[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>

1 files changed, 77 insertions, 0 deletions

diff --git a/include/scsi/libsrp.h b/include/scsi/libsrp.h
new file mode 100644
index 000000000000..d143171896ae
--- /dev/null
+++ b/include/scsi/libsrp.h
@@ -0,0 +1,77 @@
+#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