[SCSI] scsi tgt: SCSI RDMA Protocol library functions

libsrp provides helper functions for SRP target drivers.

Some SRP target drivers would be out of drivers/scsi/ so we added an
entry for libsrp in drivers/scsi/Kconfig.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Santiago Leon <santil@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/Kconfig

@@ -1760,6 +1760,16 @@ config ZFCP
           called zfcp. If you want to compile it as a module, say M here
           and read <file:Documentation/modules.txt>.
 
+config SCSI_SRP
+	tristate "SCSI RDMA Protocol helper library"
+	depends on SCSI && PCI
+	select SCSI_TGT
+	help
+	  If you wish to use SRP target drivers, say Y.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called libsrp.
+
 endmenu
 
 source "drivers/scsi/pcmcia/Kconfig"

drivers/scsi/Makefile

@@ -126,6 +126,7 @@ obj-$(CONFIG_SCSI_FCAL)		+= fcal.o
 obj-$(CONFIG_SCSI_LASI700)	+= 53c700.o lasi700.o
 obj-$(CONFIG_SCSI_NSP32)	+= nsp32.o
 obj-$(CONFIG_SCSI_IPR)		+= ipr.o
+obj-$(CONFIG_SCSI_SRP)		+= libsrp.o
 obj-$(CONFIG_SCSI_IBMVSCSI)	+= ibmvscsi/
 obj-$(CONFIG_SCSI_HPTIOP)	+= hptiop.o
 obj-$(CONFIG_SCSI_STEX)		+= stex.o

include/scsi/libsrp.h

+#ifndef __LIBSRP_H__
+#define __LIBSRP_H__
+
+#include <linux/list.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_host.h>
+#include <scsi/srp.h>
+
+enum iue_flags {
+	V_DIOVER,
+	V_WRITE,
+	V_LINKED,
+	V_FLYING,
+};
+
+struct srp_buf {
+	dma_addr_t dma;
+	void *buf;
+};
+
+struct srp_queue {
+	void *pool;
+	void *items;
+	struct kfifo *queue;
+	spinlock_t lock;
+};
+
+struct srp_target {
+	struct Scsi_Host *shost;
+	struct device *dev;
+
+	spinlock_t lock;
+	struct list_head cmd_queue;
+
+	size_t srp_iu_size;
+	struct srp_queue iu_queue;
+	size_t rx_ring_size;
+	struct srp_buf **rx_ring;
+
+	void *ldata;
+};
+
+struct iu_entry {
+	struct srp_target *target;
+
+	struct list_head ilist;
+	dma_addr_t remote_token;
+	unsigned long flags;
+
+	struct srp_buf *sbuf;
+};
+
+typedef int (srp_rdma_t)(struct scsi_cmnd *, struct scatterlist *, int,
+			 struct srp_direct_buf *, int,
+			 enum dma_data_direction, unsigned int);
+extern int srp_target_alloc(struct srp_target *, struct device *, size_t, size_t);
+extern void srp_target_free(struct srp_target *);
+
+extern struct iu_entry *srp_iu_get(struct srp_target *);
+extern void srp_iu_put(struct iu_entry *);
+
+extern int srp_cmd_queue(struct Scsi_Host *, struct srp_cmd *, void *, u64);
+extern int srp_transfer_data(struct scsi_cmnd *, struct srp_cmd *,
+			     srp_rdma_t, int, int);
+
+
+static inline struct srp_target *host_to_srp_target(struct Scsi_Host *host)
+{
+	return (struct srp_target *) host->hostdata;
+}
+
+static inline int srp_cmd_direction(struct srp_cmd *cmd)
+{
+	return (cmd->buf_fmt >> 4) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
+}
+
+#endif