ib_srpt: Initial SRP Target merge for v3.3-rc1

This patch adds the kernel module ib_srpt SCSI RDMA Protocol (SRP) target
implementation conforming to the SRP r16a specification for the mainline
drivers/target infrastructure.

This driver was originally developed by Vu Pham and has been optimized by
Bart Van Assche and merged into upstream LIO based on his srpt-lio-4.1
branch here:

   https://github.com/bvanassche/srpt-lio/commits/srpt-lio-4.1/

This updated patch also contains the following two changes from
lio-core-2.6.git/master.  One is to fix a bug with 1 >= task->task_sg[]
chained mappings in ib_srpt, and the other to convert the configfs control
plane to reference IB Port GUID and struct srpt_port directly following
mainline v4.x target_core_fabric_configfs.c convertion for ib_srpt
to work with rtslib/rtsadmin v2 code.

These seperate patches can be found here:

ib_srpt: Fix bug with chainged SGLs in srpt_map_sg_to_ib_sge
http://www.risingtidesystems.com/git/?p=lio-core-2.6.git;a=commitdiff;h=ea485147563b6555a97dbf811825fbb586519252

ib_srpt: Convert se_wwn endpoint reference to struct srpt_port->port_wwn
http://www.risingtidesystems.com/git/?p=lio-core-2.6.git;a=commitdiff;h=4e544a210acb227df1bb4ca5086e65bdf4e648ea

This also includes the following recent v1 -> v2 review changes:

ib_srpt: Fix potential out-of-bounds array access
ib_srpt: Avoid failed multipart RDMA transfers
ib_srpt: Fix srpt_alloc_fabric_acl failure case return value
ib_srpt: Update comments to reference $driver/$port layout
ib_srpt: Fix sport->port_guid formatting code
ib_srpt: Remove legacy use_port_guid_in_session_name module parameter
ib_srpt: Convert srp_max_rdma_size into per port configfs attribute
ib_srpt: Convert srp_max_rsp_size into per port configfs attribute
ib_srpt: Convert srpt_sq_size into per port configfs attribute

and v2 -> v3 review changes:

ib_srpt: Fix possible race with srp_sq_size in srpt_create_ch_ib
ib_srpt: Fix possible race with srp_max_rsp_size in srpt_release_channel_work
ib_srpt: Fix up MAX_SRPT_RDMA_SIZE define
ib_srpt: Make srpt_map_sg_to_ib_sge() failure case return -EAGAIN
ib_srpt: Convert port_guid to use subnet_prefix + interface_id formatting
ib_srpt: Make srpt_check_stop_free return kref_put status
ib_srpt: Make compilation with BUG=n proceed`
ib_srpt: Use new target_core_fabric.h include
ib_srpt: Check hex2bin() return code to silence build warning

Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Vu Pham <vu@mellanox.com>
Cc: David Dillow <dillowda@ornl.gov>
Signed-off-by: Nicholas A. Bellinger <nab@risingtidesystems.com>

drivers/infiniband/Kconfig

@@ -55,6 +55,7 @@ source "drivers/infiniband/hw/nes/Kconfig"
 source "drivers/infiniband/ulp/ipoib/Kconfig"
 
 source "drivers/infiniband/ulp/srp/Kconfig"
+source "drivers/infiniband/ulp/srpt/Kconfig"
 
 source "drivers/infiniband/ulp/iser/Kconfig"
 

drivers/infiniband/Makefile

@@ -10,4 +10,5 @@ obj-$(CONFIG_MLX4_INFINIBAND)		+= hw/mlx4/
 obj-$(CONFIG_INFINIBAND_NES)		+= hw/nes/
 obj-$(CONFIG_INFINIBAND_IPOIB)		+= ulp/ipoib/
 obj-$(CONFIG_INFINIBAND_SRP)		+= ulp/srp/
+obj-$(CONFIG_INFINIBAND_SRPT)		+= ulp/srpt/
 obj-$(CONFIG_INFINIBAND_ISER)		+= ulp/iser/

drivers/infiniband/ulp/srpt/Kconfig

+config INFINIBAND_SRPT
+	tristate "InfiniBand SCSI RDMA Protocol target support"
+	depends on INFINIBAND && TARGET_CORE
+	---help---
+
+	  Support for the SCSI RDMA Protocol (SRP) Target driver. The
+	  SRP protocol is a protocol that allows an initiator to access
+	  a block storage device on another host (target) over a network
+	  that supports the RDMA protocol. Currently the RDMA protocol is
+	  supported by InfiniBand and by iWarp network hardware. More
+	  information about the SRP protocol can be found on the website
+	  of the INCITS T10 technical committee (http://www.t10.org/).

drivers/infiniband/ulp/srpt/Makefile

+ccflags-y			:= -Idrivers/target
+obj-$(CONFIG_INFINIBAND_SRPT)	+= ib_srpt.o

drivers/infiniband/ulp/srpt/ib_dm_mad.h

+/*
+ * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  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.
+ *
+ */
+
+#ifndef IB_DM_MAD_H
+#define IB_DM_MAD_H
+
+#include <linux/types.h>
+
+#include <rdma/ib_mad.h>
+
+enum {
+	/*
+	 * See also section 13.4.7 Status Field, table 115 MAD Common Status
+	 * Field Bit Values and also section 16.3.1.1 Status Field in the
+	 * InfiniBand Architecture Specification.
+	 */
+	DM_MAD_STATUS_UNSUP_METHOD = 0x0008,
+	DM_MAD_STATUS_UNSUP_METHOD_ATTR = 0x000c,
+	DM_MAD_STATUS_INVALID_FIELD = 0x001c,
+	DM_MAD_STATUS_NO_IOC = 0x0100,
+
+	/*
+	 * See also the Device Management chapter, section 16.3.3 Attributes,
+	 * table 279 Device Management Attributes in the InfiniBand
+	 * Architecture Specification.
+	 */
+	DM_ATTR_CLASS_PORT_INFO = 0x01,
+	DM_ATTR_IOU_INFO = 0x10,
+	DM_ATTR_IOC_PROFILE = 0x11,
+	DM_ATTR_SVC_ENTRIES = 0x12
+};
+
+struct ib_dm_hdr {
+	u8 reserved[28];
+};
+
+/*
+ * Structure of management datagram sent by the SRP target implementation.
+ * Contains a management datagram header, reliable multi-packet transaction
+ * protocol (RMPP) header and ib_dm_hdr. Notes:
+ * - The SRP target implementation does not use RMPP or ib_dm_hdr when sending
+ *   management datagrams.
+ * - The header size must be exactly 64 bytes (IB_MGMT_DEVICE_HDR), since this
+ *   is the header size that is passed to ib_create_send_mad() in ib_srpt.c.
+ * - The maximum supported size for a management datagram when not using RMPP
+ *   is 256 bytes -- 64 bytes header and 192 (IB_MGMT_DEVICE_DATA) bytes data.
+ */
+struct ib_dm_mad {
+	struct ib_mad_hdr mad_hdr;
+	struct ib_rmpp_hdr rmpp_hdr;
+	struct ib_dm_hdr dm_hdr;
+	u8 data[IB_MGMT_DEVICE_DATA];
+};
+
+/*
+ * IOUnitInfo as defined in section 16.3.3.3 IOUnitInfo of the InfiniBand
+ * Architecture Specification.
+ */
+struct ib_dm_iou_info {
+	__be16 change_id;
+	u8 max_controllers;
+	u8 op_rom;
+	u8 controller_list[128];
+};
+
+/*
+ * IOControllerprofile as defined in section 16.3.3.4 IOControllerProfile of
+ * the InfiniBand Architecture Specification.
+ */
+struct ib_dm_ioc_profile {
+	__be64 guid;
+	__be32 vendor_id;
+	__be32 device_id;
+	__be16 device_version;
+	__be16 reserved1;
+	__be32 subsys_vendor_id;
+	__be32 subsys_device_id;
+	__be16 io_class;
+	__be16 io_subclass;
+	__be16 protocol;
+	__be16 protocol_version;
+	__be16 service_conn;
+	__be16 initiators_supported;
+	__be16 send_queue_depth;
+	u8 reserved2;
+	u8 rdma_read_depth;
+	__be32 send_size;
+	__be32 rdma_size;
+	u8 op_cap_mask;
+	u8 svc_cap_mask;
+	u8 num_svc_entries;
+	u8 reserved3[9];
+	u8 id_string[64];
+};
+
+struct ib_dm_svc_entry {
+	u8 name[40];
+	__be64 id;
+};
+
+/*
+ * See also section 16.3.3.5 ServiceEntries in the InfiniBand Architecture
+ * Specification. See also section B.7, table B.8 in the T10 SRP r16a document.
+ */
+struct ib_dm_svc_entries {
+	struct ib_dm_svc_entry service_entries[4];
+};
+
+#endif