[SCSI] iscsi_transport: Added Ping support

Added ping support for iscsi adapter, application can use this
interface for diagnostic network connection.

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, 84 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 38f0bf8ea91a..a20f1813cb51 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -1507,6 +1507,35 @@ void iscsi_post_host_event(uint32_t host_no, struct iscsi_transport *transport,
 }
 EXPORT_SYMBOL_GPL(iscsi_post_host_event);
 
+void iscsi_ping_comp_event(uint32_t host_no, struct iscsi_transport *transport,
+                           uint32_t status, uint32_t pid, 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 ping comp: OOM\n");
+                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_PING_COMP;
+        ev->r.ping_comp.host_no = host_no;
+        ev->r.ping_comp.status = status;
+        ev->r.ping_comp.pid = pid;
+        ev->r.ping_comp.data_size = data_size;
+        memcpy((char *)ev + sizeof(*ev), data, data_size);
+
+        iscsi_multicast_skb(skb, ISCSI_NL_GRP_ISCSID, GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(iscsi_ping_comp_event);
+
 static int
 iscsi_if_send_reply(uint32_t group, int seq, int type, int done, int multi,
                     void *payload, int size)
@@ -1946,6 +1975,33 @@ iscsi_set_iface_params(struct iscsi_transport *transport,
 }
 
 static int
+iscsi_send_ping(struct iscsi_transport *transport, struct iscsi_uevent *ev)
+{
+        struct Scsi_Host *shost;
+        struct sockaddr *dst_addr;
+        int err;
+
+        if (!transport->send_ping)
+                return -ENOSYS;
+
+        shost = scsi_host_lookup(ev->u.iscsi_ping.host_no);
+        if (!shost) {
+                printk(KERN_ERR "iscsi_ping could not find host no %u\n",
+                       ev->u.iscsi_ping.host_no);
+                return -ENODEV;
+        }
+
+        dst_addr = (struct sockaddr *)((char *)ev + sizeof(*ev));
+        err = transport->send_ping(shost, ev->u.iscsi_ping.iface_num,
+                                   ev->u.iscsi_ping.iface_type,
+                                   ev->u.iscsi_ping.payload_size,
+                                   ev->u.iscsi_ping.pid,
+                                   dst_addr);
+        scsi_host_put(shost);
+        return err;
+}
+
+static int
 iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, uint32_t *group)
 {
         int err = 0;
@@ -2090,6 +2146,9 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, uint32_t *group)
                 err = iscsi_set_iface_params(transport, ev,
                                              nlmsg_attrlen(nlh, sizeof(*ev)));
                 break;
+        case ISCSI_UEVENT_PING:
+                err = iscsi_send_ping(transport, ev);
+                break;
         default:
                 err = -ENOSYS;
                 break;
diff --git a/include/scsi/iscsi_if.h b/include/scsi/iscsi_if.h
index 3aac99155e80..7ff9678b7e79 100644
--- a/include/scsi/iscsi_if.h
+++ b/include/scsi/iscsi_if.h
@@ -60,6 +60,7 @@ enum iscsi_uevent_e {
 
         ISCSI_UEVENT_PATH_UPDATE        = UEVENT_BASE + 20,
         ISCSI_UEVENT_SET_IFACE_PARAMS   = UEVENT_BASE + 21,
+        ISCSI_UEVENT_PING               = UEVENT_BASE + 22,
 
         /* up events */
         ISCSI_KEVENT_RECV_PDU           = KEVENT_BASE + 1,
@@ -73,6 +74,7 @@ enum iscsi_uevent_e {
         ISCSI_KEVENT_IF_DOWN            = KEVENT_BASE + 8,
         ISCSI_KEVENT_CONN_LOGIN_STATE   = KEVENT_BASE + 9,
         ISCSI_KEVENT_HOST_EVENT         = KEVENT_BASE + 10,
+        ISCSI_KEVENT_PING_COMP          = KEVENT_BASE + 11,
 };
 
 enum iscsi_tgt_dscvr {
@@ -186,6 +188,14 @@ struct iscsi_uevent {
                         uint32_t        host_no;
                         uint32_t        count;
                 } set_iface_params;
+                struct msg_iscsi_ping {
+                        uint32_t        host_no;
+                        uint32_t        iface_num;
+                        uint32_t        iface_type;
+                        uint32_t        payload_size;
+                        uint32_t        pid;    /* unique ping id associated
+                                                   with each ping request */
+                } iscsi_ping;
         } u;
         union {
                 /* messages k -> u */
@@ -235,6 +245,13 @@ struct iscsi_uevent {
                         uint32_t        data_size;
                         enum iscsi_host_event_code code;
                 } host_event;
+                struct msg_ping_comp {
+                        uint32_t        host_no;
+                        uint32_t        status;
+                        uint32_t        pid;    /* unique ping id associated
+                                                   with each ping request */
+                        uint32_t        data_size;
+                } ping_comp;
         } r;
 } __attribute__ ((aligned (sizeof(uint64_t))));
 
diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
index 7f047314281b..aede513f99bd 100644
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -144,6 +144,9 @@ struct iscsi_transport {
                                 int param, char *buf);
         umode_t (*attr_is_visible)(int param_type, int param);
         int (*bsg_request)(struct bsg_job *job);
+        int (*send_ping) (struct Scsi_Host *shost, uint32_t iface_num,
+                          uint32_t iface_type, uint32_t payload_size,
+                          uint32_t pid, struct sockaddr *dst_addr);
 };
 
 /*
@@ -172,6 +175,11 @@ extern void iscsi_post_host_event(uint32_t host_no,
                                   uint32_t data_size,
                                   uint8_t *data);
 
+extern void iscsi_ping_comp_event(uint32_t host_no,
+                                  struct iscsi_transport *transport,
+                                  uint32_t status, uint32_t pid,
+                                  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 */