENOMEM;
+}
+
+static void srp_cm_rej_handler(struct ib_cm_id *cm_id,
+			       struct ib_cm_event *event,
+			       struct srp_target_port *target)
+{
+	struct ib_class_port_info *cpi;
+	int opcode;
+
+	switch (event->param.rej_rcvd.reason) {
+	case IB_CM_REJ_PORT_CM_REDIRECT:
+		cpi = event->param.rej_rcvd.ari;
+		target->path.dlid = cpi->redirect_lid;
+		target->path.pkey = cpi->redirect_pkey;
+		cm_id->remote_cm_qpn = be32_to_cpu(cpi->redirect_qp) & 0x00ffffff;
+		memcpy(target->path.dgid.raw, cpi->redirect_gid, 16);
+
+		target->status = target->path.dlid ?
+			SRP_DLID_REDIRECT : SRP_PORT_REDIRECT;
+		break;
+
+	case IB_CM_REJ_PORT_REDIRECT:
+		if (topspin_workarounds &&
+		    !memcmp(&target->ioc_guid, topspin_oui, 3)) {
+			/*
+			 * Topspin/Cisco SRP gateways incorrectly send
+			 * reject reason code 25 when they mean 24
+			 * (port redirect).
+			 */
+			memcpy(target->path.dgid.raw,
+			       event->param.rej_rcvd.ari, 16);
+
+			printk(KERN_DEBUG PFX "Topspin/Cisco redirect to target port GID %016llx%016llx\n",
+			       (unsigned long long) be64_to_cpu(target->path.dgid.global.subnet_prefix),
+			       (unsigned long long) be64_to_cpu(target->path.dgid.global.interface_id));
+
+			target->status = SRP_PORT_REDIRECT;
+		} else {
+			printk(KERN_WARNING "  REJ reason: IB_CM_REJ_PORT_REDIRECT\n");
+			target->status = -ECONNRESET;
+		}
+		break;
+
+	case IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID:
+		printk(KERN_WARNING "  REJ reason: IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID\n");
+		target->status = -ECONNRESET;
+		break;
+
+	case IB_CM_REJ_CONSUMER_DEFINED:
+		opcode = *(u8 *) event->private_data;
+		if (opcode == SRP_LOGIN_REJ) {
+			struct srp_login_rej *rej = event->private_data;
+			u32 reason = be32_to_cpu(rej->reason);
+
+			if (reason == SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE)
+				printk(KERN_WARNING PFX
+				       "SRP_LOGIN_REJ: requested max_it_iu_len too large\n");
+			else
+				printk(KERN_WARNING PFX
+				       "SRP LOGIN REJECTED, reason 0x%08x\n", reason);
+		} else
+			printk(KERN_WARNING "  REJ reason: IB_CM_REJ_CONSUMER_DEFINED,"
+			       " opcode 0x%02x\n", opcode);
+		target->status = -ECONNRESET;
+		break;
+
+	default:
+		printk(KERN_WARNING "  REJ reason 0x%x\n",
+		       event->param.rej_rcvd.reason);
+		target->status = -ECONNRESET;
+	}
+}
+
+static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
+{
+	struct srp_target_port *target = cm_id->context;
+	struct ib_qp_attr *qp_attr = NULL;
+	int attr_mask = 0;
+	int comp = 0;
+	int opcode = 0;
+
+	switch (event->event) {
+	case IB_CM_REQ_ERROR:
+		printk(KERN_DEBUG PFX "Sending CM REQ failed\n");
+		comp = 1;
+		target->status = -ECONNRESET;
+		break;
+
+	case IB_CM_REP_RECEIVED:
+		comp = 1;
+		opcode = *(u8 *) event->private_data;
+
+		if (opcode == SRP_LOGIN_RSP) {
+			struct srp_login_rsp *rsp = event->private_data;
+
+			target->max_ti_iu_len = be32_to_cpu(rsp->max_ti_iu_len);
+			target->req_lim       = be32_to_cpu(rsp->req_lim_delta);
+
+			target->scsi_host->can_queue = min(target->req_lim,
+							   target->scsi_host->can_queue);
+		} else {
+			printk(KERN_WARNING PFX "Unhandled RSP opcode %#x\n", opcode);
+			target->status = -ECONNRESET;
+			break;
+		}
+
+		target->status = srp_alloc_iu_bufs(target);
+		if (target->status)
+			break;
+
+		qp_attr = kmalloc(sizeof *qp_attr, GFP_KERNEL);
+		if (!qp_attr) {
+			target->status = -ENOMEM;
+			break;
+		}
+
+		qp_attr->qp_state = IB_QPS_RTR;
+		target->status = ib_cm_init_qp_attr(cm_id, qp_attr, &attr_mask);
+		if (target->status)
+			break;
+
+		target->status = ib_modify_qp(target->qp, qp_attr, attr_mask);
+		if (target->status)
+			break;
+
+		target->status = srp_post_recv(target);
+		if (target->status)
+			break;
+
+		qp_attr->qp_state = IB_QPS_RTS;
+		target->status = ib_cm_init_qp_attr(cm_id, qp_attr, &attr_mask);
+		if (target->status)
+			break;
+
+		target->status = ib_modify_qp(target->qp, qp_attr, attr_mask);
+		if (target->status)
+			break;
+
+		target->status = ib_send_cm_rtu(cm_id, NULL, 0);
+		if (target->status)
+			break;
+
+		break;
+
+	case IB_CM_REJ_RECEIVED:
+		printk(KERN_DEBUG PFX "REJ received\n");
+		comp = 1;
+
+		srp_cm_rej_handler(cm_id, event, target);
+		break;
+
+	case IB_CM_MRA_RECEIVED:
+		printk(KERN_ERR PFX "MRA received\n");
+		break;
+
+	case IB_CM_DREP_RECEIVED:
+		break;
+
+	case IB_CM_TIMEWAIT_EXIT:
+		printk(KERN_ERR PFX "connection closed\n");
+
+		comp = 1;
+		target->status = 0;
+		break;
+
+	default:
+		printk(KERN_WARNING PFX "Unhandled CM event %d\n", event->event);
+		break;
+	}
+
+	if (comp)
+		complete(&target->done);
+
+	kfree(qp_attr);
+
+	return 0;
+}
+
+static int srp_send_tsk_mgmt(struct scsi_cmnd *scmnd, u8 func)
+{
+	struct srp_target_port *target = host_to_target(scmnd->device->host);
+	struct srp_request *req;
+	struct srp_iu *iu;
+	struct srp_tsk_mgmt *tsk_mgmt;
+	int req_index;
+	int ret = FAILED;
+
+	spin_lock_irq(target->scsi_host->host_lock);
+
+	if (scmnd->host_scribble == (void *) -1L)
+		goto out;
+
+	req_index = (long) scmnd->host_scribble;
+	printk(KERN_ERR "Abort for req_index %d\n", req_index);
+
+	req = &target->req_ring[req_index];
+	init_completion(&req->done);
+
+	iu = __srp_get_tx_iu(target);
+	if (!iu)
+		goto out;
+
+	tsk_mgmt = iu->buf;
+	memset(tsk_mgmt, 0, sizeof *tsk_mgmt);
+
+	tsk_mgmt->opcode 	= SRP_TSK_MGMT;
+	tsk_mgmt->lun 		= cpu_to_be64((u64) scmnd->device->lun << 48);
+	tsk_mgmt->tag 		= req_index | SRP_TAG_TSK_MGMT;
+	tsk_mgmt->tsk_mgmt_func = func;
+	tsk_mgmt->task_tag 	= req_index;
+
+	if (__srp_post_send(target, iu, sizeof *tsk_mgmt))
+		goto out;
+
+	req->tsk_mgmt = iu;
+
+	spin_unlock_irq(target->scsi_host->host_lock);
+	if (!wait_for_completion_timeout(&req->done,
+					 msecs_to_jiffies(SRP_ABORT_TIMEOUT_MS)))
+		return FAILED;
+	spin_lock_irq(target->scsi_host->host_lock);
+
+	if (req->cmd_done) {
+		list_del(&req->list);
+		req->next = target->req_head;
+		target->req_head = req_index;
+
+		scmnd->scsi_done(scmnd);
+	} else if (!req->tsk_status) {
+		scmnd->result = DID_ABORT << 16;
+		ret = SUCCESS;
+	}
+
+out:
+	spin_unlock_irq(target->scsi_host->host_lock);
+	return ret;
+}
+
+static int srp_abort(struct scsi_cmnd *scmnd)
+{
+	printk(KERN_ERR "SRP abort called\n");
+
+	return srp_send_tsk_mgmt(scmnd, SRP_TSK_ABORT_TASK);
+}
+
+static int srp_reset_device(struct scsi_cmnd *scmnd)
+{
+	printk(KERN_ERR "SRP reset_device called\n");
+
+	return srp_send_tsk_mgmt(scmnd, SRP_TSK_LUN_RESET);
+}
+
+static int srp_reset_host(struct scsi_cmnd *scmnd)
+{
+	struct srp_target_port *target = host_to_target(scmnd->device->host);
+	int ret = FAILED;
+
+	printk(KERN_ERR PFX "SRP reset_host called\n");
+
+	if (!srp_reconnect_target(target))
+		ret = SUCCESS;
+
+	return ret;
+}
+
+static struct scsi_host_template srp_template = {
+	.module				= THIS_MODULE,
+	.name				= DRV_NAME,
+	.info				= srp_target_info,
+	.queuecommand			= srp_queuecommand,
+	.eh_abort_handler		= srp_abort,
+	.eh_device_reset_handler	= srp_reset_device,
+	.eh_host_reset_handler		= srp_reset_host,
+	.can_queue			= SRP_SQ_SIZE,
+	.this_id			= -1,
+	.sg_tablesize			= SRP_MAX_INDIRECT,
+	.cmd_per_lun			= SRP_SQ_SIZE,
+	.use_clustering			= ENABLE_CLUSTERING
+};
+
+static int srp_add_target(struct srp_host *host, struct srp_target_port *target)
+{
+	sprintf(target->target_name, "SRP.T10:%016llX",
+		 (unsigned long long) be64_to_cpu(target->id_ext));
+
+	if (scsi_add_host(target->scsi_host, host->dev->dma_device))
+		return -ENODEV;
+
+	down(&host->target_mutex);
+	list_add_tail(&target->list, &host->target_list);
+	up(&host->target_mutex);
+
+	target->state = SRP_TARGET_LIVE;
+
+	/* XXX: are we supposed to have a definition of SCAN_WILD_CARD ?? */
+	scsi_scan_target(&target->scsi_host->shost_gendev,
+			 0, target->scsi_id, ~0, 0);
+
+	return 0;
+}
+
+static void srp_release_class_dev(struct class_device *class_dev)
+{
+	struct srp_host *host =
+		container_of(class_dev, struct srp_host, class_dev);
+
+	complete(&host->released);
+}
+
+static struct class srp_class = {
+	.name    = "infiniband_srp",
+	.release = srp_release_class_dev
+};
+
+/*
+ * Target ports are added by writing
+ *
+ *     id_ext=<SRP ID ext>,ioc_guid=<SRP IOC GUID>,dgid=<dest GID>,
+ *     pkey=<P_Key>,service_id=<service ID>
+ *
+ * to the add_target sysfs attribute.
+ */
+enum {
+	SRP_OPT_ERR		= 0,
+	SRP_OPT_ID_EXT		= 1 << 0,
+	SRP_OPT_IOC_GUID	= 1 << 1,
+	SRP_OPT_DGID		= 1 << 2,
+	SRP_OPT_PKEY		= 1 << 3,
+	SRP_OPT_SERVICE_ID	= 1 << 4,
+	SRP_OPT_MAX_SECT	= 1 << 5,
+	SRP_OPT_ALL		= (SRP_OPT_ID_EXT	|
+				   SRP_OPT_IOC_GUID	|
+				   SRP_OPT_DGID		|
+				   SRP_OPT_PKEY		|
+				   SRP_OPT_SERVICE_ID),
+};
+
+static match_table_t srp_opt_tokens = {
+	{ SRP_OPT_ID_EXT,	"id_ext=%s" 	},
+	{ SRP_OPT_IOC_GUID,	"ioc_guid=%s" 	},
+	{ SRP_OPT_DGID,		"dgid=%s" 	},
+	{ SRP_OPT_PKEY,		"pkey=%x" 	},
+	{ SRP_OPT_SERVICE_ID,	"service_id=%s" },
+	{ SRP_OPT_MAX_SECT,     "max_sect=%d" 	},
+	{ SRP_OPT_ERR,		NULL 		}
+};
+
+static int srp_parse_options(const char *buf, struct srp_target_port *target)
+{
+	char *options, *sep_opt;
+	char *p;
+	char dgid[3];
+	substring_t args[MAX_OPT_ARGS];
+	int opt_mask = 0;
+	int token;
+	int ret = -EINVAL;
+	int i;
+
+	options = kstrdup(buf, GFP_KERNEL);
+	if (!options)
+		return -ENOMEM;
+
+	sep_opt = options;
+	while ((p = strsep(&sep_opt, ",")) != NULL) {
+		if (!*p)
+			continue;
+
+		token = match_token(p, srp_opt_tokens, args);
+		opt_mask |= token;
+
+		switch (token) {
+		case SRP_OPT_ID_EXT:
+			p = match_strdup(args);
+			target->id_ext = cpu_to_be64(simple_strtoull(p, NULL, 16));
+			kfree(p);
+			break;
+
+		case SRP_OPT_IOC_GUID:
+			p = match_strdup(args);
+			target->ioc_guid = cpu_to_be64(simple_strtoull(p, NULL, 16));
+			kfree(p);
+			break;
+
+		case SRP_OPT_DGID:
+			p = match_strdup(args);
+			if (strlen(p) != 32) {
+				printk(KERN_WARNING PFX "bad dest GID parameter '%s'\n", p);
+				goto out;
+			}
+
+			for (i = 0; i < 16; ++i) {
+				strlcpy(dgid, p + i * 2, 3);
+				target->path.dgid.raw[i] = simple_strtoul(dgid, NULL, 16);
+			}
+			break;
+
+		case SRP_OPT_PKEY:
+			if (match_hex(args, &token)) {
+				printk(KERN_WARNING PFX "bad P_Key parameter '%s'\n", p);
+				goto out;
+			}
+			target->path.pkey = cpu_to_be16(token);
+			break;
+
+		case SRP_OPT_SERVICE_ID:
+			p = match_strdup(args);
+			target->service_id = cpu_to_be64(simple_strtoull(p, NULL, 16));
+			kfree(p);
+			break;
+
+		case SRP_OPT_MAX_SECT:
+			if (match_int(args, &token)) {
+				printk(KERN_WARNING PFX "bad max sect parameter '%s'\n", p);
+				goto out;
+			}
+			target->scsi_host->max_sectors = token;
+			break;
+
+		default:
+			printk(KERN_WARNING PFX "unknown parameter or missing value "
+			       "'%s' in target creation request\n", p);
+			goto out;
+		}
+	}
+
+	if ((opt_mask & SRP_OPT_ALL) == SRP_OPT_ALL)
+		ret = 0;
+	else
+		for (i = 0; i < ARRAY_SIZE(srp_opt_tokens); ++i)
+			if ((srp_opt_tokens[i].token & SRP_OPT_ALL) &&
+			    !(srp_opt_tokens[i].token & opt_mask))
+				printk(KERN_WARNING PFX "target creation request is "
+				       "missing parameter '%s'\n",
+				       srp_opt_tokens[i].pattern);
+
+out:
+	kfree(options);
+	return ret;
+}
+
+static ssize_t srp_create_target(struct class_device *class_dev,
+				 const char *buf, size_t count)
+{
+	struct srp_host *host =
+		container_of(class_dev, struct srp_host, class_dev);
+	struct Scsi_Host *target_host;
+	struct srp_target_port *target;
+	int ret;
+	int i;
+
+	target_host = scsi_host_alloc(&srp_template,
+				      sizeof (struct srp_target_port));
+	if (!target_host)
+		return -ENOMEM;
+
+	target = host_to_target(target_host);
+	memset(target, 0, sizeof *target);
+
+	target->scsi_host  = target_host;
+	target->srp_host   = host;
+
+	INIT_WORK(&target->work, srp_reconnect_work, target);
+
+	for (i = 0; i < SRP_SQ_SIZE - 1; ++i)
+		target->req_ring[i].next = i + 1;
+	target->req_ring[SRP_SQ_SIZE - 1].next = -1;
+	INIT_LIST_HEAD(&target->req_queue);
+
+	ret = srp_parse_options(buf, target);
+	if (ret)
+		goto err;
+
+	ib_get_cached_gid(host->dev, host->port, 0, &target->path.sgid);
+
+	printk(KERN_DEBUG PFX "new target: id_ext %016llx ioc_guid %016llx pkey %04x "
+	       "service_id %016llx dgid %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
+	       (unsigned long long) be64_to_cpu(target->id_ext),
+	       (unsigned long long) be64_to_cpu(target->ioc_guid),
+	       be16_to_cpu(target->path.pkey),
+	       (unsigned long long) be64_to_cpu(target->service_id),
+	       (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[0]),
+	       (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[2]),
+	       (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[4]),
+	       (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[6]),
+	       (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[8]),
+	       (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[10]),
+	       (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[12]),
+	       (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[14]));
+
+	ret = srp_create_target_ib(target);
+	if (ret)
+		goto err;
+
+	target->cm_id = ib_create_cm_id(host->dev, srp_cm_handler, target);
+	if (IS_ERR(target->cm_id)) {
+		ret = PTR_ERR(target->cm_id);
+		goto err_free;
+	}
+
+	ret = srp_connect_target(target);
+	if (ret) {
+		printk(KERN_ERR PFX "Connection failed\n");
+		goto err_cm_id;
+	}
+
+	ret = srp_add_target(host, target);
+	if (ret)
+		goto err_disconnect;
+
+	return count;
+
+err_disconnect:
+	srp_disconnect_target(target);
+
+err_cm_id:
+	ib_destroy_cm_id(target->cm_id);
+
+err_free:
+	srp_free_target_ib(target);
+
+err:
+	scsi_host_put(target_host);
+
+	return ret;
+}
+
+static CLASS_DEVICE_ATTR(add_target, S_IWUSR, NULL, srp_create_target);
+
+static ssize_t show_ibdev(struct class_device *class_dev, char *buf)
+{
+	struct srp_host *host =
+		container_of(class_dev, struct srp_host, class_dev);
+
+	return sprintf(buf, "%s\n", host->dev->name);
+}
+
+static CLASS_DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);
+
+static ssize_t show_port(struct class_device *class_dev, char *buf)
+{
+	struct srp_host *host =
+		container_of(class_dev, struct srp_host, class_dev);
+
+	return sprintf(buf, "%d\n", host->port);
+}
+
+static CLASS_DEVICE_ATTR(port, S_IRUGO, show_port, NULL);
+
+static struct srp_host *srp_add_port(struct ib_device *device,
+				     __be64 node_guid, u8 port)
+{
+	struct srp_host *host;
+
+	host = kzalloc(sizeof *host, GFP_KERNEL);
+	if (!host)
+		return NULL;
+
+	INIT_LIST_HEAD(&host->target_list);
+	init_MUTEX(&host->target_mutex);
+	init_completion(&host->released);
+	host->dev  = device;
+	host->port = port;
+
+	host->initiator_port_id[7] = port;
+	memcpy(host->initiator_port_id + 8, &node_guid, 8);
+
+	host->pd   = ib_alloc_pd(device);
+	if (IS_ERR(host->pd))
+		goto err_free;
+
+	host->mr   = ib_get_dma_mr(host->pd,
+				   IB_ACCESS_LOCAL_WRITE |
+				   IB_ACCESS_REMOTE_READ |
+				   IB_ACCESS_REMOTE_WRITE);
+	if (IS_ERR(host->mr))
+		goto err_pd;
+
+	host->class_dev.class = &srp_class;
+	host->class_dev.dev   = device->dma_device;
+	snprintf(host->class_dev.class_id, BUS_ID_SIZE, "srp-%s-%d",
+		 device->name, port);
+
+	if (class_device_register(&host->class_dev))
+		goto err_mr;
+	if (class_device_create_file(&host->class_dev, &class_device_attr_add_target))
+		goto err_class;
+	if (class_device_create_file(&host->class_dev, &class_device_attr_ibdev))
+		goto err_class;
+	if (class_device_create_file(&host->class_dev, &class_device_attr_port))
+		goto err_class;
+
+	return host;
+
+err_class:
+	class_device_unregister(&host->class_dev);
+
+err_mr:
+	ib_dereg_mr(host->mr);
+
+err_pd:
+	ib_dealloc_pd(host->pd);
+
+err_free:
+	kfree(host);
+
+	return NULL;
+}
+
+static void srp_add_one(struct ib_device *device)
+{
+	struct list_head *dev_list;
+	struct srp_host *host;
+	struct ib_device_attr *dev_attr;
+	int s, e, p;
+
+	dev_attr = kmalloc(sizeof *dev_attr, GFP_KERNEL);
+	if (!dev_attr)
+		return;
+
+	if (ib_query_device(device, dev_attr)) {
+		printk(KERN_WARNING PFX "Couldn't query node GUID for %s.\n",
+		       device->name);
+		goto out;
+	}
+
+	dev_list = kmalloc(sizeof *dev_list, GFP_KERNEL);
+	if (!dev_list)
+		goto out;
+
+	INIT_LIST_HEAD(dev_list);
+
+	if (device->node_type == IB_NODE_SWITCH) {
+		s = 0;
+		e = 0;
+	} else {
+		s = 1;
+		e = device->phys_port_cnt;
+	}
+
+	for (p = s; p <= e; ++p) {
+		host = srp_add_port(device, dev_attr->node_guid, p);
+		if (host)
+			list_add_tail(&host->list, dev_list);
+	}
+
+	ib_set_client_data(device, &srp_client, dev_list);
+
+out:
+	kfree(dev_attr);
+}
+
+static void srp_remove_one(struct ib_device *device)
+{
+	struct list_head *dev_list;
+	struct srp_host *host, *tmp_host;
+	LIST_HEAD(target_list);
+	struct srp_target_port *target, *tmp_target;
+	unsigned long flags;
+
+	dev_list = ib_get_client_data(device, &srp_client);
+
+	list_for_each_entry_safe(host, tmp_host, dev_list, list) {
+		class_device_unregister(&host->class_dev);
+		/*
+		 * Wait for the sysfs entry to go away, so that no new
+		 * target ports can be created.
+		 */
+		wait_for_completion(&host->released);
+
+		/*
+		 * Mark all target ports as removed, so we stop queueing
+		 * commands and don't try to reconnect.
+		 */
+		down(&host->target_mutex);
+		list_for_each_entry_safe(target, tmp_target,
+					 &host->target_list, list) {
+			spin_lock_irqsave(target->scsi_host->host_lock, flags);
+			if (target->state != SRP_TARGET_REMOVED)
+				target->state = SRP_TARGET_REMOVED;
+			spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
+		}
+		up(&host->target_mutex);
+
+		/*
+		 * Wait for any reconnection tasks that may have
+		 * started before we marked our target ports as
+		 * removed, and any target port removal tasks.
+		 */
+		flush_scheduled_work();
+
+		list_for_each_entry_safe(target, tmp_target,
+					 &host->target_list, list) {
+			scsi_remove_host(target->scsi_host);
+			srp_disconnect_target(target);
+			ib_destroy_cm_id(target->cm_id);
+			srp_free_target_ib(target);
+			scsi_host_put(target->scsi_host);
+		}
+
+		ib_dereg_mr(host->mr);
+		ib_dealloc_pd(host->pd);
+		kfree(host);
+	}
+
+	kfree(dev_list);
+}
+
+static int __init srp_init_module(void)
+{
+	int ret;
+
+	ret = class_register(&srp_class);
+	if (ret) {
+		printk(KERN_ERR PFX "couldn't register class infiniband_srp\n");
+		return ret;
+	}
+
+	ret = ib_register_client(&srp_client);
+	if (ret) {
+		printk(KERN_ERR PFX "couldn't register IB client\n");
+		class_unregister(&srp_class);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit srp_cleanup_module(void)
+{
+	ib_unregister_client(&srp_client);
+	class_unregister(&srp_class);
+}
+
+module_init(srp_init_module);
+module_exit(srp_cleanup_module);

drivers/infiniband/ulp/srp/ib_srp.h

···
+/*
+ * Copyright (c) 2005 Cisco Systems.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * $Id: ib_srp.h 3932 2005-11-01 17:19:29Z roland $
+ */
+
+#ifndef IB_SRP_H
+#define IB_SRP_H
+
+#include <linux/types.h>
+#include <linux/list.h>
+
+#include <asm/semaphore.h>
+
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_cmnd.h>
+
+#include <rdma/ib_verbs.h>
+#include <rdma/ib_sa.h>
+#include <rdma/ib_cm.h>
+
+enum {
+	SRP_PATH_REC_TIMEOUT_MS	= 1000,
+	SRP_ABORT_TIMEOUT_MS	= 5000,
+
+	SRP_PORT_REDIRECT	= 1,
+	SRP_DLID_REDIRECT	= 2,
+
+	SRP_MAX_IU_LEN		= 256,
+
+	SRP_RQ_SHIFT    	= 6,
+	SRP_RQ_SIZE		= 1 << SRP_RQ_SHIFT,
+	SRP_SQ_SIZE		= SRP_RQ_SIZE - 1,
+	SRP_CQ_SIZE		= SRP_SQ_SIZE + SRP_RQ_SIZE,
+
+	SRP_TAG_TSK_MGMT	= 1 << (SRP_RQ_SHIFT + 1)
+};
+
+#define SRP_OP_RECV		(1 << 31)
+#define SRP_MAX_INDIRECT	((SRP_MAX_IU_LEN -			\
+				  sizeof (struct srp_cmd) -		\
+				  sizeof (struct srp_indirect_buf)) / 16)
+
+enum srp_target_state {
+	SRP_TARGET_LIVE,
+	SRP_TARGET_CONNECTING,
+	SRP_TARGET_DEAD,
+	SRP_TARGET_REMOVED
+};
+
+struct srp_host {
+	u8			initiator_port_id[16];
+	struct ib_device       *dev;
+	u8                      port;
+	struct ib_pd	       *pd;
+	struct ib_mr	       *mr;
+	struct class_device	class_dev;
+	struct list_head	target_list;
+	struct semaphore        target_mutex;
+	struct completion	released;
+	struct list_head	list;
+};
+
+struct srp_request {
+	struct list_head	list;
+	struct scsi_cmnd       *scmnd;
+	struct srp_iu	       *cmd;
+	struct srp_iu	       *tsk_mgmt;
+	DECLARE_PCI_UNMAP_ADDR(direct_mapping)
+	struct completion	done;
+	short			next;
+	u8			cmd_done;
+	u8			tsk_status;
+};
+
+struct srp_target_port {
+	__be64			id_ext;
+	__be64			ioc_guid;
+	__be64			service_id;
+	struct srp_host	       *srp_host;
+	struct Scsi_Host       *scsi_host;
+	char			target_name[32];
+	unsigned int		scsi_id;
+
+	struct ib_sa_path_rec	path;
+	struct ib_sa_query     *path_query;
+	int			path_query_id;
+
+	struct ib_cm_id	       *cm_id;
+	struct ib_cq	       *cq;
+	struct ib_qp	       *qp;
+
+	int			max_ti_iu_len;
+	s32			req_lim;
+
+	unsigned		rx_head;
+	struct srp_iu	       *rx_ring[SRP_RQ_SIZE];
+
+	unsigned		tx_head;
+	unsigned		tx_tail;
+	struct srp_iu	       *tx_ring[SRP_SQ_SIZE + 1];
+
+	int			req_head;
+	struct list_head	req_queue;
+	struct srp_request	req_ring[SRP_SQ_SIZE];
+
+	struct work_struct	work;
+
+	struct list_head	list;
+	struct completion	done;
+	int			status;
+	enum srp_target_state	state;
+};
+
+struct srp_iu {
+	dma_addr_t		dma;
+	void		       *buf;
+	size_t			size;
+	enum dma_data_direction	direction;
+};
+
+#endif /* IB_SRP_H */

include/scsi/srp.h

···
+/*
+ * Copyright (c) 2005 Cisco Systems.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * $Id$
+ */
+
+#ifndef SCSI_SRP_H
+#define SCSI_SRP_H
+
+/*
+ * Structures and constants for the SCSI RDMA Protocol (SRP) as
+ * defined by the INCITS T10 committee.  This file was written using
+ * draft Revision 16a of the SRP standard.
+ */
+
+#include <linux/types.h>
+
+enum {
+	SRP_LOGIN_REQ	= 0x00,
+	SRP_TSK_MGMT	= 0x01,
+	SRP_CMD		= 0x02,
+	SRP_I_LOGOUT	= 0x03,
+	SRP_LOGIN_RSP	= 0xc0,
+	SRP_RSP		= 0xc1,
+	SRP_LOGIN_REJ	= 0xc2,
+	SRP_T_LOGOUT	= 0x80,
+	SRP_CRED_REQ	= 0x81,
+	SRP_AER_REQ	= 0x82,
+	SRP_CRED_RSP	= 0x41,
+	SRP_AER_RSP	= 0x42
+};
+
+enum {
+	SRP_BUF_FORMAT_DIRECT	= 1 << 1,
+	SRP_BUF_FORMAT_INDIRECT	= 1 << 2
+};
+
+enum {
+	SRP_NO_DATA_DESC	= 0,
+	SRP_DATA_DESC_DIRECT	= 1,
+	SRP_DATA_DESC_INDIRECT	= 2
+};
+
+enum {
+	SRP_TSK_ABORT_TASK	= 0x01,
+	SRP_TSK_ABORT_TASK_SET	= 0x02,
+	SRP_TSK_CLEAR_TASK_SET	= 0x04,
+	SRP_TSK_LUN_RESET	= 0x08,
+	SRP_TSK_CLEAR_ACA	= 0x40
+};
+
+enum srp_login_rej_reason {
+	SRP_LOGIN_REJ_UNABLE_ESTABLISH_CHANNEL		= 0x00010000,
+	SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES		= 0x00010001,
+	SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE	= 0x00010002,
+	SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL		= 0x00010003,
+	SRP_LOGIN_REJ_UNSUPPORTED_DESCRIPTOR_FMT	= 0x00010004,
+	SRP_LOGIN_REJ_MULTI_CHANNEL_UNSUPPORTED		= 0x00010005,
+	SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED		= 0x00010006
+};
+
+struct srp_direct_buf {
+	__be64	va;
+	__be32	key;
+	__be32  len;
+};
+
+/*
+ * We need the packed attribute because the SRP spec puts the list of
+ * descriptors at an offset of 20, which is not aligned to the size
+ * of struct srp_direct_buf.
+ */
+struct srp_indirect_buf {
+	struct srp_direct_buf	table_desc;
+	__be32			len;
+	struct srp_direct_buf	desc_list[0] __attribute__((packed));
+};
+
+enum {
+	SRP_MULTICHAN_SINGLE = 0,
+	SRP_MULTICHAN_MULTI  = 1
+};
+
+struct srp_login_req {
+	u8	opcode;
+	u8	reserved1[7];
+	u64	tag;
+	__be32	req_it_iu_len;
+	u8	reserved2[4];
+	__be16	req_buf_fmt;
+	u8	req_flags;
+	u8	reserved3[5];
+	u8	initiator_port_id[16];
+	u8	target_port_id[16];
+};
+
+struct srp_login_rsp {
+	u8	opcode;
+	u8	reserved1[3];
+	__be32	req_lim_delta;
+	u64	tag;
+	__be32	max_it_iu_len;
+	__be32	max_ti_iu_len;
+	__be16	buf_fmt;
+	u8	rsp_flags;
+	u8	reserved2[25];
+};
+
+struct srp_login_rej {
+	u8	opcode;
+	u8	reserved1[3];
+	__be32	reason;
+	u64	tag;
+	u8	reserved2[8];
+	__be16	buf_fmt;
+	u8	reserved3[6];
+};
+
+struct srp_i_logout {
+	u8	opcode;
+	u8	reserved[7];
+	u64	tag;
+};
+
+struct srp_t_logout {
+	u8	opcode;
+	u8	sol_not;
+	u8	reserved[2];
+	__be32	reason;
+	u64	tag;
+};
+
+/*
+ * We need the packed attribute because the SRP spec only aligns the
+ * 8-byte LUN field to 4 bytes.
+ */
+struct srp_tsk_mgmt {
+	u8	opcode;
+	u8	sol_not;
+	u8	reserved1[6];
+	u64	tag;
+	u8	reserved2[4];
+	__be64	lun __attribute__((packed));
+	u8	reserved3[2];
+	u8	tsk_mgmt_func;
+	u8	reserved4;
+	u64	task_tag;
+	u8	reserved5[8];
+};
+
+/*
+ * We need the packed attribute because the SRP spec only aligns the
+ * 8-byte LUN field to 4 bytes.
+ */
+struct srp_cmd {
+	u8	opcode;
+	u8	sol_not;
+	u8	reserved1[3];
+	u8	buf_fmt;
+	u8	data_out_desc_cnt;
+	u8	data_in_desc_cnt;
+	u64	tag;
+	u8	reserved2[4];
+	__be64	lun __attribute__((packed));
+	u8	reserved3;
+	u8	task_attr;
+	u8	reserved4;
+	u8	add_cdb_len;
+	u8	cdb[16];
+	u8	add_data[0];
+};
+
+enum {
+	SRP_RSP_FLAG_RSPVALID = 1 << 0,
+	SRP_RSP_FLAG_SNSVALID = 1 << 1,
+	SRP_RSP_FLAG_DOOVER   = 1 << 2,
+	SRP_RSP_FLAG_DOUNDER  = 1 << 3,
+	SRP_RSP_FLAG_DIOVER   = 1 << 4,
+	SRP_RSP_FLAG_DIUNDER  = 1 << 5
+};
+
+struct srp_rsp {
+	u8	opcode;
+	u8	sol_not;
+	u8	reserved1[2];
+	__be32	req_lim_delta;
+	u64	tag;
+	u8	reserved2[2];
+	u8	flags;
+	u8	status;
+	__be32	data_out_res_cnt;
+	__be32	data_in_res_cnt;
+	__be32	sense_data_len;
+	__be32	resp_data_len;
+	u8	data[0];
+};
+
+#endif /* SCSI_SRP_H */