linux/drivers/misc/sgi-xp/xpc_channel.c
Arnd Bergmann 11d5ceb646 sgi-xp: open-code interruptible_sleep_on_timeout
interruptible_sleep_on_timeout is deprecated and going away soon.
The use in the sgi-xp driver leaves me puzzled, so I'd prefer not
to touch it. This patch replaces it with an open-coded prepare_to_wait
and finish_wait pair, which should be completely equivalent, so it
doesn't fix an existing race, but lets us get away with removing
the function so we can not get any new users.

In order to remove the typical sleep_on race, one would have to
replace the call with wait_event_interruptible_timeout and add
a condition to wait for. The fact that there is a one-jiffy timeout
suggests that we don't actually expect to get woken up properly
and the caller just uses this as a short sleeping function
if it doesn't wake up properly.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Cliff Whickman <cpw@sgi.com>
Acked-by: Robin Holt <robinmholt@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-08 15:18:02 -08:00

1015 lines
28 KiB
C

/*
* 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(&registration->mutex) == 0)
return xpRetry;
if (!XPC_CHANNEL_REGISTERED(ch->number)) {
mutex_unlock(&registration->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(&registration->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(&registration->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(&registration->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);
}