[SCSI] scsi_transport_iscsi: added support for host event

Added support to post kernel host event to application using
netlink interface.

Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

3 files changed, 50 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 787044828a70..38f0bf8ea91a 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -1476,6 +1476,37 @@ void iscsi_conn_login_event(struct iscsi_cls_conn *conn,
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_login_event);
 
+void iscsi_post_host_event(uint32_t host_no, struct iscsi_transport *transport,
+                           enum iscsi_host_event_code code, uint32_t data_size,
+                           uint8_t *data)
+{
+        struct nlmsghdr *nlh;
+        struct sk_buff *skb;
+        struct iscsi_uevent *ev;
+        int len = NLMSG_SPACE(sizeof(*ev) + data_size);
+
+        skb = alloc_skb(len, GFP_KERNEL);
+        if (!skb) {
+                printk(KERN_ERR "gracefully ignored host event (%d):%d OOM\n",
+                       host_no, code);
+                return;
+        }
+
+        nlh = __nlmsg_put(skb, 0, 0, 0, (len - sizeof(*nlh)), 0);
+        ev = NLMSG_DATA(nlh);
+        ev->transport_handle = iscsi_handle(transport);
+        ev->type = ISCSI_KEVENT_HOST_EVENT;
+        ev->r.host_event.host_no = host_no;
+        ev->r.host_event.code = code;
+        ev->r.host_event.data_size = data_size;
+
+        if (data_size)
+                memcpy((char *)ev + sizeof(*ev), data, data_size);
+
+        iscsi_multicast_skb(skb, ISCSI_NL_GRP_ISCSID, GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(iscsi_post_host_event);
+
 static int
 iscsi_if_send_reply(uint32_t group, int seq, int type, int done, int multi,
                     void *payload, int size)
diff --git a/include/scsi/iscsi_if.h b/include/scsi/iscsi_if.h
index e49b7c8dd217..3aac99155e80 100644
--- a/include/scsi/iscsi_if.h
+++ b/include/scsi/iscsi_if.h
@@ -72,6 +72,7 @@ enum iscsi_uevent_e {
         ISCSI_KEVENT_PATH_REQ           = KEVENT_BASE + 7,
         ISCSI_KEVENT_IF_DOWN            = KEVENT_BASE + 8,
         ISCSI_KEVENT_CONN_LOGIN_STATE   = KEVENT_BASE + 9,
+        ISCSI_KEVENT_HOST_EVENT         = KEVENT_BASE + 10,
 };
 
 enum iscsi_tgt_dscvr {
@@ -80,6 +81,13 @@ enum iscsi_tgt_dscvr {
         ISCSI_TGT_DSCVR_SLP             = 3,
 };
 
+enum iscsi_host_event_code {
+        ISCSI_EVENT_LINKUP              = 1,
+        ISCSI_EVENT_LINKDOWN,
+        /* must always be last */
+        ISCSI_EVENT_MAX,
+};
+
 struct iscsi_uevent {
         uint32_t type; /* k/u events type */
         uint32_t iferror; /* carries interface or resource errors */
@@ -222,6 +230,11 @@ struct iscsi_uevent {
                 struct msg_notify_if_down {
                         uint32_t        host_no;
                 } notify_if_down;
+                struct msg_host_event {
+                        uint32_t        host_no;
+                        uint32_t        data_size;
+                        enum iscsi_host_event_code code;
+                } host_event;
         } r;
 } __attribute__ ((aligned (sizeof(uint64_t))));
 
diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
index fa7ca4e16020..7f047314281b 100644
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -166,6 +166,12 @@ extern int iscsi_offload_mesg(struct Scsi_Host *shost,
                               struct iscsi_transport *transport, uint32_t type,
                               char *data, uint16_t data_size);
 
+extern void iscsi_post_host_event(uint32_t host_no,
+                                  struct iscsi_transport *transport,
+                                  enum iscsi_host_event_code code,
+                                  uint32_t data_size,
+                                  uint8_t *data);
+
 struct iscsi_cls_conn {
         struct list_head conn_list;     /* item in connlist */
         void *dd_data;                  /* LLD private data */