diff options
Diffstat (limited to 'drivers/misc/sgi-xp/xpc_channel.c')
| -rw-r--r-- | drivers/misc/sgi-xp/xpc_channel.c | 1011 |
1 files changed, 1011 insertions, 0 deletions
diff --git a/drivers/misc/sgi-xp/xpc_channel.c b/drivers/misc/sgi-xp/xpc_channel.c new file mode 100644 index 0000000000..8e6607fc8a --- /dev/null +++ b/drivers/misc/sgi-xp/xpc_channel.c @@ -0,0 +1,1011 @@ +/* + * 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; + + lockdep_assert_held(&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); + + lockdep_assert_held(&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; + + 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)) { + /* + * 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); + + lockdep_assert_held(&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); +} |