--- /dev/null
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2004-2009 Silicon Graphics, Inc. All Rights Reserved.
+ */
+
+/*
+ * Cross Partition Communication (XPC) channel support.
+ *
+ * This is the part of XPC that manages the channels and
+ * sends/receives messages across them to/from other partitions.
+ *
+ */
+
+#include <linux/device.h>
+#include "xpc.h"
+
+/*
+ * Process a connect message from a remote partition.
+ *
+ * Note: xpc_process_connect() is expecting to be called with the
+ * spin_lock_irqsave held and will leave it locked upon return.
+ */
+static void
+xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags)
+{
+ enum xp_retval ret;
+
+ DBUG_ON(!spin_is_locked(&ch->lock));
+
+ if (!(ch->flags & XPC_C_OPENREQUEST) ||
+ !(ch->flags & XPC_C_ROPENREQUEST)) {
+ /* nothing more to do for now */
+ return;
+ }
+ DBUG_ON(!(ch->flags & XPC_C_CONNECTING));
+
+ if (!(ch->flags & XPC_C_SETUP)) {
+ spin_unlock_irqrestore(&ch->lock, *irq_flags);
+ ret = xpc_arch_ops.setup_msg_structures(ch);
+ spin_lock_irqsave(&ch->lock, *irq_flags);
+
+ if (ret != xpSuccess)
+ XPC_DISCONNECT_CHANNEL(ch, ret, irq_flags);
+ else
+ ch->flags |= XPC_C_SETUP;
+
+ if (ch->flags & XPC_C_DISCONNECTING)
+ return;
+ }
+
+ if (!(ch->flags & XPC_C_OPENREPLY)) {
+ ch->flags |= XPC_C_OPENREPLY;
+ xpc_arch_ops.send_chctl_openreply(ch, irq_flags);
+ }
+
+ if (!(ch->flags & XPC_C_ROPENREPLY))
+ return;
+
+ if (!(ch->flags & XPC_C_OPENCOMPLETE)) {
+ ch->flags |= (XPC_C_OPENCOMPLETE | XPC_C_CONNECTED);
+ xpc_arch_ops.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);
+
+ ch->flags = (XPC_C_CONNECTED | XPC_C_SETUP); /* clear all else */
+}
+
+/*
+ * spin_lock_irqsave() is expected to be held on entry.
+ */
+static void
+xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags)
+{
+ struct xpc_partition *part = &xpc_partitions[ch->partid];
+ u32 channel_was_connected = (ch->flags & XPC_C_WASCONNECTED);
+
+ DBUG_ON(!spin_is_locked(&ch->lock));
+
+ if (!(ch->flags & XPC_C_DISCONNECTING))
+ return;
+
+ DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
+
+ /* make sure all activity has settled down first */
+
+ if (atomic_read(&ch->kthreads_assigned) > 0 ||
+ atomic_read(&ch->references) > 0) {
+ return;
+ }
+ DBUG_ON((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
+ !(ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE));
+
+ if (part->act_state == XPC_P_AS_DEACTIVATING) {
+ /* can't proceed until the other side disengages from us */
+ if (xpc_arch_ops.partition_engaged(ch->partid))
+ return;
+
+ } else {
+
+ /* as long as the other side is up do the full protocol */
+
+ if (!(ch->flags & XPC_C_RCLOSEREQUEST))
+ return;
+
+ if (!(ch->flags & XPC_C_CLOSEREPLY)) {
+ ch->flags |= XPC_C_CLOSEREPLY;
+ xpc_arch_ops.send_chctl_closereply(ch, irq_flags);
+ }
+
+ if (!(ch->flags & XPC_C_RCLOSEREPLY))
+ return;
+ }
+
+ /* wake those waiting for notify completion */
+ if (atomic_read(&ch->n_to_notify) > 0) {
+ /* we do callout while holding ch->lock, callout can't block */
+ xpc_arch_ops.notify_senders_of_disconnect(ch);
+ }
+
+ /* both sides are disconnected now */
+
+ if (ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE) {
+ spin_unlock_irqrestore(&ch->lock, *irq_flags);
+ xpc_disconnect_callout(ch, xpDisconnected);
+ spin_lock_irqsave(&ch->lock, *irq_flags);
+ }
+
+ DBUG_ON(atomic_read(&ch->n_to_notify) != 0);
+
+ /* it's now safe to free the channel's message queues */
+ xpc_arch_ops.teardown_msg_structures(ch);
+
+ ch->func = NULL;
+ ch->key = NULL;
+ ch->entry_size = 0;
+ ch->local_nentries = 0;
+ ch->remote_nentries = 0;
+ ch->kthreads_assigned_limit = 0;
+ ch->kthreads_idle_limit = 0;
+
+ /*
+ * Mark the channel disconnected and clear all other flags, including
+ * XPC_C_SETUP (because of call to
+ * xpc_arch_ops.teardown_msg_structures()) but not including
+ * XPC_C_WDISCONNECT (if it was set).
+ */
+ ch->flags = (XPC_C_DISCONNECTED | (ch->flags & XPC_C_WDISCONNECT));
+
+ atomic_dec(&part->nchannels_active);
+
+ if (channel_was_connected) {
+ dev_info(xpc_chan, "channel %d to partition %d disconnected, "
+ "reason=%d\n", ch->number, ch->partid, ch->reason);
+ }
+
+ if (ch->flags & XPC_C_WDISCONNECT) {
+ /* we won't lose the CPU since we're holding ch->lock */
+ complete(&ch->wdisconnect_wait);
+ } else if (ch->delayed_chctl_flags) {
+ if (part->act_state != XPC_P_AS_DEACTIVATING) {
+ /* time to take action on any delayed chctl flags */
+ spin_lock(&part->chctl_lock);
+ part->chctl.flags[ch->number] |=
+ ch->delayed_chctl_flags;
+ spin_unlock(&part->chctl_lock);
+ }
+ ch->delayed_chctl_flags = 0;
+ }
+}
+
+/*
+ * Process a change in the channel's remote connection state.
+ */
+static void
+xpc_process_openclose_chctl_flags(struct xpc_partition *part, int ch_number,
+ u8 chctl_flags)
+{
+ unsigned long irq_flags;
+ struct xpc_openclose_args *args =
+ &part->remote_openclose_args[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);
+
+again:
+
+ if ((ch->flags & XPC_C_DISCONNECTED) &&
+ (ch->flags & XPC_C_WDISCONNECT)) {
+ /*
+ * Delay processing chctl flags until thread waiting disconnect
+ * has had a chance to see that the channel is disconnected.
+ */
+ ch->delayed_chctl_flags |= chctl_flags;
+ goto out;
+ }
+
+ if (chctl_flags & XPC_CHCTL_CLOSEREQUEST) {
+
+ dev_dbg(xpc_chan, "XPC_CHCTL_CLOSEREQUEST (reason=%d) received "
+ "from partid=%d, channel=%d\n", args->reason,
+ ch->partid, ch->number);
+
+ /*
+ * If RCLOSEREQUEST is set, we're probably waiting for
+ * RCLOSEREPLY. We should find it and a ROPENREQUEST packed
+ * with this RCLOSEREQUEST in the chctl_flags.
+ */
+
+ if (ch->flags & XPC_C_RCLOSEREQUEST) {
+ DBUG_ON(!(ch->flags & XPC_C_DISCONNECTING));
+ DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
+ DBUG_ON(!(ch->flags & XPC_C_CLOSEREPLY));
+ DBUG_ON(ch->flags & XPC_C_RCLOSEREPLY);
+
+ DBUG_ON(!(chctl_flags & XPC_CHCTL_CLOSEREPLY));
+ chctl_flags &= ~XPC_CHCTL_CLOSEREPLY;
+ ch->flags |= XPC_C_RCLOSEREPLY;
+
+ /* both sides have finished disconnecting */
+ xpc_process_disconnect(ch, &irq_flags);
+ DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
+ goto again;
+ }
+
+ if (ch->flags & XPC_C_DISCONNECTED) {
+ if (!(chctl_flags & XPC_CHCTL_OPENREQUEST)) {
+ if (part->chctl.flags[ch_number] &
+ XPC_CHCTL_OPENREQUEST) {
+
+ DBUG_ON(ch->delayed_chctl_flags != 0);
+ spin_lock(&part->chctl_lock);
+ part->chctl.flags[ch_number] |=
+ XPC_CHCTL_CLOSEREQUEST;
+ spin_unlock(&part->chctl_lock);
+ }
+ goto out;
+ }
+
+ XPC_SET_REASON(ch, 0, 0);
+ ch->flags &= ~XPC_C_DISCONNECTED;
+
+ atomic_inc(&part->nchannels_active);
+ ch->flags |= (XPC_C_CONNECTING | XPC_C_ROPENREQUEST);
+ }
+
+ chctl_flags &= ~(XPC_CHCTL_OPENREQUEST | XPC_CHCTL_OPENREPLY |
+ XPC_CHCTL_OPENCOMPLETE);
+
+ /*
+ * The meaningful CLOSEREQUEST connection state fields are:
+ * reason = reason connection is to be closed
+ */
+
+ ch->flags |= XPC_C_RCLOSEREQUEST;
+
+ if (!(ch->flags & XPC_C_DISCONNECTING)) {
+ reason = args->reason;
+ if (reason <= xpSuccess || reason > xpUnknownReason)
+ reason = xpUnknownReason;
+ else if (reason == xpUnregistering)
+ reason = xpOtherUnregistering;
+
+ XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
+
+ DBUG_ON(chctl_flags & XPC_CHCTL_CLOSEREPLY);
+ goto out;
+ }
+
+ xpc_process_disconnect(ch, &irq_flags);
+ }
+
+ if (chctl_flags & XPC_CHCTL_CLOSEREPLY) {
+
+ dev_dbg(xpc_chan, "XPC_CHCTL_CLOSEREPLY received from partid="
+ "%d, channel=%d\n", ch->partid, ch->number);
+
+ if (ch->flags & XPC_C_DISCONNECTED) {
+ DBUG_ON(part->act_state != XPC_P_AS_DEACTIVATING);
+ goto out;
+ }
+
+ DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
+
+ if (!(ch->flags & XPC_C_RCLOSEREQUEST)) {
+ if (part->chctl.flags[ch_number] &
+ XPC_CHCTL_CLOSEREQUEST) {
+
+ DBUG_ON(ch->delayed_chctl_flags != 0);
+ spin_lock(&part->chctl_lock);
+ part->chctl.flags[ch_number] |=
+ XPC_CHCTL_CLOSEREPLY;
+ spin_unlock(&part->chctl_lock);
+ }
+ goto out;
+ }
+
+ ch->flags |= XPC_C_RCLOSEREPLY;
+
+ if (ch->flags & XPC_C_CLOSEREPLY) {
+ /* both sides have finished disconnecting */
+ xpc_process_disconnect(ch, &irq_flags);
+ }
+ }
+
+ if (chctl_flags & XPC_CHCTL_OPENREQUEST) {
+
+ dev_dbg(xpc_chan, "XPC_CHCTL_OPENREQUEST (entry_size=%d, "
+ "local_nentries=%d) received from partid=%d, "
+ "channel=%d\n", args->entry_size, args->local_nentries,
+ ch->partid, ch->number);
+
+ if (part->act_state == XPC_P_AS_DEACTIVATING ||
+ (ch->flags & XPC_C_ROPENREQUEST)) {
+ goto out;
+ }
+
+ if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) {
+ ch->delayed_chctl_flags |= XPC_CHCTL_OPENREQUEST;
+ goto out;
+ }
+ DBUG_ON(!(ch->flags & (XPC_C_DISCONNECTED |
+ XPC_C_OPENREQUEST)));
+ DBUG_ON(ch->flags & (XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |
+ XPC_C_OPENREPLY | XPC_C_CONNECTED));
+
+ /*
+ * The meaningful OPENREQUEST connection state fields are:
+ * entry_size = size of channel's messages in bytes
+ * local_nentries = remote partition's local_nentries
+ */
+ if (args->entry_size == 0 || args->local_nentries == 0) {
+ /* assume OPENREQUEST was delayed by mistake */
+ goto out;
+ }
+
+ ch->flags |= (XPC_C_ROPENREQUEST | XPC_C_CONNECTING);
+ ch->remote_nentries = args->local_nentries;
+
+ if (ch->flags & XPC_C_OPENREQUEST) {
+ if (args->entry_size != ch->entry_size) {
+ XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,
+ &irq_flags);
+ goto out;
+ }
+ } else {
+ ch->entry_size = args->entry_size;
+
+ XPC_SET_REASON(ch, 0, 0);
+ ch->flags &= ~XPC_C_DISCONNECTED;
+
+ atomic_inc(&part->nchannels_active);
+ }
+
+ xpc_process_connect(ch, &irq_flags);
+ }
+
+ if (chctl_flags & XPC_CHCTL_OPENREPLY) {
+
+ dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY (local_msgqueue_pa="
+ "0x%lx, local_nentries=%d, remote_nentries=%d) "
+ "received from partid=%d, channel=%d\n",
+ args->local_msgqueue_pa, args->local_nentries,
+ args->remote_nentries, ch->partid, ch->number);
+
+ if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
+ goto out;
+
+ if (!(ch->flags & XPC_C_OPENREQUEST)) {
+ XPC_DISCONNECT_CHANNEL(ch, xpOpenCloseError,
+ &irq_flags);
+ goto out;
+ }
+
+ DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));
+ DBUG_ON(ch->flags & XPC_C_CONNECTED);
+
+ /*
+ * The meaningful OPENREPLY connection state fields are:
+ * local_msgqueue_pa = physical address of remote
+ * partition's local_msgqueue
+ * local_nentries = remote partition's local_nentries
+ * remote_nentries = remote partition's remote_nentries
+ */
+ DBUG_ON(args->local_msgqueue_pa == 0);
+ DBUG_ON(args->local_nentries == 0);
+ DBUG_ON(args->remote_nentries == 0);
+
+ ret = xpc_arch_ops.save_remote_msgqueue_pa(ch,
+ args->local_msgqueue_pa);
+ if (ret != xpSuccess) {
+ XPC_DISCONNECT_CHANNEL(ch, ret, &irq_flags);
+ goto out;
+ }
+ ch->flags |= XPC_C_ROPENREPLY;
+
+ if (args->local_nentries < ch->remote_nentries) {
+ dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY: new "
+ "remote_nentries=%d, old remote_nentries=%d, "
+ "partid=%d, channel=%d\n",
+ args->local_nentries, ch->remote_nentries,
+ ch->partid, ch->number);
+
+ ch->remote_nentries = args->local_nentries;
+ }
+ if (args->remote_nentries < ch->local_nentries) {
+ dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY: new "
+ "local_nentries=%d, old local_nentries=%d, "
+ "partid=%d, channel=%d\n",
+ args->remote_nentries, ch->local_nentries,
+ ch->partid, ch->number);
+
+ ch->local_nentries = args->remote_nentries;
+ }
+
+ 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);
+}
+
+/*
+ * Attempt to establish a channel connection to a remote partition.
+ */
+static enum xp_retval
+xpc_connect_channel(struct xpc_channel *ch)
+{
+ unsigned long irq_flags;
+ struct xpc_registration *registration = &xpc_registrations[ch->number];
+
+ if (mutex_trylock(®istration->mutex) == 0)
+ return xpRetry;
+
+ if (!XPC_CHANNEL_REGISTERED(ch->number)) {
+ mutex_unlock(®istration->mutex);
+ return xpUnregistered;
+ }
+
+ spin_lock_irqsave(&ch->lock, irq_flags);
+
+ DBUG_ON(ch->flags & XPC_C_CONNECTED);
+ DBUG_ON(ch->flags & XPC_C_OPENREQUEST);
+
+ if (ch->flags & XPC_C_DISCONNECTING) {
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ mutex_unlock(®istration->mutex);
+ return ch->reason;
+ }
+
+ /* add info from the channel connect registration to the channel */
+
+ ch->kthreads_assigned_limit = registration->assigned_limit;
+ ch->kthreads_idle_limit = registration->idle_limit;
+ DBUG_ON(atomic_read(&ch->kthreads_assigned) != 0);
+ DBUG_ON(atomic_read(&ch->kthreads_idle) != 0);
+ DBUG_ON(atomic_read(&ch->kthreads_active) != 0);
+
+ ch->func = registration->func;
+ DBUG_ON(registration->func == NULL);
+ ch->key = registration->key;
+
+ ch->local_nentries = registration->nentries;
+
+ if (ch->flags & XPC_C_ROPENREQUEST) {
+ if (registration->entry_size != ch->entry_size) {
+ /* the local and remote sides aren't the same */
+
+ /*
+ * Because XPC_DISCONNECT_CHANNEL() can block we're
+ * forced to up the registration sema before we unlock
+ * the channel lock. But that's okay here because we're
+ * done with the part that required the registration
+ * sema. XPC_DISCONNECT_CHANNEL() requires that the
+ * channel lock be locked and will unlock and relock
+ * the channel lock as needed.
+ */
+ mutex_unlock(®istration->mutex);
+ XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,
+ &irq_flags);
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ return xpUnequalMsgSizes;
+ }
+ } else {
+ ch->entry_size = registration->entry_size;
+
+ XPC_SET_REASON(ch, 0, 0);
+ ch->flags &= ~XPC_C_DISCONNECTED;
+
+ atomic_inc(&xpc_partitions[ch->partid].nchannels_active);
+ }
+
+ mutex_unlock(®istration->mutex);
+
+ /* initiate the connection */
+
+ ch->flags |= (XPC_C_OPENREQUEST | XPC_C_CONNECTING);
+ xpc_arch_ops.send_chctl_openrequest(ch, &irq_flags);
+
+ xpc_process_connect(ch, &irq_flags);
+
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+
+ return xpSuccess;
+}
+
+void
+xpc_process_sent_chctl_flags(struct xpc_partition *part)
+{
+ unsigned long irq_flags;
+ union xpc_channel_ctl_flags chctl;
+ struct xpc_channel *ch;
+ int ch_number;
+ u32 ch_flags;
+
+ chctl.all_flags = xpc_arch_ops.get_chctl_all_flags(part);
+
+ /*
+ * Initiate channel connections for registered channels.
+ *
+ * For each connected channel that has pending messages activate idle
+ * kthreads and/or create new kthreads as needed.
+ */
+
+ for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
+ ch = &part->channels[ch_number];
+
+ /*
+ * Process any open or close related chctl flags, and then deal
+ * with connecting or disconnecting the channel as required.
+ */
+
+ if (chctl.flags[ch_number] & XPC_OPENCLOSE_CHCTL_FLAGS) {
+ xpc_process_openclose_chctl_flags(part, ch_number,
+ chctl.flags[ch_number]);
+ }
+
+ ch_flags = ch->flags; /* need an atomic snapshot of flags */
+
+ if (ch_flags & XPC_C_DISCONNECTING) {
+ spin_lock_irqsave(&ch->lock, irq_flags);
+ xpc_process_disconnect(ch, &irq_flags);
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ continue;
+ }
+
+ if (part->act_state == XPC_P_AS_DEACTIVATING)
+ continue;
+
+ if (!(ch_flags & XPC_C_CONNECTED)) {
+ if (!(ch_flags & XPC_C_OPENREQUEST)) {
+ DBUG_ON(ch_flags & XPC_C_SETUP);
+ (void)xpc_connect_channel(ch);
+ }
+ continue;
+ }
+
+ /*
+ * Process any message related chctl flags, this may involve
+ * the activation of kthreads to deliver any pending messages
+ * sent from the other partition.
+ */
+
+ if (chctl.flags[ch_number] & XPC_MSG_CHCTL_FLAGS)
+ xpc_arch_ops.process_msg_chctl_flags(part, ch_number);
+ }
+}
+
+/*
+ * XPC's heartbeat code calls this function to inform XPC that a partition is
+ * going down. XPC responds by tearing down the XPartition Communication
+ * infrastructure used for the just downed partition.
+ *
+ * XPC's heartbeat code will never call this function and xpc_partition_up()
+ * at the same time. Nor will it ever make multiple calls to either function
+ * at the same time.
+ */
+void
+xpc_partition_going_down(struct xpc_partition *part, enum xp_retval reason)
+{
+ unsigned long irq_flags;
+ int ch_number;
+ struct xpc_channel *ch;
+
+ dev_dbg(xpc_chan, "deactivating partition %d, reason=%d\n",
+ XPC_PARTID(part), reason);
+
+ if (!xpc_part_ref(part)) {
+ /* infrastructure for this partition isn't currently set up */
+ return;
+ }
+
+ /* disconnect channels associated with the partition going down */
+
+ for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
+ ch = &part->channels[ch_number];
+
+ xpc_msgqueue_ref(ch);
+ spin_lock_irqsave(&ch->lock, irq_flags);
+
+ XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
+
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ xpc_msgqueue_deref(ch);
+ }
+
+ xpc_wakeup_channel_mgr(part);
+
+ xpc_part_deref(part);
+}
+
+/*
+ * Called by XP at the time of channel connection registration to cause
+ * XPC to establish connections to all currently active partitions.
+ */
+void
+xpc_initiate_connect(int ch_number)
+{
+ short partid;
+ struct xpc_partition *part;
+ struct xpc_channel *ch;
+
+ DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
+
+ for (partid = 0; partid < xp_max_npartitions; partid++) {
+ part = &xpc_partitions[partid];
+
+ if (xpc_part_ref(part)) {
+ ch = &part->channels[ch_number];
+
+ /*
+ * Initiate the establishment of a connection on the
+ * newly registered channel to the remote partition.
+ */
+ xpc_wakeup_channel_mgr(part);
+ xpc_part_deref(part);
+ }
+ }
+}
+
+void
+xpc_connected_callout(struct xpc_channel *ch)
+{
+ /* let the registerer know that a connection has been established */
+
+ if (ch->func != NULL) {
+ dev_dbg(xpc_chan, "ch->func() called, reason=xpConnected, "
+ "partid=%d, channel=%d\n", ch->partid, ch->number);
+
+ ch->func(xpConnected, ch->partid, ch->number,
+ (void *)(u64)ch->local_nentries, ch->key);
+
+ dev_dbg(xpc_chan, "ch->func() returned, reason=xpConnected, "
+ "partid=%d, channel=%d\n", ch->partid, ch->number);
+ }
+}
+
+/*
+ * Called by XP at the time of channel connection unregistration to cause
+ * XPC to teardown all current connections for the specified channel.
+ *
+ * Before returning xpc_initiate_disconnect() will wait until all connections
+ * on the specified channel have been closed/torndown. So the caller can be
+ * assured that they will not be receiving any more callouts from XPC to the
+ * function they registered via xpc_connect().
+ *
+ * Arguments:
+ *
+ * ch_number - channel # to unregister.
+ */
+void
+xpc_initiate_disconnect(int ch_number)
+{
+ unsigned long irq_flags;
+ short partid;
+ struct xpc_partition *part;
+ struct xpc_channel *ch;
+
+ DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
+
+ /* initiate the channel disconnect for every active partition */
+ for (partid = 0; partid < xp_max_npartitions; partid++) {
+ part = &xpc_partitions[partid];
+
+ if (xpc_part_ref(part)) {
+ ch = &part->channels[ch_number];
+ xpc_msgqueue_ref(ch);
+
+ spin_lock_irqsave(&ch->lock, irq_flags);
+
+ if (!(ch->flags & XPC_C_DISCONNECTED)) {
+ ch->flags |= XPC_C_WDISCONNECT;
+
+ XPC_DISCONNECT_CHANNEL(ch, xpUnregistering,
+ &irq_flags);
+ }
+
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+
+ xpc_msgqueue_deref(ch);
+ xpc_part_deref(part);
+ }
+ }
+
+ xpc_disconnect_wait(ch_number);
+}
+
+/*
+ * To disconnect a channel, and reflect it back to all who may be waiting.
+ *
+ * An OPEN is not allowed until XPC_C_DISCONNECTING is cleared by
+ * xpc_process_disconnect(), and if set, XPC_C_WDISCONNECT is cleared by
+ * xpc_disconnect_wait().
+ *
+ * THE CHANNEL IS TO BE LOCKED BY THE CALLER AND WILL REMAIN LOCKED UPON RETURN.
+ */
+void
+xpc_disconnect_channel(const int line, struct xpc_channel *ch,
+ enum xp_retval reason, unsigned long *irq_flags)
+{
+ u32 channel_was_connected = (ch->flags & XPC_C_CONNECTED);
+
+ DBUG_ON(!spin_is_locked(&ch->lock));
+
+ if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
+ return;
+
+ DBUG_ON(!(ch->flags & (XPC_C_CONNECTING | XPC_C_CONNECTED)));
+
+ dev_dbg(xpc_chan, "reason=%d, line=%d, partid=%d, channel=%d\n",
+ reason, line, ch->partid, ch->number);
+
+ XPC_SET_REASON(ch, reason, line);
+
+ ch->flags |= (XPC_C_CLOSEREQUEST | XPC_C_DISCONNECTING);
+ /* some of these may not have been set */
+ ch->flags &= ~(XPC_C_OPENREQUEST | XPC_C_OPENREPLY |
+ XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |
+ XPC_C_CONNECTING | XPC_C_CONNECTED);
+
+ xpc_arch_ops.send_chctl_closerequest(ch, irq_flags);
+
+ if (channel_was_connected)
+ ch->flags |= XPC_C_WASCONNECTED;
+
+ spin_unlock_irqrestore(&ch->lock, *irq_flags);
+
+ /* wake all idle kthreads so they can exit */
+ if (atomic_read(&ch->kthreads_idle) > 0) {
+ wake_up_all(&ch->idle_wq);
+
+ } else if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
+ !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
+ /* start a kthread that will do the xpDisconnecting callout */
+ xpc_create_kthreads(ch, 1, 1);
+ }
+
+ /* wake those waiting to allocate an entry from the local msg queue */
+ if (atomic_read(&ch->n_on_msg_allocate_wq) > 0)
+ wake_up(&ch->msg_allocate_wq);
+
+ spin_lock_irqsave(&ch->lock, *irq_flags);
+}
+
+void
+xpc_disconnect_callout(struct xpc_channel *ch, enum xp_retval reason)
+{
+ /*
+ * Let the channel's registerer know that the channel is being
+ * disconnected. We don't want to do this if the registerer was never
+ * informed of a connection being made.
+ */
+
+ if (ch->func != NULL) {
+ dev_dbg(xpc_chan, "ch->func() called, reason=%d, partid=%d, "
+ "channel=%d\n", reason, ch->partid, ch->number);
+
+ ch->func(reason, ch->partid, ch->number, NULL, ch->key);
+
+ dev_dbg(xpc_chan, "ch->func() returned, reason=%d, partid=%d, "
+ "channel=%d\n", reason, ch->partid, ch->number);
+ }
+}
+
+/*
+ * Wait for a message entry to become available for the specified channel,
+ * but don't wait any longer than 1 jiffy.
+ */
+enum xp_retval
+xpc_allocate_msg_wait(struct xpc_channel *ch)
+{
+ enum xp_retval ret;
+ DEFINE_WAIT(wait);
+
+ if (ch->flags & XPC_C_DISCONNECTING) {
+ DBUG_ON(ch->reason == xpInterrupted);
+ return ch->reason;
+ }
+
+ atomic_inc(&ch->n_on_msg_allocate_wq);
+ prepare_to_wait(&ch->msg_allocate_wq, &wait, TASK_INTERRUPTIBLE);
+ ret = schedule_timeout(1);
+ finish_wait(&ch->msg_allocate_wq, &wait);
+ atomic_dec(&ch->n_on_msg_allocate_wq);
+
+ if (ch->flags & XPC_C_DISCONNECTING) {
+ ret = ch->reason;
+ DBUG_ON(ch->reason == xpInterrupted);
+ } else if (ret == 0) {
+ ret = xpTimeout;
+ } else {
+ ret = xpInterrupted;
+ }
+
+ return ret;
+}
+
+/*
+ * Send a message that contains the user's payload on the specified channel
+ * connected to the specified partition.
+ *
+ * NOTE that this routine can sleep waiting for a message entry to become
+ * available. To not sleep, pass in the XPC_NOWAIT flag.
+ *
+ * Once sent, this routine will not wait for the message to be received, nor
+ * will notification be given when it does happen.
+ *
+ * Arguments:
+ *
+ * partid - ID of partition to which the channel is connected.
+ * ch_number - channel # to send message on.
+ * flags - see xp.h for valid flags.
+ * payload - pointer to the payload which is to be sent.
+ * payload_size - size of the payload in bytes.
+ */
+enum xp_retval
+xpc_initiate_send(short partid, int ch_number, u32 flags, void *payload,
+ u16 payload_size)
+{
+ struct xpc_partition *part = &xpc_partitions[partid];
+ enum xp_retval ret = xpUnknownReason;
+
+ dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,
+ partid, ch_number);
+
+ DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
+ DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
+ DBUG_ON(payload == NULL);
+
+ if (xpc_part_ref(part)) {
+ ret = xpc_arch_ops.send_payload(&part->channels[ch_number],
+ flags, payload, payload_size, 0, NULL, NULL);
+ xpc_part_deref(part);
+ }
+
+ return ret;
+}
+
+/*
+ * Send a message that contains the user's payload on the specified channel
+ * connected to the specified partition.
+ *
+ * NOTE that this routine can sleep waiting for a message entry to become
+ * available. To not sleep, pass in the XPC_NOWAIT flag.
+ *
+ * This routine will not wait for the message to be sent or received.
+ *
+ * Once the remote end of the channel has received the message, the function
+ * passed as an argument to xpc_initiate_send_notify() will be called. This
+ * allows the sender to free up or re-use any buffers referenced by the
+ * message, but does NOT mean the message has been processed at the remote
+ * end by a receiver.
+ *
+ * If this routine returns an error, the caller's function will NOT be called.
+ *
+ * Arguments:
+ *
+ * partid - ID of partition to which the channel is connected.
+ * ch_number - channel # to send message on.
+ * flags - see xp.h for valid flags.
+ * payload - pointer to the payload which is to be sent.
+ * payload_size - size of the payload in bytes.
+ * func - function to call with asynchronous notification of message
+ * receipt. THIS FUNCTION MUST BE NON-BLOCKING.
+ * key - user-defined key to be passed to the function when it's called.
+ */
+enum xp_retval
+xpc_initiate_send_notify(short partid, int ch_number, u32 flags, void *payload,
+ u16 payload_size, xpc_notify_func func, void *key)
+{
+ struct xpc_partition *part = &xpc_partitions[partid];
+ enum xp_retval ret = xpUnknownReason;
+
+ dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,
+ partid, ch_number);
+
+ DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
+ DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
+ DBUG_ON(payload == NULL);
+ DBUG_ON(func == NULL);
+
+ if (xpc_part_ref(part)) {
+ ret = xpc_arch_ops.send_payload(&part->channels[ch_number],
+ flags, payload, payload_size, XPC_N_CALL, func, key);
+ xpc_part_deref(part);
+ }
+ return ret;
+}
+
+/*
+ * Deliver a message's payload to its intended recipient.
+ */
+void
+xpc_deliver_payload(struct xpc_channel *ch)
+{
+ void *payload;
+
+ payload = xpc_arch_ops.get_deliverable_payload(ch);
+ if (payload != NULL) {
+
+ /*
+ * This ref is taken to protect the payload itself from being
+ * freed before the user is finished with it, which the user
+ * indicates by calling xpc_initiate_received().
+ */
+ xpc_msgqueue_ref(ch);
+
+ atomic_inc(&ch->kthreads_active);
+
+ if (ch->func != NULL) {
+ dev_dbg(xpc_chan, "ch->func() called, payload=0x%p "
+ "partid=%d channel=%d\n", payload, ch->partid,
+ ch->number);
+
+ /* deliver the message to its intended recipient */
+ ch->func(xpMsgReceived, ch->partid, ch->number, payload,
+ ch->key);
+
+ dev_dbg(xpc_chan, "ch->func() returned, payload=0x%p "
+ "partid=%d channel=%d\n", payload, ch->partid,
+ ch->number);
+ }
+
+ atomic_dec(&ch->kthreads_active);
+ }
+}
+
+/*
+ * Acknowledge receipt of a delivered message's payload.
+ *
+ * This function, although called by users, does not call xpc_part_ref() to
+ * ensure that the partition infrastructure is in place. It relies on the
+ * fact that we called xpc_msgqueue_ref() in xpc_deliver_payload().
+ *
+ * Arguments:
+ *
+ * partid - ID of partition to which the channel is connected.
+ * ch_number - channel # message received on.
+ * payload - pointer to the payload area allocated via
+ * xpc_initiate_send() or xpc_initiate_send_notify().
+ */
+void
+xpc_initiate_received(short partid, int ch_number, void *payload)
+{
+ struct xpc_partition *part = &xpc_partitions[partid];
+ struct xpc_channel *ch;
+
+ DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
+ DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
+
+ ch = &part->channels[ch_number];
+ xpc_arch_ops.received_payload(ch, payload);
+
+ /* the call to xpc_msgqueue_ref() was done by xpc_deliver_payload() */
+ xpc_msgqueue_deref(ch);
+}
Code Review / kvmfornfv.git / blobdiff