sgi-xpc: implement opencomplete messaging

sgi-xpc has a window of failure where an open message can be sent and a
subsequent data message can get lost.  We have added a new message
(opencomplete) which closes that window.

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>

5 files changed, 124 insertions, 61 deletions

diff --git a/drivers/misc/sgi-xp/xpc.h b/drivers/misc/sgi-xp/xpc.h
index da32bbe8caaf..a54047674785 100644
--- a/drivers/misc/sgi-xp/xpc.h
+++ b/drivers/misc/sgi-xp/xpc.h
@@ -232,9 +232,10 @@ struct xpc_activate_mq_msghdr_uv {
 #define XPC_ACTIVATE_MQ_MSG_CHCTL_CLOSEREPLY_UV         4
 #define XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREQUEST_UV        5
 #define XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREPLY_UV          6
+#define XPC_ACTIVATE_MQ_MSG_CHCTL_OPENCOMPLETE_UV       7
 
-#define XPC_ACTIVATE_MQ_MSG_MARK_ENGAGED_UV             7
-#define XPC_ACTIVATE_MQ_MSG_MARK_DISENGAGED_UV          8
+#define XPC_ACTIVATE_MQ_MSG_MARK_ENGAGED_UV             8
+#define XPC_ACTIVATE_MQ_MSG_MARK_DISENGAGED_UV          9
 
 struct xpc_activate_mq_msg_uv {
         struct xpc_activate_mq_msghdr_uv hdr;
@@ -278,6 +279,11 @@ struct xpc_activate_mq_msg_chctl_openreply_uv {
         unsigned long notify_gru_mq_desc_gpa;
 };
 
+struct xpc_activate_mq_msg_chctl_opencomplete_uv {
+        struct xpc_activate_mq_msghdr_uv hdr;
+        short ch_number;
+};
+
 /*
  * Functions registered by add_timer() or called by kernel_thread() only
  * allow for a single 64-bit argument. The following macros can be used to
@@ -583,30 +589,32 @@ struct xpc_channel {
 
 #define XPC_C_WASCONNECTED      0x00000001      /* channel was connected */
 
-#define XPC_C_ROPENREPLY        0x00000002      /* remote open channel reply */
-#define XPC_C_OPENREPLY         0x00000004      /* local open channel reply */
-#define XPC_C_ROPENREQUEST      0x00000008     /* remote open channel request */
-#define XPC_C_OPENREQUEST       0x00000010      /* local open channel request */
+#define XPC_C_ROPENCOMPLETE     0x00000002    /* remote open channel complete */
+#define XPC_C_OPENCOMPLETE      0x00000004     /* local open channel complete */
+#define XPC_C_ROPENREPLY        0x00000008      /* remote open channel reply */
+#define XPC_C_OPENREPLY         0x00000010      /* local open channel reply */
+#define XPC_C_ROPENREQUEST      0x00000020     /* remote open channel request */
+#define XPC_C_OPENREQUEST       0x00000040      /* local open channel request */
 
-#define XPC_C_SETUP             0x00000020 /* channel's msgqueues are alloc'd */
-#define XPC_C_CONNECTEDCALLOUT  0x00000040     /* connected callout initiated */
+#define XPC_C_SETUP             0x00000080 /* channel's msgqueues are alloc'd */
+#define XPC_C_CONNECTEDCALLOUT  0x00000100     /* connected callout initiated */
 #define XPC_C_CONNECTEDCALLOUT_MADE \
-                                0x00000080     /* connected callout completed */
-#define XPC_C_CONNECTED         0x00000100      /* local channel is connected */
-#define XPC_C_CONNECTING        0x00000200      /* channel is being connected */
+                                0x00000200     /* connected callout completed */
+#define XPC_C_CONNECTED         0x00000400      /* local channel is connected */
+#define XPC_C_CONNECTING        0x00000800      /* channel is being connected */
 
-#define XPC_C_RCLOSEREPLY       0x00000400      /* remote close channel reply */
-#define XPC_C_CLOSEREPLY        0x00000800      /* local close channel reply */
-#define XPC_C_RCLOSEREQUEST     0x00001000    /* remote close channel request */
-#define XPC_C_CLOSEREQUEST      0x00002000     /* local close channel request */
+#define XPC_C_RCLOSEREPLY       0x00001000      /* remote close channel reply */
+#define XPC_C_CLOSEREPLY        0x00002000      /* local close channel reply */
+#define XPC_C_RCLOSEREQUEST     0x00004000    /* remote close channel request */
+#define XPC_C_CLOSEREQUEST      0x00008000     /* local close channel request */
 
-#define XPC_C_DISCONNECTED      0x00004000      /* channel is disconnected */
-#define XPC_C_DISCONNECTING     0x00008000   /* channel is being disconnected */
+#define XPC_C_DISCONNECTED      0x00010000      /* channel is disconnected */
+#define XPC_C_DISCONNECTING     0x00020000   /* channel is being disconnected */
 #define XPC_C_DISCONNECTINGCALLOUT \
-                                0x00010000 /* disconnecting callout initiated */
+                                0x00040000 /* disconnecting callout initiated */
 #define XPC_C_DISCONNECTINGCALLOUT_MADE \
-                                0x00020000 /* disconnecting callout completed */
-#define XPC_C_WDISCONNECT       0x00040000  /* waiting for channel disconnect */
+                                0x00080000 /* disconnecting callout completed */
+#define XPC_C_WDISCONNECT       0x00100000  /* waiting for channel disconnect */
 
 /*
  * The channel control flags (chctl) union consists of a 64-bit variable which
@@ -625,11 +633,13 @@ union xpc_channel_ctl_flags {
 #define XPC_CHCTL_CLOSEREPLY    0x02
 #define XPC_CHCTL_OPENREQUEST   0x04
 #define XPC_CHCTL_OPENREPLY     0x08
-#define XPC_CHCTL_MSGREQUEST    0x10
+#define XPC_CHCTL_OPENCOMPLETE  0x10
+#define XPC_CHCTL_MSGREQUEST    0x20
 
 #define XPC_OPENCLOSE_CHCTL_FLAGS \
                         (XPC_CHCTL_CLOSEREQUEST | XPC_CHCTL_CLOSEREPLY | \
-                         XPC_CHCTL_OPENREQUEST | XPC_CHCTL_OPENREPLY)
+                         XPC_CHCTL_OPENREQUEST | XPC_CHCTL_OPENREPLY | \
+                         XPC_CHCTL_OPENCOMPLETE)
 #define XPC_MSG_CHCTL_FLAGS     XPC_CHCTL_MSGREQUEST
 
 static inline int
@@ -866,6 +876,8 @@ extern void (*xpc_send_chctl_closereply) (struct xpc_channel *,
 extern void (*xpc_send_chctl_openrequest) (struct xpc_channel *,
                                            unsigned long *);
 extern void (*xpc_send_chctl_openreply) (struct xpc_channel *, unsigned long *);
+extern void (*xpc_send_chctl_opencomplete) (struct xpc_channel *,
+                                            unsigned long *);
 
 extern enum xp_retval (*xpc_save_remote_msgqueue_pa) (struct xpc_channel *,
                                                       unsigned long);
diff --git a/drivers/misc/sgi-xp/xpc_channel.c b/drivers/misc/sgi-xp/xpc_channel.c
index 99a2534c38a1..2eb3abff0e3a 100644
--- a/drivers/misc/sgi-xp/xpc_channel.c
+++ b/drivers/misc/sgi-xp/xpc_channel.c
@@ -3,7 +3,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2004-2009 Silicon Graphics, Inc.  All Rights Reserved.
  */
 
 /*
@@ -44,10 +44,10 @@ xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags)
 
                 if (ret != xpSuccess)
                         XPC_DISCONNECT_CHANNEL(ch, ret, irq_flags);
+                else
+                        ch->flags |= XPC_C_SETUP;
 
-                ch->flags |= XPC_C_SETUP;
-
-                if (ch->flags & (XPC_C_CONNECTED | XPC_C_DISCONNECTING))
+                if (ch->flags & XPC_C_DISCONNECTING)
                         return;
         }
 
@@ -59,14 +59,18 @@ xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags)
         if (!(ch->flags & XPC_C_ROPENREPLY))
                 return;
 
-        ch->flags = (XPC_C_CONNECTED | XPC_C_SETUP);    /* clear all else */
+        if (!(ch->flags & XPC_C_OPENCOMPLETE)) {
+                ch->flags |= (XPC_C_OPENCOMPLETE | XPC_C_CONNECTED);
+                xpc_send_chctl_opencomplete(ch, irq_flags);
+        }
+
+        if (!(ch->flags & XPC_C_ROPENCOMPLETE))
+                return;
 
         dev_info(xpc_chan, "channel %d to partition %d connected\n",
                  ch->number, ch->partid);
 
-        spin_unlock_irqrestore(&ch->lock, *irq_flags);
-        xpc_create_kthreads(ch, 1, 0);
-        spin_lock_irqsave(&ch->lock, *irq_flags);
+        ch->flags = (XPC_C_CONNECTED | XPC_C_SETUP);    /* clear all else */
 }
 
 /*
@@ -184,6 +188,7 @@ xpc_process_openclose_chctl_flags(struct xpc_partition *part, int ch_number,
         struct xpc_channel *ch = &part->channels[ch_number];
         enum xp_retval reason;
         enum xp_retval ret;
+        int create_kthread = 0;
 
         spin_lock_irqsave(&ch->lock, irq_flags);
 
@@ -196,8 +201,7 @@ again:
                  * has had a chance to see that the channel is disconnected.
                  */
                 ch->delayed_chctl_flags |= chctl_flags;
-                spin_unlock_irqrestore(&ch->lock, irq_flags);
-                return;
+                goto out;
         }
 
         if (chctl_flags & XPC_CHCTL_CLOSEREQUEST) {
@@ -239,8 +243,7 @@ again:
                                             XPC_CHCTL_CLOSEREQUEST;
                                         spin_unlock(&part->chctl_lock);
                                 }
-                                spin_unlock_irqrestore(&ch->lock, irq_flags);
-                                return;
+                                goto out;
                         }
 
                         XPC_SET_REASON(ch, 0, 0);
@@ -250,7 +253,8 @@ again:
                         ch->flags |= (XPC_C_CONNECTING | XPC_C_ROPENREQUEST);
                 }
 
-                chctl_flags &= ~(XPC_CHCTL_OPENREQUEST | XPC_CHCTL_OPENREPLY);
+                chctl_flags &= ~(XPC_CHCTL_OPENREQUEST | XPC_CHCTL_OPENREPLY |
+                    XPC_CHCTL_OPENCOMPLETE);
 
                 /*
                  * The meaningful CLOSEREQUEST connection state fields are:
@@ -269,8 +273,7 @@ again:
                         XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
 
                         DBUG_ON(chctl_flags & XPC_CHCTL_CLOSEREPLY);
-                        spin_unlock_irqrestore(&ch->lock, irq_flags);
-                        return;
+                        goto out;
                 }
 
                 xpc_process_disconnect(ch, &irq_flags);
@@ -283,8 +286,7 @@ again:
 
                 if (ch->flags & XPC_C_DISCONNECTED) {
                         DBUG_ON(part->act_state != XPC_P_AS_DEACTIVATING);
-                        spin_unlock_irqrestore(&ch->lock, irq_flags);
-                        return;
+                        goto out;
                 }
 
                 DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
@@ -299,8 +301,7 @@ again:
                                     XPC_CHCTL_CLOSEREPLY;
                                 spin_unlock(&part->chctl_lock);
                         }
-                        spin_unlock_irqrestore(&ch->lock, irq_flags);
-                        return;
+                        goto out;
                 }
 
                 ch->flags |= XPC_C_RCLOSEREPLY;
@@ -320,14 +321,12 @@ again:
 
                 if (part->act_state == XPC_P_AS_DEACTIVATING ||
                     (ch->flags & XPC_C_ROPENREQUEST)) {
-                        spin_unlock_irqrestore(&ch->lock, irq_flags);
-                        return;
+                        goto out;
                 }
 
                 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) {
                         ch->delayed_chctl_flags |= XPC_CHCTL_OPENREQUEST;
-                        spin_unlock_irqrestore(&ch->lock, irq_flags);
-                        return;
+                        goto out;
                 }
                 DBUG_ON(!(ch->flags & (XPC_C_DISCONNECTED |
                                        XPC_C_OPENREQUEST)));
@@ -341,8 +340,7 @@ again:
                  */
                 if (args->entry_size == 0 || args->local_nentries == 0) {
                         /* assume OPENREQUEST was delayed by mistake */
-                        spin_unlock_irqrestore(&ch->lock, irq_flags);
-                        return;
+                        goto out;
                 }
 
                 ch->flags |= (XPC_C_ROPENREQUEST | XPC_C_CONNECTING);
@@ -352,8 +350,7 @@ again:
                         if (args->entry_size != ch->entry_size) {
                                 XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,
                                                        &irq_flags);
-                                spin_unlock_irqrestore(&ch->lock, irq_flags);
-                                return;
+                                goto out;
                         }
                 } else {
                         ch->entry_size = args->entry_size;
@@ -375,15 +372,13 @@ again:
                         args->local_msgqueue_pa, args->local_nentries,
                         args->remote_nentries, ch->partid, ch->number);
 
-                if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED)) {
-                        spin_unlock_irqrestore(&ch->lock, irq_flags);
-                        return;
-                }
+                if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
+                        goto out;
+
                 if (!(ch->flags & XPC_C_OPENREQUEST)) {
                         XPC_DISCONNECT_CHANNEL(ch, xpOpenCloseError,
                                                &irq_flags);
-                        spin_unlock_irqrestore(&ch->lock, irq_flags);
-                        return;
+                        goto out;
                 }
 
                 DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));
@@ -403,8 +398,7 @@ again:
                 ret = xpc_save_remote_msgqueue_pa(ch, args->local_msgqueue_pa);
                 if (ret != xpSuccess) {
                         XPC_DISCONNECT_CHANNEL(ch, ret, &irq_flags);
-                        spin_unlock_irqrestore(&ch->lock, irq_flags);
-                        return;
+                        goto out;
                 }
                 ch->flags |= XPC_C_ROPENREPLY;
 
@@ -430,7 +424,36 @@ again:
                 xpc_process_connect(ch, &irq_flags);
         }
 
+        if (chctl_flags & XPC_CHCTL_OPENCOMPLETE) {
+
+                dev_dbg(xpc_chan, "XPC_CHCTL_OPENCOMPLETE received from "
+                        "partid=%d, channel=%d\n", ch->partid, ch->number);
+
+                if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
+                        goto out;
+
+                if (!(ch->flags & XPC_C_OPENREQUEST) ||
+                    !(ch->flags & XPC_C_OPENREPLY)) {
+                        XPC_DISCONNECT_CHANNEL(ch, xpOpenCloseError,
+                                               &irq_flags);
+                        goto out;
+                }
+
+                DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));
+                DBUG_ON(!(ch->flags & XPC_C_ROPENREPLY));
+                DBUG_ON(!(ch->flags & XPC_C_CONNECTED));
+
+                ch->flags |= XPC_C_ROPENCOMPLETE;
+
+                xpc_process_connect(ch, &irq_flags);
+                create_kthread = 1;
+        }
+
+out:
         spin_unlock_irqrestore(&ch->lock, irq_flags);
+
+        if (create_kthread)
+                xpc_create_kthreads(ch, 1, 0);
 }
 
 /*
@@ -564,10 +587,6 @@ xpc_process_sent_chctl_flags(struct xpc_partition *part)
                         if (!(ch_flags & XPC_C_OPENREQUEST)) {
                                 DBUG_ON(ch_flags & XPC_C_SETUP);
                                 (void)xpc_connect_channel(ch);
-                        } else {
-                                spin_lock_irqsave(&ch->lock, irq_flags);
-                                xpc_process_connect(ch, &irq_flags);
-                                spin_unlock_irqrestore(&ch->lock, irq_flags);
                         }
                         continue;
                 }
diff --git a/drivers/misc/sgi-xp/xpc_main.c b/drivers/misc/sgi-xp/xpc_main.c
index 34b084cd63da..2bb070e17222 100644
--- a/drivers/misc/sgi-xp/xpc_main.c
+++ b/drivers/misc/sgi-xp/xpc_main.c
@@ -220,6 +220,8 @@ void (*xpc_send_chctl_openrequest) (struct xpc_channel *ch,
                                     unsigned long *irq_flags);
 void (*xpc_send_chctl_openreply) (struct xpc_channel *ch,
                                   unsigned long *irq_flags);
+void (*xpc_send_chctl_opencomplete) (struct xpc_channel *ch,
+                                  unsigned long *irq_flags);
 
 enum xp_retval (*xpc_save_remote_msgqueue_pa) (struct xpc_channel *ch,
                                                unsigned long msgqueue_pa);
diff --git a/drivers/misc/sgi-xp/xpc_sn2.c b/drivers/misc/sgi-xp/xpc_sn2.c
index 43ad2968daf5..09bc1989f216 100644
--- a/drivers/misc/sgi-xp/xpc_sn2.c
+++ b/drivers/misc/sgi-xp/xpc_sn2.c
@@ -431,6 +431,13 @@ xpc_send_chctl_openreply_sn2(struct xpc_channel *ch, unsigned long *irq_flags)
 }
 
 static void
+xpc_send_chctl_opencomplete_sn2(struct xpc_channel *ch,
+                                unsigned long *irq_flags)
+{
+        XPC_SEND_NOTIFY_IRQ_SN2(ch, XPC_CHCTL_OPENCOMPLETE, irq_flags);
+}
+
+static void
 xpc_send_chctl_msgrequest_sn2(struct xpc_channel *ch)
 {
         XPC_SEND_NOTIFY_IRQ_SN2(ch, XPC_CHCTL_MSGREQUEST, NULL);
@@ -2380,6 +2387,7 @@ xpc_init_sn2(void)
         xpc_send_chctl_closereply = xpc_send_chctl_closereply_sn2;
         xpc_send_chctl_openrequest = xpc_send_chctl_openrequest_sn2;
         xpc_send_chctl_openreply = xpc_send_chctl_openreply_sn2;
+        xpc_send_chctl_opencomplete = xpc_send_chctl_opencomplete_sn2;
 
         xpc_save_remote_msgqueue_pa = xpc_save_remote_msgqueue_pa_sn2;
 
diff --git a/drivers/misc/sgi-xp/xpc_uv.c b/drivers/misc/sgi-xp/xpc_uv.c
index 97f7cb21a0a2..1e475b4c0887 100644
--- a/drivers/misc/sgi-xp/xpc_uv.c
+++ b/drivers/misc/sgi-xp/xpc_uv.c
@@ -534,6 +534,17 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
                 xpc_wakeup_channel_mgr(part);
                 break;
         }
+        case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENCOMPLETE_UV: {
+                struct xpc_activate_mq_msg_chctl_opencomplete_uv *msg;
+
+                msg = container_of(msg_hdr, struct
+                                xpc_activate_mq_msg_chctl_opencomplete_uv, hdr);
+                spin_lock_irqsave(&part->chctl_lock, irq_flags);
+                part->chctl.flags[msg->ch_number] |= XPC_CHCTL_OPENCOMPLETE;
+                spin_unlock_irqrestore(&part->chctl_lock, irq_flags);
+
+                xpc_wakeup_channel_mgr(part);
+        }
         case XPC_ACTIVATE_MQ_MSG_MARK_ENGAGED_UV:
                 spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
                 part_uv->flags |= XPC_P_ENGAGED_UV;
@@ -1202,6 +1213,16 @@ xpc_send_chctl_openreply_uv(struct xpc_channel *ch, unsigned long *irq_flags)
 }
 
 static void
+xpc_send_chctl_opencomplete_uv(struct xpc_channel *ch, unsigned long *irq_flags)
+{
+        struct xpc_activate_mq_msg_chctl_opencomplete_uv msg;
+
+        msg.ch_number = ch->number;
+        xpc_send_activate_IRQ_ch_uv(ch, irq_flags, &msg, sizeof(msg),
+                                    XPC_ACTIVATE_MQ_MSG_CHCTL_OPENCOMPLETE_UV);
+}
+
+static void
 xpc_send_chctl_local_msgrequest_uv(struct xpc_partition *part, int ch_number)
 {
         unsigned long irq_flags;
@@ -1665,6 +1686,7 @@ xpc_init_uv(void)
         xpc_send_chctl_closereply = xpc_send_chctl_closereply_uv;
         xpc_send_chctl_openrequest = xpc_send_chctl_openrequest_uv;
         xpc_send_chctl_openreply = xpc_send_chctl_openreply_uv;
+        xpc_send_chctl_opencomplete = xpc_send_chctl_opencomplete_uv;
 
         xpc_save_remote_msgqueue_pa = xpc_save_remote_msgqueue_pa_uv;