[SCSI] scsi_netlink: Add transport and LLD recieve and event support

This patch adds scsi netlink recieve and event support for transport
and scsi LLDD's.  It is a reimplementation of the patch posted last
week by David Somayajulu.
http://marc.info/?l=linux-scsi&m=121745486221819&w=2

There are a few things done differently:

- Transport support is included

- Event delivery is included

- The vendor message is now its own unique message type, considered
  part of the generic "SCSI Transport".

- LLDD entry points are now registered rather than included in the
  scsi_host_template.

  Background: When I started to implement the event handler via template,
  I had to either: muck up scsi_add_host and scsi_remove_host;  or have
  the event handler search all possible shosts. Neither was acceptable.
  Moving to a registration solves this, and also limits the scope of
  the changes to something that could be backported to a distro without
  breaking an already-released-distro kabi. However, I admit it isn't
  as elegant, as the passing of the LLDD host template in the
  registration and the complexity around dynamic add/remove shows.

- The receive path was augmented to require a unique identifier for
  the LLDD before the message was allowed to be handed off to the
  driver. Given how quickly very fatal errors occur if there's msg
  mismatches (which I saw in testing my own tools :), I believe this
  to be a very good thing. The id plays off the vendor id scheme already
  introduced for the vendor unique event messages used by FC.
  Additionally, the id use as the basis of the registration/deregistration.

- Send assist functions, for both the transport and LLDDs are included.

[fujita.tomonori@lab.ntt.co.jp: fix missing cast]
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 61 insertions, 1 deletions

diff --git a/include/scsi/scsi_netlink.h b/include/scsi/scsi_netlink.h
index 8c1470cc8209..536752c40d41 100644
--- a/include/scsi/scsi_netlink.h
+++ b/include/scsi/scsi_netlink.h
@@ -22,6 +22,9 @@
 #ifndef SCSI_NETLINK_H
 #define SCSI_NETLINK_H
 
+#include <linux/netlink.h>
+
+
 /*
  * This file intended to be included by both kernel and user space
  */
@@ -55,7 +58,41 @@ struct scsi_nl_hdr {
 #define SCSI_NL_TRANSPORT_FC			1
 #define SCSI_NL_MAX_TRANSPORTS			2
 
-/* scsi_nl_hdr->msgtype values are defined in each transport */
+/* Transport-based scsi_nl_hdr->msgtype values are defined in each transport */
+
+/*
+ * GENERIC SCSI scsi_nl_hdr->msgtype Values
+ */
+	/* kernel -> user */
+#define SCSI_NL_SHOST_VENDOR			0x0001
+	/* user -> kernel */
+/* SCSI_NL_SHOST_VENDOR msgtype is kernel->user and user->kernel */
+
+
+/*
+ * Message Structures :
+ */
+
+/* macro to round up message lengths to 8byte boundary */
+#define SCSI_NL_MSGALIGN(len)		(((len) + 7) & ~7)
+
+
+/*
+ * SCSI HOST Vendor Unique messages :
+ *   SCSI_NL_SHOST_VENDOR
+ *
+ * Note: The Vendor Unique message payload will begin directly after
+ * 	 this structure, with the length of the payload per vmsg_datalen.
+ *
+ * Note: When specifying vendor_id, be sure to read the Vendor Type and ID
+ *   formatting requirements specified below
+ */
+struct scsi_nl_host_vendor_msg {
+	struct scsi_nl_hdr snlh;		/* must be 1st element ! */
+	uint64_t vendor_id;
+	uint16_t host_no;
+	uint16_t vmsg_datalen;
+} __attribute__((aligned(sizeof(uint64_t))));
 
 
 /*
@@ -83,5 +120,28 @@ struct scsi_nl_hdr {
 	}
 
 
+#ifdef __KERNEL__
+
+#include <scsi/scsi_host.h>
+
+/* Exported Kernel Interfaces */
+int scsi_nl_add_transport(u8 tport,
+	 int (*msg_handler)(struct sk_buff *),
+	void (*event_handler)(struct notifier_block *, unsigned long, void *));
+void scsi_nl_remove_transport(u8 tport);
+
+int scsi_nl_add_driver(u64 vendor_id, struct scsi_host_template *hostt,
+	int (*nlmsg_handler)(struct Scsi_Host *shost, void *payload,
+				 u32 len, u32 pid),
+	void (*nlevt_handler)(struct notifier_block *nb,
+				 unsigned long event, void *notify_ptr));
+void scsi_nl_remove_driver(u64 vendor_id);
+
+void scsi_nl_send_transport_msg(u32 pid, struct scsi_nl_hdr *hdr);
+int scsi_nl_send_vendor_msg(u32 pid, unsigned short host_no, u64 vendor_id,
+			 char *data_buf, u32 data_len);
+
+#endif /* __KERNEL__ */
+
 #endif /* SCSI_NETLINK_H */