[SCSI] SCSI and FC Transport: add netlink support for posting of transport events

This patch formally adds support for the posting of FC events via netlink.
It is a followup to the original RFC at:
  http://marc.theaimsgroup.com/?l=linux-scsi&m=114530667923464&w=2
and the initial posting at:
  http://marc.theaimsgroup.com/?l=linux-scsi&m=115507374832500&w=2

The patch has been updated to optimize the send path, per the discussions
in the initial posting.

Per discussions at the Storage Summit and at OLS, we are to use netlink for
async events from transports. Also per discussions, to avoid a netlink
protocol per transport, I've create a single NETLINK_SCSITRANSPORT protocol,
which can then be used by all transports.

This patch:
- Creates new files scsi_netlink.c and scsi_netlink.h, which contains the
  single and shared definitions for the SCSI Transport. It is tied into the
  base SCSI subsystem intialization.
  Contains a single interface routine, scsi_send_transport_event(), for a
  transport to send an event (via multicast to a protocol specific group).
- Creates a new scsi_netlink_fc.h file, which contains the FC netlink event
  messages
- Adds 3 new routines to the fc transport:
   fc_get_event_number() -  to get a FC event #
   fc_host_post_event()  -  to send a simple FC event (32 bits of data)
   fc_host_post_vendor_event() - to send a Vendor unique event, with
                                 arbitrary amounts of data.

   Note: the separation of event number allows for a LLD to send a standard
     event, followed by vendor-specific data for the event.

Note: This patch assumes 2 prior fc transport patches have been installed:
   http://marc.theaimsgroup.com/?l=linux-scsi&m=115555807316329&w=2
   http://marc.theaimsgroup.com/?l=linux-scsi&m=115581614930261&w=2

   Sorry - next time I'll do something like making these individual
   patches of the same posting when I know they'll be posted closely
   together.

Signed-off-by: James Smart <James.Smart@emulex.com>

Tidy up configuration not to make SCSI always select NET

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

3 files changed, 191 insertions, 0 deletions

diff --git a/include/scsi/scsi_netlink.h b/include/scsi/scsi_netlink.h
new file mode 100644
index 000000000000..7a3a20e640c0
--- /dev/null
+++ b/include/scsi/scsi_netlink.h
@@ -0,0 +1,86 @@
+/*
+ *  SCSI Transport Netlink Interface
+ *    Used for the posting of outbound SCSI transport events
+ *
+ *  Copyright (C) 2006   James Smart, Emulex Corporation
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+#ifndef SCSI_NETLINK_H
+#define SCSI_NETLINK_H
+
+/*
+ * This file intended to be included by both kernel and user space
+ */
+
+/* Single Netlink Message type to send all SCSI Transport messages */
+#define SCSI_TRANSPORT_MSG              NLMSG_MIN_TYPE + 1
+
+/* SCSI Transport Broadcast Groups */
+        /* leaving groups 0 and 1 unassigned */
+#define SCSI_NL_GRP_FC_EVENTS           (1<<2)          /* Group 2 */
+#define SCSI_NL_GRP_CNT                 3
+
+
+/* SCSI_TRANSPORT_MSG event message header */
+struct scsi_nl_hdr {
+        uint8_t version;
+        uint8_t transport;
+        uint16_t magic;
+        uint16_t msgtype;
+        uint16_t msglen;
+} __attribute__((aligned(sizeof(uint64_t))));
+
+/* scsi_nl_hdr->version value */
+#define SCSI_NL_VERSION                         1
+
+/* scsi_nl_hdr->magic value */
+#define SCSI_NL_MAGIC                           0xA1B2
+
+/* scsi_nl_hdr->transport value */
+#define SCSI_NL_TRANSPORT                       0
+#define SCSI_NL_TRANSPORT_FC                    1
+#define SCSI_NL_MAX_TRANSPORTS                  2
+
+/* scsi_nl_hdr->msgtype values are defined in each transport */
+
+
+/*
+ * Vendor ID:
+ *   If transports post vendor-unique events, they must pass a well-known
+ *   32-bit vendor identifier. This identifier consists of 8 bits indicating
+ *   the "type" of identifier contained, and 24 bits of id data.
+ *
+ *   Identifiers for each type:
+ *    PCI :  ID data is the 16 bit PCI Registered Vendor ID
+ */
+#define SCSI_NL_VID_ID_MASK                     0x00FFFFFF
+#define SCSI_NL_VID_TYPE_MASK                   0xFF000000
+#define SCSI_NL_VID_TYPE_PCI                    0x01000000
+
+
+#define INIT_SCSI_NL_HDR(hdr, t, mtype, mlen)                   \
+        {                                                       \
+        (hdr)->version = SCSI_NL_VERSION;                       \
+        (hdr)->transport = t;                                   \
+        (hdr)->magic = SCSI_NL_MAGIC;                           \
+        (hdr)->msgtype = mtype;                                 \
+        (hdr)->msglen = mlen;                                   \
+        }
+
+
+#endif /* SCSI_NETLINK_H */
+
diff --git a/include/scsi/scsi_netlink_fc.h b/include/scsi/scsi_netlink_fc.h
new file mode 100644
index 000000000000..b213d2909fed
--- /dev/null
+++ b/include/scsi/scsi_netlink_fc.h
@@ -0,0 +1,71 @@
+/*
+ *  FC Transport Netlink Interface
+ *
+ *  Copyright (C) 2006   James Smart, Emulex Corporation
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+#ifndef SCSI_NETLINK_FC_H
+#define SCSI_NETLINK_FC_H
+
+#include <scsi/scsi_netlink.h>
+
+/*
+ * This file intended to be included by both kernel and user space
+ */
+
+/*
+ * FC Transport Message Types
+ */
+        /* kernel -> user */
+#define FC_NL_ASYNC_EVENT                       0x0100
+        /* user -> kernel */
+/* none */
+
+
+/*
+ * Message Structures :
+ */
+
+/* macro to round up message lengths to 8byte boundary */
+#define FC_NL_MSGALIGN(len)             (((len) + 7) & ~7)
+
+
+/*
+ * FC Transport Broadcast Event Message :
+ *   FC_NL_ASYNC_EVENT
+ *
+ * Note: if Vendor Unique message, &event_data will be  start of
+ *       vendor unique payload, and the length of the payload is
+ *       per event_datalen
+ *
+ * Note: When specifying vendor_id, be sure to read the Vendor Type and ID
+ *   formatting requirements specified in scsi_netlink.h
+ */
+struct fc_nl_event {
+        struct scsi_nl_hdr snlh;                /* must be 1st element ! */
+        uint64_t seconds;
+        uint32_t vendor_id;
+        uint16_t host_no;
+        uint16_t event_datalen;
+        uint32_t event_num;
+        uint32_t event_code;
+        uint32_t event_data;
+} __attribute__((aligned(sizeof(uint64_t))));
+
+
+#endif /* SCSI_NETLINK_FC_H */
+
diff --git a/include/scsi/scsi_transport_fc.h b/include/scsi/scsi_transport_fc.h
index c74be5dabfeb..f91c5358af3a 100644
--- a/include/scsi/scsi_transport_fc.h
+++ b/include/scsi/scsi_transport_fc.h
@@ -29,6 +29,7 @@
 
 #include <linux/sched.h>
 #include <scsi/scsi.h>
+#include <scsi/scsi_netlink.h>
 
 struct scsi_transport_template;
 
@@ -284,6 +285,30 @@ struct fc_host_statistics {
 
 
 /*
+ * FC Event Codes - Polled and Async, following FC HBAAPI v2.0 guidelines
+ */
+
+/*
+ * fc_host_event_code: If you alter this, you also need to alter
+ * scsi_transport_fc.c (for the ascii descriptions).
+ */
+enum fc_host_event_code  {
+        FCH_EVT_LIP                     = 0x1,
+        FCH_EVT_LINKUP                  = 0x2,
+        FCH_EVT_LINKDOWN                = 0x3,
+        FCH_EVT_LIPRESET                = 0x4,
+        FCH_EVT_RSCN                    = 0x5,
+        FCH_EVT_ADAPTER_CHANGE          = 0x103,
+        FCH_EVT_PORT_UNKNOWN            = 0x200,
+        FCH_EVT_PORT_OFFLINE            = 0x201,
+        FCH_EVT_PORT_ONLINE             = 0x202,
+        FCH_EVT_PORT_FABRIC             = 0x204,
+        FCH_EVT_LINK_UNKNOWN            = 0x500,
+        FCH_EVT_VENDOR_UNIQUE           = 0xffff,
+};
+
+
+/*
  * FC Local Port (Host) Attributes
  *
  * Attributes are based on HBAAPI V2.0 definitions.
@@ -526,5 +551,14 @@ struct fc_rport *fc_remote_port_add(struct Scsi_Host *shost,
 void fc_remote_port_delete(struct fc_rport  *rport);
 void fc_remote_port_rolechg(struct fc_rport  *rport, u32 roles);
 int scsi_is_fc_rport(const struct device *);
+u32 fc_get_event_number(void);
+void fc_host_post_event(struct Scsi_Host *shost, u32 event_number,
+                enum fc_host_event_code event_code, u32 event_data);
+void fc_host_post_vendor_event(struct Scsi_Host *shost, u32 event_number,
+                u32 data_len, char * data_buf, u32 vendor_id);
+        /* Note: when specifying vendor_id to fc_host_post_vendor_event()
+         *   be sure to read the Vendor Type and ID formatting requirements
+         *   specified in scsi_netlink.h
+         */
 
 #endif /* SCSI_TRANSPORT_FC_H */