sgi-xpc: prevent false heartbeat failures

The heartbeat timeout functionality in sgi-xpc is currently not trained to
the connection time.  If a connection is made and the code is in the last
polling window prior to doing a timeout, the next polling window will see
the heartbeat as unchanged and initiate a no-heartbeat disconnect.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 43 insertions, 80 deletions

diff --git a/drivers/misc/sgi-xp/xpc_uv.c b/drivers/misc/sgi-xp/xpc_uv.c
index f7fff4727edb..97f7cb21a0a2 100644
--- a/drivers/misc/sgi-xp/xpc_uv.c
+++ b/drivers/misc/sgi-xp/xpc_uv.c
@@ -46,8 +46,7 @@ struct uv_IO_APIC_route_entry {
 };
 #endif
 
-static atomic64_t xpc_heartbeat_uv;
-static DECLARE_BITMAP(xpc_heartbeating_to_mask_uv, XP_MAX_NPARTITIONS_UV);
+static struct xpc_heartbeat_uv *xpc_heartbeat_uv;
 
 #define XPC_ACTIVATE_MSG_SIZE_UV        (1 * GRU_CACHE_LINE_BYTES)
 #define XPC_ACTIVATE_MQ_SIZE_UV         (4 * XP_MAX_NPARTITIONS_UV * \
@@ -423,41 +422,6 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
                 /* syncing of remote_act_state was just done above */
                 break;
 
-        case XPC_ACTIVATE_MQ_MSG_INC_HEARTBEAT_UV: {
-                struct xpc_activate_mq_msg_heartbeat_req_uv *msg;
-
-                msg = container_of(msg_hdr,
-                                   struct xpc_activate_mq_msg_heartbeat_req_uv,
-                                   hdr);
-                part_uv->heartbeat = msg->heartbeat;
-                break;
-        }
-        case XPC_ACTIVATE_MQ_MSG_OFFLINE_HEARTBEAT_UV: {
-                struct xpc_activate_mq_msg_heartbeat_req_uv *msg;
-
-                msg = container_of(msg_hdr,
-                                   struct xpc_activate_mq_msg_heartbeat_req_uv,
-                                   hdr);
-                part_uv->heartbeat = msg->heartbeat;
-
-                spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
-                part_uv->flags |= XPC_P_HEARTBEAT_OFFLINE_UV;
-                spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
-                break;
-        }
-        case XPC_ACTIVATE_MQ_MSG_ONLINE_HEARTBEAT_UV: {
-                struct xpc_activate_mq_msg_heartbeat_req_uv *msg;
-
-                msg = container_of(msg_hdr,
-                                   struct xpc_activate_mq_msg_heartbeat_req_uv,
-                                   hdr);
-                part_uv->heartbeat = msg->heartbeat;
-
-                spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
-                part_uv->flags &= ~XPC_P_HEARTBEAT_OFFLINE_UV;
-                spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
-                break;
-        }
         case XPC_ACTIVATE_MQ_MSG_ACTIVATE_REQ_UV: {
                 struct xpc_activate_mq_msg_activate_req_uv *msg;
 
@@ -475,6 +439,7 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
                 part_uv->act_state_req = XPC_P_ASR_ACTIVATE_UV;
                 part->remote_rp_pa = msg->rp_gpa; /* !!! _pa is _gpa */
                 part->remote_rp_ts_jiffies = msg_hdr->rp_ts_jiffies;
+                part_uv->heartbeat_gpa = msg->heartbeat_gpa;
 
                 if (msg->activate_gru_mq_desc_gpa !=
                     part_uv->activate_gru_mq_desc_gpa) {
@@ -759,7 +724,7 @@ xpc_send_local_activate_IRQ_uv(struct xpc_partition *part, int act_state_req)
 
         /*
          * !!! Make our side think that the remote partition sent an activate
-         * !!! message our way by doing what the activate IRQ handler would
+         * !!! mq message our way by doing what the activate IRQ handler would
          * !!! do had one really been sent.
          */
 
@@ -808,88 +773,80 @@ xpc_get_partition_rsvd_page_pa_uv(void *buf, u64 *cookie, unsigned long *rp_pa,
 static int
 xpc_setup_rsvd_page_sn_uv(struct xpc_rsvd_page *rp)
 {
-        rp->sn.activate_gru_mq_desc_gpa =
+        xpc_heartbeat_uv =
+            &xpc_partitions[sn_partition_id].sn.uv.cached_heartbeat;
+        rp->sn.uv.heartbeat_gpa = uv_gpa(xpc_heartbeat_uv);
+        rp->sn.uv.activate_gru_mq_desc_gpa =
             uv_gpa(xpc_activate_mq_uv->gru_mq_desc);
         return 0;
 }
 
 static void
-xpc_send_heartbeat_uv(int msg_type)
+xpc_allow_hb_uv(short partid)
 {
-        short partid;
-        struct xpc_partition *part;
-        struct xpc_activate_mq_msg_heartbeat_req_uv msg;
-
-        /*
-         * !!! On uv we're broadcasting a heartbeat message every 5 seconds.
-         * !!! Whereas on sn2 we're bte_copy'ng the heartbeat info every 20
-         * !!! seconds. This is an increase in numalink traffic.
-         * ??? Is this good?
-         */
-
-        msg.heartbeat = atomic64_inc_return(&xpc_heartbeat_uv);
-
-        partid = find_first_bit(xpc_heartbeating_to_mask_uv,
-                                XP_MAX_NPARTITIONS_UV);
-
-        while (partid < XP_MAX_NPARTITIONS_UV) {
-                part = &xpc_partitions[partid];
+}
 
-                xpc_send_activate_IRQ_part_uv(part, &msg, sizeof(msg),
-                                              msg_type);
+static void
+xpc_disallow_hb_uv(short partid)
+{
+}
 
-                partid = find_next_bit(xpc_heartbeating_to_mask_uv,
-                                       XP_MAX_NPARTITIONS_UV, partid + 1);
-        }
+static void
+xpc_disallow_all_hbs_uv(void)
+{
 }
 
 static void
 xpc_increment_heartbeat_uv(void)
 {
-        xpc_send_heartbeat_uv(XPC_ACTIVATE_MQ_MSG_INC_HEARTBEAT_UV);
+        xpc_heartbeat_uv->value++;
 }
 
 static void
 xpc_offline_heartbeat_uv(void)
 {
-        xpc_send_heartbeat_uv(XPC_ACTIVATE_MQ_MSG_OFFLINE_HEARTBEAT_UV);
+        xpc_increment_heartbeat_uv();
+        xpc_heartbeat_uv->offline = 1;
 }
 
 static void
 xpc_online_heartbeat_uv(void)
 {
-        xpc_send_heartbeat_uv(XPC_ACTIVATE_MQ_MSG_ONLINE_HEARTBEAT_UV);
+        xpc_increment_heartbeat_uv();
+        xpc_heartbeat_uv->offline = 0;
 }
 
 static void
 xpc_heartbeat_init_uv(void)
 {
-        atomic64_set(&xpc_heartbeat_uv, 0);
-        bitmap_zero(xpc_heartbeating_to_mask_uv, XP_MAX_NPARTITIONS_UV);
-        xpc_heartbeating_to_mask = &xpc_heartbeating_to_mask_uv[0];
+        xpc_heartbeat_uv->value = 1;
+        xpc_heartbeat_uv->offline = 0;
 }
 
 static void
 xpc_heartbeat_exit_uv(void)
 {
-        xpc_send_heartbeat_uv(XPC_ACTIVATE_MQ_MSG_OFFLINE_HEARTBEAT_UV);
+        xpc_offline_heartbeat_uv();
 }
 
 static enum xp_retval
 xpc_get_remote_heartbeat_uv(struct xpc_partition *part)
 {
         struct xpc_partition_uv *part_uv = &part->sn.uv;
-        enum xp_retval ret = xpNoHeartbeat;
+        enum xp_retval ret;
 
-        if (part_uv->remote_act_state != XPC_P_AS_INACTIVE &&
-            part_uv->remote_act_state != XPC_P_AS_DEACTIVATING) {
+        ret = xp_remote_memcpy(uv_gpa(&part_uv->cached_heartbeat),
+                               part_uv->heartbeat_gpa,
+                               sizeof(struct xpc_heartbeat_uv));
+        if (ret != xpSuccess)
+                return ret;
 
-                if (part_uv->heartbeat != part->last_heartbeat ||
-                    (part_uv->flags & XPC_P_HEARTBEAT_OFFLINE_UV)) {
+        if (part_uv->cached_heartbeat.value == part->last_heartbeat &&
+            !part_uv->cached_heartbeat.offline) {
 
-                        part->last_heartbeat = part_uv->heartbeat;
-                        ret = xpSuccess;
-                }
+                ret = xpNoHeartbeat;
+        } else {
+                part->last_heartbeat = part_uv->cached_heartbeat.value;
         }
         return ret;
 }
@@ -904,8 +861,9 @@ xpc_request_partition_activation_uv(struct xpc_rsvd_page *remote_rp,
 
         part->remote_rp_pa = remote_rp_gpa; /* !!! _pa here is really _gpa */
         part->remote_rp_ts_jiffies = remote_rp->ts_jiffies;
+        part->sn.uv.heartbeat_gpa = remote_rp->sn.uv.heartbeat_gpa;
         part->sn.uv.activate_gru_mq_desc_gpa =
-            remote_rp->sn.activate_gru_mq_desc_gpa;
+            remote_rp->sn.uv.activate_gru_mq_desc_gpa;
 
         /*
          * ??? Is it a good idea to make this conditional on what is
@@ -913,8 +871,9 @@ xpc_request_partition_activation_uv(struct xpc_rsvd_page *remote_rp,
          */
         if (part->sn.uv.remote_act_state == XPC_P_AS_INACTIVE) {
                 msg.rp_gpa = uv_gpa(xpc_rsvd_page);
+                msg.heartbeat_gpa = xpc_rsvd_page->sn.uv.heartbeat_gpa;
                 msg.activate_gru_mq_desc_gpa =
-                    xpc_rsvd_page->sn.activate_gru_mq_desc_gpa;
+                    xpc_rsvd_page->sn.uv.activate_gru_mq_desc_gpa;
                 xpc_send_activate_IRQ_part_uv(part, &msg, sizeof(msg),
                                            XPC_ACTIVATE_MQ_MSG_ACTIVATE_REQ_UV);
         }
@@ -1677,6 +1636,10 @@ xpc_init_uv(void)
         xpc_process_activate_IRQ_rcvd = xpc_process_activate_IRQ_rcvd_uv;
         xpc_get_partition_rsvd_page_pa = xpc_get_partition_rsvd_page_pa_uv;
         xpc_setup_rsvd_page_sn = xpc_setup_rsvd_page_sn_uv;
+
+        xpc_allow_hb = xpc_allow_hb_uv;
+        xpc_disallow_hb = xpc_disallow_hb_uv;
+        xpc_disallow_all_hbs = xpc_disallow_all_hbs_uv;
         xpc_increment_heartbeat = xpc_increment_heartbeat_uv;
         xpc_offline_heartbeat = xpc_offline_heartbeat_uv;
         xpc_online_heartbeat = xpc_online_heartbeat_uv;