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linux/arch/ia64/sn/kernel/xpc_channel.c
Dean Nelson 89eb8eb927 [IA64-SGI] SGI Altix cross partition functionality [2/3] 
This patch contains the communication module (XPC) for cross partition
communication on a partitioned SGI Altix.

Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2005-05-03 12:36:00 -07:00

2298 lines
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/*
* 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) 2004-2005 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/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/cache.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <asm/sn/bte.h>
#include <asm/sn/sn_sal.h>
#include "xpc.h"
/*
* Set up the initial values for the XPartition Communication channels.
*/
static void
xpc_initialize_channels(struct xpc_partition *part, partid_t partid)
{
int ch_number;
struct xpc_channel *ch;
for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
ch = &part->channels[ch_number];
ch->partid = partid;
ch->number = ch_number;
ch->flags = XPC_C_DISCONNECTED;
ch->local_GP = &part->local_GPs[ch_number];
ch->local_openclose_args =
&part->local_openclose_args[ch_number];
atomic_set(&ch->kthreads_assigned, 0);
atomic_set(&ch->kthreads_idle, 0);
atomic_set(&ch->kthreads_active, 0);
atomic_set(&ch->references, 0);
atomic_set(&ch->n_to_notify, 0);
spin_lock_init(&ch->lock);
sema_init(&ch->msg_to_pull_sema, 1); /* mutex */
atomic_set(&ch->n_on_msg_allocate_wq, 0);
init_waitqueue_head(&ch->msg_allocate_wq);
init_waitqueue_head(&ch->idle_wq);
}
}
/*
* Setup the infrastructure necessary to support XPartition Communication
* between the specified remote partition and the local one.
*/
enum xpc_retval
xpc_setup_infrastructure(struct xpc_partition *part)
{
int ret;
struct timer_list *timer;
partid_t partid = XPC_PARTID(part);
/*
* Zero out MOST of the entry for this partition. Only the fields
* starting with `nchannels' will be zeroed. The preceding fields must
* remain `viable' across partition ups and downs, since they may be
* referenced during this memset() operation.
*/
memset(&part->nchannels, 0, sizeof(struct xpc_partition) -
offsetof(struct xpc_partition, nchannels));
/*
* Allocate all of the channel structures as a contiguous chunk of
* memory.
*/
part->channels = kmalloc(sizeof(struct xpc_channel) * XPC_NCHANNELS,
GFP_KERNEL);
if (part->channels == NULL) {
dev_err(xpc_chan, "can't get memory for channels\n");
return xpcNoMemory;
}
memset(part->channels, 0, sizeof(struct xpc_channel) * XPC_NCHANNELS);
part->nchannels = XPC_NCHANNELS;
/* allocate all the required GET/PUT values */
part->local_GPs = xpc_kmalloc_cacheline_aligned(XPC_GP_SIZE,
GFP_KERNEL, &part->local_GPs_base);
if (part->local_GPs == NULL) {
kfree(part->channels);
part->channels = NULL;
dev_err(xpc_chan, "can't get memory for local get/put "
"values\n");
return xpcNoMemory;
}
memset(part->local_GPs, 0, XPC_GP_SIZE);
part->remote_GPs = xpc_kmalloc_cacheline_aligned(XPC_GP_SIZE,
GFP_KERNEL, &part->remote_GPs_base);
if (part->remote_GPs == NULL) {
kfree(part->channels);
part->channels = NULL;
kfree(part->local_GPs_base);
part->local_GPs = NULL;
dev_err(xpc_chan, "can't get memory for remote get/put "
"values\n");
return xpcNoMemory;
}
memset(part->remote_GPs, 0, XPC_GP_SIZE);
/* allocate all the required open and close args */
part->local_openclose_args = xpc_kmalloc_cacheline_aligned(
XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL,
&part->local_openclose_args_base);
if (part->local_openclose_args == NULL) {
kfree(part->channels);
part->channels = NULL;
kfree(part->local_GPs_base);
part->local_GPs = NULL;
kfree(part->remote_GPs_base);
part->remote_GPs = NULL;
dev_err(xpc_chan, "can't get memory for local connect args\n");
return xpcNoMemory;
}
memset(part->local_openclose_args, 0, XPC_OPENCLOSE_ARGS_SIZE);
part->remote_openclose_args = xpc_kmalloc_cacheline_aligned(
XPC_OPENCLOSE_ARGS_SIZE, GFP_KERNEL,
&part->remote_openclose_args_base);
if (part->remote_openclose_args == NULL) {
kfree(part->channels);
part->channels = NULL;
kfree(part->local_GPs_base);
part->local_GPs = NULL;
kfree(part->remote_GPs_base);
part->remote_GPs = NULL;
kfree(part->local_openclose_args_base);
part->local_openclose_args = NULL;
dev_err(xpc_chan, "can't get memory for remote connect args\n");
return xpcNoMemory;
}
memset(part->remote_openclose_args, 0, XPC_OPENCLOSE_ARGS_SIZE);
xpc_initialize_channels(part, partid);
atomic_set(&part->nchannels_active, 0);
/* local_IPI_amo were set to 0 by an earlier memset() */
/* Initialize this partitions AMO_t structure */
part->local_IPI_amo_va = xpc_IPI_init(partid);
spin_lock_init(&part->IPI_lock);
atomic_set(&part->channel_mgr_requests, 1);
init_waitqueue_head(&part->channel_mgr_wq);
sprintf(part->IPI_owner, "xpc%02d", partid);
ret = request_irq(SGI_XPC_NOTIFY, xpc_notify_IRQ_handler, SA_SHIRQ,
part->IPI_owner, (void *) (u64) partid);
if (ret != 0) {
kfree(part->channels);
part->channels = NULL;
kfree(part->local_GPs_base);
part->local_GPs = NULL;
kfree(part->remote_GPs_base);
part->remote_GPs = NULL;
kfree(part->local_openclose_args_base);
part->local_openclose_args = NULL;
kfree(part->remote_openclose_args_base);
part->remote_openclose_args = NULL;
dev_err(xpc_chan, "can't register NOTIFY IRQ handler, "
"errno=%d\n", -ret);
return xpcLackOfResources;
}
/* Setup a timer to check for dropped IPIs */
timer = &part->dropped_IPI_timer;
init_timer(timer);
timer->function = (void (*)(unsigned long)) xpc_dropped_IPI_check;
timer->data = (unsigned long) part;
timer->expires = jiffies + XPC_P_DROPPED_IPI_WAIT;
add_timer(timer);
/*
* With the setting of the partition setup_state to XPC_P_SETUP, we're
* declaring that this partition is ready to go.
*/
(volatile u8) part->setup_state = XPC_P_SETUP;
/*
* Setup the per partition specific variables required by the
* remote partition to establish channel connections with us.
*
* The setting of the magic # indicates that these per partition
* specific variables are ready to be used.
*/
xpc_vars_part[partid].GPs_pa = __pa(part->local_GPs);
xpc_vars_part[partid].openclose_args_pa =
__pa(part->local_openclose_args);
xpc_vars_part[partid].IPI_amo_pa = __pa(part->local_IPI_amo_va);
xpc_vars_part[partid].IPI_nasid = cpuid_to_nasid(smp_processor_id());
xpc_vars_part[partid].IPI_phys_cpuid =
cpu_physical_id(smp_processor_id());
xpc_vars_part[partid].nchannels = part->nchannels;
(volatile u64) xpc_vars_part[partid].magic = XPC_VP_MAGIC1;
return xpcSuccess;
}
/*
* Create a wrapper that hides the underlying mechanism for pulling a cacheline
* (or multiple cachelines) from a remote partition.
*
* src must be a cacheline aligned physical address on the remote partition.
* dst must be a cacheline aligned virtual address on this partition.
* cnt must be an cacheline sized
*/
static enum xpc_retval
xpc_pull_remote_cachelines(struct xpc_partition *part, void *dst,
const void *src, size_t cnt)
{
bte_result_t bte_ret;
DBUG_ON((u64) src != L1_CACHE_ALIGN((u64) src));
DBUG_ON((u64) dst != L1_CACHE_ALIGN((u64) dst));
DBUG_ON(cnt != L1_CACHE_ALIGN(cnt));
if (part->act_state == XPC_P_DEACTIVATING) {
return part->reason;
}
bte_ret = xp_bte_copy((u64) src, (u64) ia64_tpa((u64) dst),
(u64) cnt, (BTE_NORMAL | BTE_WACQUIRE), NULL);
if (bte_ret == BTE_SUCCESS) {
return xpcSuccess;
}
dev_dbg(xpc_chan, "xp_bte_copy() from partition %d failed, ret=%d\n",
XPC_PARTID(part), bte_ret);
return xpc_map_bte_errors(bte_ret);
}
/*
* Pull the remote per partititon specific variables from the specified
* partition.
*/
enum xpc_retval
xpc_pull_remote_vars_part(struct xpc_partition *part)
{
u8 buffer[L1_CACHE_BYTES * 2];
struct xpc_vars_part *pulled_entry_cacheline =
(struct xpc_vars_part *) L1_CACHE_ALIGN((u64) buffer);
struct xpc_vars_part *pulled_entry;
u64 remote_entry_cacheline_pa, remote_entry_pa;
partid_t partid = XPC_PARTID(part);
enum xpc_retval ret;
/* pull the cacheline that contains the variables we're interested in */
DBUG_ON(part->remote_vars_part_pa !=
L1_CACHE_ALIGN(part->remote_vars_part_pa));
DBUG_ON(sizeof(struct xpc_vars_part) != L1_CACHE_BYTES / 2);
remote_entry_pa = part->remote_vars_part_pa +
sn_partition_id * sizeof(struct xpc_vars_part);
remote_entry_cacheline_pa = (remote_entry_pa & ~(L1_CACHE_BYTES - 1));
pulled_entry = (struct xpc_vars_part *) ((u64) pulled_entry_cacheline +
(remote_entry_pa & (L1_CACHE_BYTES - 1)));
ret = xpc_pull_remote_cachelines(part, pulled_entry_cacheline,
(void *) remote_entry_cacheline_pa,
L1_CACHE_BYTES);
if (ret != xpcSuccess) {
dev_dbg(xpc_chan, "failed to pull XPC vars_part from "
"partition %d, ret=%d\n", partid, ret);
return ret;
}
/* see if they've been set up yet */
if (pulled_entry->magic != XPC_VP_MAGIC1 &&
pulled_entry->magic != XPC_VP_MAGIC2) {
if (pulled_entry->magic != 0) {
dev_dbg(xpc_chan, "partition %d's XPC vars_part for "
"partition %d has bad magic value (=0x%lx)\n",
partid, sn_partition_id, pulled_entry->magic);
return xpcBadMagic;
}
/* they've not been initialized yet */
return xpcRetry;
}
if (xpc_vars_part[partid].magic == XPC_VP_MAGIC1) {
/* validate the variables */
if (pulled_entry->GPs_pa == 0 ||
pulled_entry->openclose_args_pa == 0 ||
pulled_entry->IPI_amo_pa == 0) {
dev_err(xpc_chan, "partition %d's XPC vars_part for "
"partition %d are not valid\n", partid,
sn_partition_id);
return xpcInvalidAddress;
}
/* the variables we imported look to be valid */
part->remote_GPs_pa = pulled_entry->GPs_pa;
part->remote_openclose_args_pa =
pulled_entry->openclose_args_pa;
part->remote_IPI_amo_va =
(AMO_t *) __va(pulled_entry->IPI_amo_pa);
part->remote_IPI_nasid = pulled_entry->IPI_nasid;
part->remote_IPI_phys_cpuid = pulled_entry->IPI_phys_cpuid;
if (part->nchannels > pulled_entry->nchannels) {
part->nchannels = pulled_entry->nchannels;
}
/* let the other side know that we've pulled their variables */
(volatile u64) xpc_vars_part[partid].magic = XPC_VP_MAGIC2;
}
if (pulled_entry->magic == XPC_VP_MAGIC1) {
return xpcRetry;
}
return xpcSuccess;
}
/*
* Get the IPI flags and pull the openclose args and/or remote GPs as needed.
*/
static u64
xpc_get_IPI_flags(struct xpc_partition *part)
{
unsigned long irq_flags;
u64 IPI_amo;
enum xpc_retval ret;
/*
* See if there are any IPI flags to be handled.
*/
spin_lock_irqsave(&part->IPI_lock, irq_flags);
if ((IPI_amo = part->local_IPI_amo) != 0) {
part->local_IPI_amo = 0;
}
spin_unlock_irqrestore(&part->IPI_lock, irq_flags);
if (XPC_ANY_OPENCLOSE_IPI_FLAGS_SET(IPI_amo)) {
ret = xpc_pull_remote_cachelines(part,
part->remote_openclose_args,
(void *) part->remote_openclose_args_pa,
XPC_OPENCLOSE_ARGS_SIZE);
if (ret != xpcSuccess) {
XPC_DEACTIVATE_PARTITION(part, ret);
dev_dbg(xpc_chan, "failed to pull openclose args from "
"partition %d, ret=%d\n", XPC_PARTID(part),
ret);
/* don't bother processing IPIs anymore */
IPI_amo = 0;
}
}
if (XPC_ANY_MSG_IPI_FLAGS_SET(IPI_amo)) {
ret = xpc_pull_remote_cachelines(part, part->remote_GPs,
(void *) part->remote_GPs_pa,
XPC_GP_SIZE);
if (ret != xpcSuccess) {
XPC_DEACTIVATE_PARTITION(part, ret);
dev_dbg(xpc_chan, "failed to pull GPs from partition "
"%d, ret=%d\n", XPC_PARTID(part), ret);
/* don't bother processing IPIs anymore */
IPI_amo = 0;
}
}
return IPI_amo;
}
/*
* Allocate the local message queue and the notify queue.
*/
static enum xpc_retval
xpc_allocate_local_msgqueue(struct xpc_channel *ch)
{
unsigned long irq_flags;
int nentries;
size_t nbytes;
// >>> may want to check for ch->flags & XPC_C_DISCONNECTING between
// >>> iterations of the for-loop, bail if set?
// >>> should we impose a minumum #of entries? like 4 or 8?
for (nentries = ch->local_nentries; nentries > 0; nentries--) {
nbytes = nentries * ch->msg_size;
ch->local_msgqueue = xpc_kmalloc_cacheline_aligned(nbytes,
(GFP_KERNEL | GFP_DMA),
&ch->local_msgqueue_base);
if (ch->local_msgqueue == NULL) {
continue;
}
memset(ch->local_msgqueue, 0, nbytes);
nbytes = nentries * sizeof(struct xpc_notify);
ch->notify_queue = kmalloc(nbytes, (GFP_KERNEL | GFP_DMA));
if (ch->notify_queue == NULL) {
kfree(ch->local_msgqueue_base);
ch->local_msgqueue = NULL;
continue;
}
memset(ch->notify_queue, 0, nbytes);
spin_lock_irqsave(&ch->lock, irq_flags);
if (nentries < ch->local_nentries) {
dev_dbg(xpc_chan, "nentries=%d local_nentries=%d, "
"partid=%d, channel=%d\n", nentries,
ch->local_nentries, ch->partid, ch->number);
ch->local_nentries = nentries;
}
spin_unlock_irqrestore(&ch->lock, irq_flags);
return xpcSuccess;
}
dev_dbg(xpc_chan, "can't get memory for local message queue and notify "
"queue, partid=%d, channel=%d\n", ch->partid, ch->number);
return xpcNoMemory;
}
/*
* Allocate the cached remote message queue.
*/
static enum xpc_retval
xpc_allocate_remote_msgqueue(struct xpc_channel *ch)
{
unsigned long irq_flags;
int nentries;
size_t nbytes;
DBUG_ON(ch->remote_nentries <= 0);
// >>> may want to check for ch->flags & XPC_C_DISCONNECTING between
// >>> iterations of the for-loop, bail if set?
// >>> should we impose a minumum #of entries? like 4 or 8?
for (nentries = ch->remote_nentries; nentries > 0; nentries--) {
nbytes = nentries * ch->msg_size;
ch->remote_msgqueue = xpc_kmalloc_cacheline_aligned(nbytes,
(GFP_KERNEL | GFP_DMA),
&ch->remote_msgqueue_base);
if (ch->remote_msgqueue == NULL) {
continue;
}
memset(ch->remote_msgqueue, 0, nbytes);
spin_lock_irqsave(&ch->lock, irq_flags);
if (nentries < ch->remote_nentries) {
dev_dbg(xpc_chan, "nentries=%d remote_nentries=%d, "
"partid=%d, channel=%d\n", nentries,
ch->remote_nentries, ch->partid, ch->number);
ch->remote_nentries = nentries;
}
spin_unlock_irqrestore(&ch->lock, irq_flags);
return xpcSuccess;
}
dev_dbg(xpc_chan, "can't get memory for cached remote message queue, "
"partid=%d, channel=%d\n", ch->partid, ch->number);
return xpcNoMemory;
}
/*
* Allocate message queues and other stuff associated with a channel.
*
* Note: Assumes all of the channel sizes are filled in.
*/
static enum xpc_retval
xpc_allocate_msgqueues(struct xpc_channel *ch)
{
unsigned long irq_flags;
int i;
enum xpc_retval ret;
DBUG_ON(ch->flags & XPC_C_SETUP);
if ((ret = xpc_allocate_local_msgqueue(ch)) != xpcSuccess) {
return ret;
}
if ((ret = xpc_allocate_remote_msgqueue(ch)) != xpcSuccess) {
kfree(ch->local_msgqueue_base);
ch->local_msgqueue = NULL;
kfree(ch->notify_queue);
ch->notify_queue = NULL;
return ret;
}
for (i = 0; i < ch->local_nentries; i++) {
/* use a semaphore as an event wait queue */
sema_init(&ch->notify_queue[i].sema, 0);
}
sema_init(&ch->teardown_sema, 0); /* event wait */
spin_lock_irqsave(&ch->lock, irq_flags);
ch->flags |= XPC_C_SETUP;
spin_unlock_irqrestore(&ch->lock, irq_flags);
return xpcSuccess;
}
/*
* 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 xpc_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_allocate_msgqueues(ch);
spin_lock_irqsave(&ch->lock, *irq_flags);
if (ret != xpcSuccess) {
XPC_DISCONNECT_CHANNEL(ch, ret, irq_flags);
}
if (ch->flags & (XPC_C_CONNECTED | XPC_C_DISCONNECTING)) {
return;
}
DBUG_ON(!(ch->flags & XPC_C_SETUP));
DBUG_ON(ch->local_msgqueue == NULL);
DBUG_ON(ch->remote_msgqueue == NULL);
}
if (!(ch->flags & XPC_C_OPENREPLY)) {
ch->flags |= XPC_C_OPENREPLY;
xpc_IPI_send_openreply(ch, irq_flags);
}
if (!(ch->flags & XPC_C_ROPENREPLY)) {
return;
}
DBUG_ON(ch->remote_msgqueue_pa == 0);
ch->flags = (XPC_C_CONNECTED | XPC_C_SETUP); /* clear all else */
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);
spin_lock_irqsave(&ch->lock, *irq_flags);
}
/*
* Free up message queues and other stuff that were allocated for the specified
* channel.
*
* Note: ch->reason and ch->reason_line are left set for debugging purposes,
* they're cleared when XPC_C_DISCONNECTED is cleared.
*/
static void
xpc_free_msgqueues(struct xpc_channel *ch)
{
DBUG_ON(!spin_is_locked(&ch->lock));
DBUG_ON(atomic_read(&ch->n_to_notify) != 0);
ch->remote_msgqueue_pa = 0;
ch->func = NULL;
ch->key = NULL;
ch->msg_size = 0;
ch->local_nentries = 0;
ch->remote_nentries = 0;
ch->kthreads_assigned_limit = 0;
ch->kthreads_idle_limit = 0;
ch->local_GP->get = 0;
ch->local_GP->put = 0;
ch->remote_GP.get = 0;
ch->remote_GP.put = 0;
ch->w_local_GP.get = 0;
ch->w_local_GP.put = 0;
ch->w_remote_GP.get = 0;
ch->w_remote_GP.put = 0;
ch->next_msg_to_pull = 0;
if (ch->flags & XPC_C_SETUP) {
ch->flags &= ~XPC_C_SETUP;
dev_dbg(xpc_chan, "ch->flags=0x%x, partid=%d, channel=%d\n",
ch->flags, ch->partid, ch->number);
kfree(ch->local_msgqueue_base);
ch->local_msgqueue = NULL;
kfree(ch->remote_msgqueue_base);
ch->remote_msgqueue = NULL;
kfree(ch->notify_queue);
ch->notify_queue = NULL;
/* in case someone is waiting for the teardown to complete */
up(&ch->teardown_sema);
}
}
/*
* 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 ch_flags = ch->flags;
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->references) > 0) {
return;
}
DBUG_ON(atomic_read(&ch->kthreads_assigned) != 0);
/* it's now safe to free the channel's message queues */
xpc_free_msgqueues(ch);
DBUG_ON(ch->flags & XPC_C_SETUP);
if (part->act_state != XPC_P_DEACTIVATING) {
/* 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_IPI_send_closereply(ch, irq_flags);
}
if (!(ch->flags & XPC_C_RCLOSEREPLY)) {
return;
}
}
/* both sides are disconnected now */
ch->flags = XPC_C_DISCONNECTED; /* clear all flags, but this one */
atomic_dec(&part->nchannels_active);
if (ch_flags & XPC_C_WASCONNECTED) {
dev_info(xpc_chan, "channel %d to partition %d disconnected, "
"reason=%d\n", ch->number, ch->partid, ch->reason);
}
}
/*
* Process a change in the channel's remote connection state.
*/
static void
xpc_process_openclose_IPI(struct xpc_partition *part, int ch_number,
u8 IPI_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 xpc_retval reason;
spin_lock_irqsave(&ch->lock, irq_flags);
if (IPI_flags & XPC_IPI_CLOSEREQUEST) {
dev_dbg(xpc_chan, "XPC_IPI_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 RCLOSEQREUQEST in the IPI_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(!(IPI_flags & XPC_IPI_CLOSEREPLY));
IPI_flags &= ~XPC_IPI_CLOSEREPLY;
ch->flags |= XPC_C_RCLOSEREPLY;
/* both sides have finished disconnecting */
xpc_process_disconnect(ch, &irq_flags);
}
if (ch->flags & XPC_C_DISCONNECTED) {
// >>> explain this section
if (!(IPI_flags & XPC_IPI_OPENREQUEST)) {
DBUG_ON(part->act_state !=
XPC_P_DEACTIVATING);
spin_unlock_irqrestore(&ch->lock, irq_flags);
return;
}
XPC_SET_REASON(ch, 0, 0);
ch->flags &= ~XPC_C_DISCONNECTED;
atomic_inc(&part->nchannels_active);
ch->flags |= (XPC_C_CONNECTING | XPC_C_ROPENREQUEST);
}
IPI_flags &= ~(XPC_IPI_OPENREQUEST | XPC_IPI_OPENREPLY);
/*
* 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 <= xpcSuccess || reason > xpcUnknownReason) {
reason = xpcUnknownReason;
} else if (reason == xpcUnregistering) {
reason = xpcOtherUnregistering;
}
XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
} else {
xpc_process_disconnect(ch, &irq_flags);
}
}
if (IPI_flags & XPC_IPI_CLOSEREPLY) {
dev_dbg(xpc_chan, "XPC_IPI_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_DEACTIVATING);
spin_unlock_irqrestore(&ch->lock, irq_flags);
return;
}
DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
DBUG_ON(!(ch->flags & XPC_C_RCLOSEREQUEST));
ch->flags |= XPC_C_RCLOSEREPLY;
if (ch->flags & XPC_C_CLOSEREPLY) {
/* both sides have finished disconnecting */
xpc_process_disconnect(ch, &irq_flags);
}
}
if (IPI_flags & XPC_IPI_OPENREQUEST) {
dev_dbg(xpc_chan, "XPC_IPI_OPENREQUEST (msg_size=%d, "
"local_nentries=%d) received from partid=%d, "
"channel=%d\n", args->msg_size, args->local_nentries,
ch->partid, ch->number);
if ((ch->flags & XPC_C_DISCONNECTING) ||
part->act_state == XPC_P_DEACTIVATING) {
spin_unlock_irqrestore(&ch->lock, irq_flags);
return;
}
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:
* msg_size = size of channel's messages in bytes
* local_nentries = remote partition's local_nentries
*/
DBUG_ON(args->msg_size == 0);
DBUG_ON(args->local_nentries == 0);
ch->flags |= (XPC_C_ROPENREQUEST | XPC_C_CONNECTING);
ch->remote_nentries = args->local_nentries;
if (ch->flags & XPC_C_OPENREQUEST) {
if (args->msg_size != ch->msg_size) {
XPC_DISCONNECT_CHANNEL(ch, xpcUnequalMsgSizes,
&irq_flags);
spin_unlock_irqrestore(&ch->lock, irq_flags);
return;
}
} else {
ch->msg_size = args->msg_size;
XPC_SET_REASON(ch, 0, 0);
ch->flags &= ~XPC_C_DISCONNECTED;
atomic_inc(&part->nchannels_active);
}
xpc_process_connect(ch, &irq_flags);
}
if (IPI_flags & XPC_IPI_OPENREPLY) {
dev_dbg(xpc_chan, "XPC_IPI_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)) {
spin_unlock_irqrestore(&ch->lock, irq_flags);
return;
}
DBUG_ON(!(ch->flags & XPC_C_OPENREQUEST));
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);
ch->flags |= XPC_C_ROPENREPLY;
ch->remote_msgqueue_pa = args->local_msgqueue_pa;
if (args->local_nentries < ch->remote_nentries) {
dev_dbg(xpc_chan, "XPC_IPI_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_IPI_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);
}
spin_unlock_irqrestore(&ch->lock, irq_flags);
}
/*
* Attempt to establish a channel connection to a remote partition.
*/
static enum xpc_retval
xpc_connect_channel(struct xpc_channel *ch)
{
unsigned long irq_flags;
struct xpc_registration *registration = &xpc_registrations[ch->number];
if (down_interruptible(&registration->sema) != 0) {
return xpcInterrupted;
}
if (!XPC_CHANNEL_REGISTERED(ch->number)) {
up(&registration->sema);
return xpcUnregistered;
}
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);
up(&registration->sema);
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->msg_size != ch->msg_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.
*/
up(&registration->sema);
XPC_DISCONNECT_CHANNEL(ch, xpcUnequalMsgSizes,
&irq_flags);
spin_unlock_irqrestore(&ch->lock, irq_flags);
return xpcUnequalMsgSizes;
}
} else {
ch->msg_size = registration->msg_size;
XPC_SET_REASON(ch, 0, 0);
ch->flags &= ~XPC_C_DISCONNECTED;
atomic_inc(&xpc_partitions[ch->partid].nchannels_active);
}
up(&registration->sema);
/* initiate the connection */
ch->flags |= (XPC_C_OPENREQUEST | XPC_C_CONNECTING);
xpc_IPI_send_openrequest(ch, &irq_flags);
xpc_process_connect(ch, &irq_flags);
spin_unlock_irqrestore(&ch->lock, irq_flags);
return xpcSuccess;
}
/*
* Notify those who wanted to be notified upon delivery of their message.
*/
static void
xpc_notify_senders(struct xpc_channel *ch, enum xpc_retval reason, s64 put)
{
struct xpc_notify *notify;
u8 notify_type;
s64 get = ch->w_remote_GP.get - 1;
while (++get < put && atomic_read(&ch->n_to_notify) > 0) {
notify = &ch->notify_queue[get % ch->local_nentries];
/*
* See if the notify entry indicates it was associated with
* a message who's sender wants to be notified. It is possible
* that it is, but someone else is doing or has done the
* notification.
*/
notify_type = notify->type;
if (notify_type == 0 ||
cmpxchg(&notify->type, notify_type, 0) !=
notify_type) {
continue;
}
DBUG_ON(notify_type != XPC_N_CALL);
atomic_dec(&ch->n_to_notify);
if (notify->func != NULL) {
dev_dbg(xpc_chan, "notify->func() called, notify=0x%p, "
"msg_number=%ld, partid=%d, channel=%d\n",
(void *) notify, get, ch->partid, ch->number);
notify->func(reason, ch->partid, ch->number,
notify->key);
dev_dbg(xpc_chan, "notify->func() returned, "
"notify=0x%p, msg_number=%ld, partid=%d, "
"channel=%d\n", (void *) notify, get,
ch->partid, ch->number);
}
}
}
/*
* Clear some of the msg flags in the local message queue.
*/
static inline void
xpc_clear_local_msgqueue_flags(struct xpc_channel *ch)
{
struct xpc_msg *msg;
s64 get;
get = ch->w_remote_GP.get;
do {
msg = (struct xpc_msg *) ((u64) ch->local_msgqueue +
(get % ch->local_nentries) * ch->msg_size);
msg->flags = 0;
} while (++get < (volatile s64) ch->remote_GP.get);
}
/*
* Clear some of the msg flags in the remote message queue.
*/
static inline void
xpc_clear_remote_msgqueue_flags(struct xpc_channel *ch)
{
struct xpc_msg *msg;
s64 put;
put = ch->w_remote_GP.put;
do {
msg = (struct xpc_msg *) ((u64) ch->remote_msgqueue +
(put % ch->remote_nentries) * ch->msg_size);
msg->flags = 0;
} while (++put < (volatile s64) ch->remote_GP.put);
}
static void
xpc_process_msg_IPI(struct xpc_partition *part, int ch_number)
{
struct xpc_channel *ch = &part->channels[ch_number];
int nmsgs_sent;
ch->remote_GP = part->remote_GPs[ch_number];
/* See what, if anything, has changed for each connected channel */
xpc_msgqueue_ref(ch);
if (ch->w_remote_GP.get == ch->remote_GP.get &&
ch->w_remote_GP.put == ch->remote_GP.put) {
/* nothing changed since GPs were last pulled */
xpc_msgqueue_deref(ch);
return;
}
if (!(ch->flags & XPC_C_CONNECTED)){
xpc_msgqueue_deref(ch);
return;
}
/*
* First check to see if messages recently sent by us have been
* received by the other side. (The remote GET value will have
* changed since we last looked at it.)
*/
if (ch->w_remote_GP.get != ch->remote_GP.get) {
/*
* We need to notify any senders that want to be notified
* that their sent messages have been received by their
* intended recipients. We need to do this before updating
* w_remote_GP.get so that we don't allocate the same message
* queue entries prematurely (see xpc_allocate_msg()).
*/
if (atomic_read(&ch->n_to_notify) > 0) {
/*
* Notify senders that messages sent have been
* received and delivered by the other side.
*/
xpc_notify_senders(ch, xpcMsgDelivered,
ch->remote_GP.get);
}
/*
* Clear msg->flags in previously sent messages, so that
* they're ready for xpc_allocate_msg().
*/
xpc_clear_local_msgqueue_flags(ch);
(volatile s64) ch->w_remote_GP.get = ch->remote_GP.get;
dev_dbg(xpc_chan, "w_remote_GP.get changed to %ld, partid=%d, "
"channel=%d\n", ch->w_remote_GP.get, ch->partid,
ch->number);
/*
* If anyone was waiting for message queue entries to become
* available, wake them up.
*/
if (atomic_read(&ch->n_on_msg_allocate_wq) > 0) {
wake_up(&ch->msg_allocate_wq);
}
}
/*
* Now check for newly sent messages by the other side. (The remote
* PUT value will have changed since we last looked at it.)
*/
if (ch->w_remote_GP.put != ch->remote_GP.put) {
/*
* Clear msg->flags in previously received messages, so that
* they're ready for xpc_get_deliverable_msg().
*/
xpc_clear_remote_msgqueue_flags(ch);
(volatile s64) ch->w_remote_GP.put = ch->remote_GP.put;
dev_dbg(xpc_chan, "w_remote_GP.put changed to %ld, partid=%d, "
"channel=%d\n", ch->w_remote_GP.put, ch->partid,
ch->number);
nmsgs_sent = ch->w_remote_GP.put - ch->w_local_GP.get;
if (nmsgs_sent > 0) {
dev_dbg(xpc_chan, "msgs waiting to be copied and "
"delivered=%d, partid=%d, channel=%d\n",
nmsgs_sent, ch->partid, ch->number);
if (ch->flags & XPC_C_CONNECTCALLOUT) {
xpc_activate_kthreads(ch, nmsgs_sent);
}
}
}
xpc_msgqueue_deref(ch);
}
void
xpc_process_channel_activity(struct xpc_partition *part)
{
unsigned long irq_flags;
u64 IPI_amo, IPI_flags;
struct xpc_channel *ch;
int ch_number;
IPI_amo = xpc_get_IPI_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 IPI flags, and then deal
* with connecting or disconnecting the channel as required.
*/
IPI_flags = XPC_GET_IPI_FLAGS(IPI_amo, ch_number);
if (XPC_ANY_OPENCLOSE_IPI_FLAGS_SET(IPI_flags)) {
xpc_process_openclose_IPI(part, ch_number, IPI_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_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);
} else {
spin_lock_irqsave(&ch->lock, irq_flags);
xpc_process_connect(ch, &irq_flags);
spin_unlock_irqrestore(&ch->lock, irq_flags);
}
continue;
}
/*
* Process any message related IPI flags, this may involve the
* activation of kthreads to deliver any pending messages sent
* from the other partition.
*/
if (XPC_ANY_MSG_IPI_FLAGS_SET(IPI_flags)) {
xpc_process_msg_IPI(part, ch_number);
}
}
}
/*
* XPC's heartbeat code calls this function to inform XPC that a partition has
* gone 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_down(struct xpc_partition *part, enum xpc_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 all channels associated with the downed partition */
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);
}
/*
* Teardown the infrastructure necessary to support XPartition Communication
* between the specified remote partition and the local one.
*/
void
xpc_teardown_infrastructure(struct xpc_partition *part)
{
partid_t partid = XPC_PARTID(part);
/*
* We start off by making this partition inaccessible to local
* processes by marking it as no longer setup. Then we make it
* inaccessible to remote processes by clearing the XPC per partition
* specific variable's magic # (which indicates that these variables
* are no longer valid) and by ignoring all XPC notify IPIs sent to
* this partition.
*/
DBUG_ON(atomic_read(&part->nchannels_active) != 0);
DBUG_ON(part->setup_state != XPC_P_SETUP);
part->setup_state = XPC_P_WTEARDOWN;
xpc_vars_part[partid].magic = 0;
free_irq(SGI_XPC_NOTIFY, (void *) (u64) partid);
/*
* Before proceding with the teardown we have to wait until all
* existing references cease.
*/
wait_event(part->teardown_wq, (atomic_read(&part->references) == 0));
/* now we can begin tearing down the infrastructure */
part->setup_state = XPC_P_TORNDOWN;
/* in case we've still got outstanding timers registered... */
del_timer_sync(&part->dropped_IPI_timer);
kfree(part->remote_openclose_args_base);
part->remote_openclose_args = NULL;
kfree(part->local_openclose_args_base);
part->local_openclose_args = NULL;
kfree(part->remote_GPs_base);
part->remote_GPs = NULL;
kfree(part->local_GPs_base);
part->local_GPs = NULL;
kfree(part->channels);
part->channels = NULL;
part->local_IPI_amo_va = NULL;
}
/*
* 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)
{
partid_t partid;
struct xpc_partition *part;
struct xpc_channel *ch;
DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS);
for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
part = &xpc_partitions[partid];
if (xpc_part_ref(part)) {
ch = &part->channels[ch_number];
if (!(ch->flags & XPC_C_DISCONNECTING)) {
DBUG_ON(ch->flags & XPC_C_OPENREQUEST);
DBUG_ON(ch->flags & XPC_C_CONNECTED);
DBUG_ON(ch->flags & XPC_C_SETUP);
/*
* 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)
{
unsigned long irq_flags;
/* let the registerer know that a connection has been established */
if (ch->func != NULL) {
dev_dbg(xpc_chan, "ch->func() called, reason=xpcConnected, "
"partid=%d, channel=%d\n", ch->partid, ch->number);
ch->func(xpcConnected, ch->partid, ch->number,
(void *) (u64) ch->local_nentries, ch->key);
dev_dbg(xpc_chan, "ch->func() returned, reason=xpcConnected, "
"partid=%d, channel=%d\n", ch->partid, ch->number);
}
spin_lock_irqsave(&ch->lock, irq_flags);
ch->flags |= XPC_C_CONNECTCALLOUT;
spin_unlock_irqrestore(&ch->lock, irq_flags);
}
/*
* 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;
partid_t partid;
struct xpc_partition *part;
struct xpc_channel *ch;
DBUG_ON(ch_number < 0 || ch_number >= XPC_NCHANNELS);
/* initiate the channel disconnect for every active partition */
for (partid = 1; partid < XP_MAX_PARTITIONS; 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);
XPC_DISCONNECT_CHANNEL(ch, xpcUnregistering,
&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_free_msgqueues().
*
* 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 xpc_retval reason, unsigned long *irq_flags)
{
u32 flags;
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);
flags = ch->flags;
/* 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);
ch->flags |= (XPC_C_CLOSEREQUEST | XPC_C_DISCONNECTING);
xpc_IPI_send_closerequest(ch, irq_flags);
if (flags & XPC_C_CONNECTED) {
ch->flags |= XPC_C_WASCONNECTED;
}
if (atomic_read(&ch->kthreads_idle) > 0) {
/* wake all idle kthreads so they can exit */
wake_up_all(&ch->idle_wq);
}
spin_unlock_irqrestore(&ch->lock, *irq_flags);
/* 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);
}
/* wake those waiting for notify completion */
if (atomic_read(&ch->n_to_notify) > 0) {
xpc_notify_senders(ch, reason, ch->w_local_GP.put);
}
spin_lock_irqsave(&ch->lock, *irq_flags);
}
void
xpc_disconnected_callout(struct xpc_channel *ch)
{
/*
* Let the channel's registerer know that the channel is now
* disconnected. We don't want to do this if the registerer was never
* informed of a connection being made, unless the disconnect was for
* abnormal reasons.
*/
if (ch->func != NULL) {
dev_dbg(xpc_chan, "ch->func() called, reason=%d, partid=%d, "
"channel=%d\n", ch->reason, ch->partid, ch->number);
ch->func(ch->reason, ch->partid, ch->number, NULL, ch->key);
dev_dbg(xpc_chan, "ch->func() returned, reason=%d, partid=%d, "
"channel=%d\n", ch->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.
*/
static enum xpc_retval
xpc_allocate_msg_wait(struct xpc_channel *ch)
{
enum xpc_retval ret;
if (ch->flags & XPC_C_DISCONNECTING) {
DBUG_ON(ch->reason == xpcInterrupted); // >>> Is this true?
return ch->reason;
}
atomic_inc(&ch->n_on_msg_allocate_wq);
ret = interruptible_sleep_on_timeout(&ch->msg_allocate_wq, 1);
atomic_dec(&ch->n_on_msg_allocate_wq);
if (ch->flags & XPC_C_DISCONNECTING) {
ret = ch->reason;
DBUG_ON(ch->reason == xpcInterrupted); // >>> Is this true?
} else if (ret == 0) {
ret = xpcTimeout;
} else {
ret = xpcInterrupted;
}
return ret;
}
/*
* Allocate an entry for a message from the message queue associated with the
* specified channel.
*/
static enum xpc_retval
xpc_allocate_msg(struct xpc_channel *ch, u32 flags,
struct xpc_msg **address_of_msg)
{
struct xpc_msg *msg;
enum xpc_retval ret;
s64 put;
/* this reference will be dropped in xpc_send_msg() */
xpc_msgqueue_ref(ch);
if (ch->flags & XPC_C_DISCONNECTING) {
xpc_msgqueue_deref(ch);
return ch->reason;
}
if (!(ch->flags & XPC_C_CONNECTED)) {
xpc_msgqueue_deref(ch);
return xpcNotConnected;
}
/*
* Get the next available message entry from the local message queue.
* If none are available, we'll make sure that we grab the latest
* GP values.
*/
ret = xpcTimeout;
while (1) {
put = (volatile s64) ch->w_local_GP.put;
if (put - (volatile s64) ch->w_remote_GP.get <
ch->local_nentries) {
/* There are available message entries. We need to try
* to secure one for ourselves. We'll do this by trying
* to increment w_local_GP.put as long as someone else
* doesn't beat us to it. If they do, we'll have to
* try again.
*/
if (cmpxchg(&ch->w_local_GP.put, put, put + 1) ==
put) {
/* we got the entry referenced by put */
break;
}
continue; /* try again */
}
/*
* There aren't any available msg entries at this time.
*
* In waiting for a message entry to become available,
* we set a timeout in case the other side is not
* sending completion IPIs. This lets us fake an IPI
* that will cause the IPI handler to fetch the latest
* GP values as if an IPI was sent by the other side.
*/
if (ret == xpcTimeout) {
xpc_IPI_send_local_msgrequest(ch);
}
if (flags & XPC_NOWAIT) {
xpc_msgqueue_deref(ch);
return xpcNoWait;
}
ret = xpc_allocate_msg_wait(ch);
if (ret != xpcInterrupted && ret != xpcTimeout) {
xpc_msgqueue_deref(ch);
return ret;
}
}
/* get the message's address and initialize it */
msg = (struct xpc_msg *) ((u64) ch->local_msgqueue +
(put % ch->local_nentries) * ch->msg_size);
DBUG_ON(msg->flags != 0);
msg->number = put;
dev_dbg(xpc_chan, "w_local_GP.put changed to %ld; msg=0x%p, "
"msg_number=%ld, partid=%d, channel=%d\n", put + 1,
(void *) msg, msg->number, ch->partid, ch->number);
*address_of_msg = msg;
return xpcSuccess;
}
/*
* Allocate an entry for a message from the message queue associated with the
* specified channel. NOTE that this routine can sleep waiting for a message
* entry to become available. To not sleep, pass in the XPC_NOWAIT flag.
*
* Arguments:
*
* partid - ID of partition to which the channel is connected.
* ch_number - channel #.
* flags - see xpc.h for valid flags.
* payload - address of the allocated payload area pointer (filled in on
* return) in which the user-defined message is constructed.
*/
enum xpc_retval
xpc_initiate_allocate(partid_t partid, int ch_number, u32 flags, void **payload)
{
struct xpc_partition *part = &xpc_partitions[partid];
enum xpc_retval ret = xpcUnknownReason;
struct xpc_msg *msg;
DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
*payload = NULL;
if (xpc_part_ref(part)) {
ret = xpc_allocate_msg(&part->channels[ch_number], flags, &msg);
xpc_part_deref(part);
if (msg != NULL) {
*payload = &msg->payload;
}
}
return ret;
}
/*
* Now we actually send the messages that are ready to be sent by advancing
* the local message queue's Put value and then send an IPI to the recipient
* partition.
*/
static void
xpc_send_msgs(struct xpc_channel *ch, s64 initial_put)
{
struct xpc_msg *msg;
s64 put = initial_put + 1;
int send_IPI = 0;
while (1) {
while (1) {
if (put == (volatile s64) ch->w_local_GP.put) {
break;
}
msg = (struct xpc_msg *) ((u64) ch->local_msgqueue +
(put % ch->local_nentries) * ch->msg_size);
if (!(msg->flags & XPC_M_READY)) {
break;
}
put++;
}
if (put == initial_put) {
/* nothing's changed */
break;
}
if (cmpxchg_rel(&ch->local_GP->put, initial_put, put) !=
initial_put) {
/* someone else beat us to it */
DBUG_ON((volatile s64) ch->local_GP->put < initial_put);
break;
}
/* we just set the new value of local_GP->put */
dev_dbg(xpc_chan, "local_GP->put changed to %ld, partid=%d, "
"channel=%d\n", put, ch->partid, ch->number);
send_IPI = 1;
/*
* We need to ensure that the message referenced by
* local_GP->put is not XPC_M_READY or that local_GP->put
* equals w_local_GP.put, so we'll go have a look.
*/
initial_put = put;
}
if (send_IPI) {
xpc_IPI_send_msgrequest(ch);
}
}
/*
* Common code that does the actual sending of the message by advancing the
* local message queue's Put value and sends an IPI to the partition the
* message is being sent to.
*/
static enum xpc_retval
xpc_send_msg(struct xpc_channel *ch, struct xpc_msg *msg, u8 notify_type,
xpc_notify_func func, void *key)
{
enum xpc_retval ret = xpcSuccess;
struct xpc_notify *notify = NULL; // >>> to keep the compiler happy!!
s64 put, msg_number = msg->number;
DBUG_ON(notify_type == XPC_N_CALL && func == NULL);
DBUG_ON((((u64) msg - (u64) ch->local_msgqueue) / ch->msg_size) !=
msg_number % ch->local_nentries);
DBUG_ON(msg->flags & XPC_M_READY);
if (ch->flags & XPC_C_DISCONNECTING) {
/* drop the reference grabbed in xpc_allocate_msg() */
xpc_msgqueue_deref(ch);
return ch->reason;
}
if (notify_type != 0) {
/*
* Tell the remote side to send an ACK interrupt when the
* message has been delivered.
*/
msg->flags |= XPC_M_INTERRUPT;
atomic_inc(&ch->n_to_notify);
notify = &ch->notify_queue[msg_number % ch->local_nentries];
notify->func = func;
notify->key = key;
(volatile u8) notify->type = notify_type;
// >>> is a mb() needed here?
if (ch->flags & XPC_C_DISCONNECTING) {
/*
* An error occurred between our last error check and
* this one. We will try to clear the type field from
* the notify entry. If we succeed then
* xpc_disconnect_channel() didn't already process
* the notify entry.
*/
if (cmpxchg(&notify->type, notify_type, 0) ==
notify_type) {
atomic_dec(&ch->n_to_notify);
ret = ch->reason;
}
/* drop the reference grabbed in xpc_allocate_msg() */
xpc_msgqueue_deref(ch);
return ret;
}
}
msg->flags |= XPC_M_READY;
/*
* The preceding store of msg->flags must occur before the following
* load of ch->local_GP->put.
*/
mb();
/* see if the message is next in line to be sent, if so send it */
put = ch->local_GP->put;
if (put == msg_number) {
xpc_send_msgs(ch, put);
}
/* drop the reference grabbed in xpc_allocate_msg() */
xpc_msgqueue_deref(ch);
return ret;
}
/*
* Send a message previously allocated using xpc_initiate_allocate() on the
* specified channel connected to the specified partition.
*
* This routine will not wait for the message to be received, nor will
* notification be given when it does happen. Once this routine has returned
* the message entry allocated via xpc_initiate_allocate() is no longer
* accessable to the caller.
*
* This routine, 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_allocate_msg().
*
* Arguments:
*
* partid - ID of partition to which the channel is connected.
* ch_number - channel # to send message on.
* payload - pointer to the payload area allocated via
* xpc_initiate_allocate().
*/
enum xpc_retval
xpc_initiate_send(partid_t partid, int ch_number, void *payload)
{
struct xpc_partition *part = &xpc_partitions[partid];
struct xpc_msg *msg = XPC_MSG_ADDRESS(payload);
enum xpc_retval ret;
dev_dbg(xpc_chan, "msg=0x%p, partid=%d, channel=%d\n", (void *) msg,
partid, ch_number);
DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
DBUG_ON(msg == NULL);
ret = xpc_send_msg(&part->channels[ch_number], msg, 0, NULL, NULL);
return ret;
}
/*
* Send a message previously allocated using xpc_initiate_allocate on the
* specified channel connected to the specified partition.
*
* This routine will not wait for the message to be sent. Once this routine
* has returned the message entry allocated via xpc_initiate_allocate() is no
* longer accessable to the caller.
*
* 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.
*
* This routine, 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_allocate_msg().
*
* Arguments:
*
* partid - ID of partition to which the channel is connected.
* ch_number - channel # to send message on.
* payload - pointer to the payload area allocated via
* xpc_initiate_allocate().
* 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 xpc_retval
xpc_initiate_send_notify(partid_t partid, int ch_number, void *payload,
xpc_notify_func func, void *key)
{
struct xpc_partition *part = &xpc_partitions[partid];
struct xpc_msg *msg = XPC_MSG_ADDRESS(payload);
enum xpc_retval ret;
dev_dbg(xpc_chan, "msg=0x%p, partid=%d, channel=%d\n", (void *) msg,
partid, ch_number);
DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
DBUG_ON(msg == NULL);
DBUG_ON(func == NULL);
ret = xpc_send_msg(&part->channels[ch_number], msg, XPC_N_CALL,
func, key);
return ret;
}
static struct xpc_msg *
xpc_pull_remote_msg(struct xpc_channel *ch, s64 get)
{
struct xpc_partition *part = &xpc_partitions[ch->partid];
struct xpc_msg *remote_msg, *msg;
u32 msg_index, nmsgs;
u64 msg_offset;
enum xpc_retval ret;
if (down_interruptible(&ch->msg_to_pull_sema) != 0) {
/* we were interrupted by a signal */
return NULL;
}
while (get >= ch->next_msg_to_pull) {
/* pull as many messages as are ready and able to be pulled */
msg_index = ch->next_msg_to_pull % ch->remote_nentries;
DBUG_ON(ch->next_msg_to_pull >=
(volatile s64) ch->w_remote_GP.put);
nmsgs = (volatile s64) ch->w_remote_GP.put -
ch->next_msg_to_pull;
if (msg_index + nmsgs > ch->remote_nentries) {
/* ignore the ones that wrap the msg queue for now */
nmsgs = ch->remote_nentries - msg_index;
}
msg_offset = msg_index * ch->msg_size;
msg = (struct xpc_msg *) ((u64) ch->remote_msgqueue +
msg_offset);
remote_msg = (struct xpc_msg *) (ch->remote_msgqueue_pa +
msg_offset);
if ((ret = xpc_pull_remote_cachelines(part, msg, remote_msg,
nmsgs * ch->msg_size)) != xpcSuccess) {
dev_dbg(xpc_chan, "failed to pull %d msgs starting with"
" msg %ld from partition %d, channel=%d, "
"ret=%d\n", nmsgs, ch->next_msg_to_pull,
ch->partid, ch->number, ret);
XPC_DEACTIVATE_PARTITION(part, ret);
up(&ch->msg_to_pull_sema);
return NULL;
}
mb(); /* >>> this may not be needed, we're not sure */
ch->next_msg_to_pull += nmsgs;
}
up(&ch->msg_to_pull_sema);
/* return the message we were looking for */
msg_offset = (get % ch->remote_nentries) * ch->msg_size;
msg = (struct xpc_msg *) ((u64) ch->remote_msgqueue + msg_offset);
return msg;
}
/*
* Get a message to be delivered.
*/
static struct xpc_msg *
xpc_get_deliverable_msg(struct xpc_channel *ch)
{
struct xpc_msg *msg = NULL;
s64 get;
do {
if ((volatile u32) ch->flags & XPC_C_DISCONNECTING) {
break;
}
get = (volatile s64) ch->w_local_GP.get;
if (get == (volatile s64) ch->w_remote_GP.put) {
break;
}
/* There are messages waiting to be pulled and delivered.
* We need to try to secure one for ourselves. We'll do this
* by trying to increment w_local_GP.get and hope that no one
* else beats us to it. If they do, we'll we'll simply have
* to try again for the next one.
*/
if (cmpxchg(&ch->w_local_GP.get, get, get + 1) == get) {
/* we got the entry referenced by get */
dev_dbg(xpc_chan, "w_local_GP.get changed to %ld, "
"partid=%d, channel=%d\n", get + 1,
ch->partid, ch->number);
/* pull the message from the remote partition */
msg = xpc_pull_remote_msg(ch, get);
DBUG_ON(msg != NULL && msg->number != get);
DBUG_ON(msg != NULL && (msg->flags & XPC_M_DONE));
DBUG_ON(msg != NULL && !(msg->flags & XPC_M_READY));
break;
}
} while (1);
return msg;
}
/*
* Deliver a message to its intended recipient.
*/
void
xpc_deliver_msg(struct xpc_channel *ch)
{
struct xpc_msg *msg;
if ((msg = xpc_get_deliverable_msg(ch)) != 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, msg=0x%p, "
"msg_number=%ld, partid=%d, channel=%d\n",
(void *) msg, msg->number, ch->partid,
ch->number);
/* deliver the message to its intended recipient */
ch->func(xpcMsgReceived, ch->partid, ch->number,
&msg->payload, ch->key);
dev_dbg(xpc_chan, "ch->func() returned, msg=0x%p, "
"msg_number=%ld, partid=%d, channel=%d\n",
(void *) msg, msg->number, ch->partid,
ch->number);
}
atomic_dec(&ch->kthreads_active);
}
}
/*
* Now we actually acknowledge the messages that have been delivered and ack'd
* by advancing the cached remote message queue's Get value and if requested
* send an IPI to the message sender's partition.
*/
static void
xpc_acknowledge_msgs(struct xpc_channel *ch, s64 initial_get, u8 msg_flags)
{
struct xpc_msg *msg;
s64 get = initial_get + 1;
int send_IPI = 0;
while (1) {
while (1) {
if (get == (volatile s64) ch->w_local_GP.get) {
break;
}
msg = (struct xpc_msg *) ((u64) ch->remote_msgqueue +
(get % ch->remote_nentries) * ch->msg_size);
if (!(msg->flags & XPC_M_DONE)) {
break;
}
msg_flags |= msg->flags;
get++;
}
if (get == initial_get) {
/* nothing's changed */
break;
}
if (cmpxchg_rel(&ch->local_GP->get, initial_get, get) !=
initial_get) {
/* someone else beat us to it */
DBUG_ON((volatile s64) ch->local_GP->get <=
initial_get);
break;
}
/* we just set the new value of local_GP->get */
dev_dbg(xpc_chan, "local_GP->get changed to %ld, partid=%d, "
"channel=%d\n", get, ch->partid, ch->number);
send_IPI = (msg_flags & XPC_M_INTERRUPT);
/*
* We need to ensure that the message referenced by
* local_GP->get is not XPC_M_DONE or that local_GP->get
* equals w_local_GP.get, so we'll go have a look.
*/
initial_get = get;
}
if (send_IPI) {
xpc_IPI_send_msgrequest(ch);
}
}
/*
* Acknowledge receipt of a delivered message.
*
* If a message has XPC_M_INTERRUPT set, send an interrupt to the partition
* that sent the message.
*
* 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_msg().
*
* 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_allocate().
*/
void
xpc_initiate_received(partid_t partid, int ch_number, void *payload)
{
struct xpc_partition *part = &xpc_partitions[partid];
struct xpc_channel *ch;
struct xpc_msg *msg = XPC_MSG_ADDRESS(payload);
s64 get, msg_number = msg->number;
DBUG_ON(partid <= 0 || partid >= XP_MAX_PARTITIONS);
DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
ch = &part->channels[ch_number];
dev_dbg(xpc_chan, "msg=0x%p, msg_number=%ld, partid=%d, channel=%d\n",
(void *) msg, msg_number, ch->partid, ch->number);
DBUG_ON((((u64) msg - (u64) ch->remote_msgqueue) / ch->msg_size) !=
msg_number % ch->remote_nentries);
DBUG_ON(msg->flags & XPC_M_DONE);
msg->flags |= XPC_M_DONE;
/*
* The preceding store of msg->flags must occur before the following
* load of ch->local_GP->get.
*/
mb();
/*
* See if this message is next in line to be acknowledged as having
* been delivered.
*/
get = ch->local_GP->get;
if (get == msg_number) {
xpc_acknowledge_msgs(ch, get, msg->flags);
}
/* the call to xpc_msgqueue_ref() was done by xpc_deliver_msg() */
xpc_msgqueue_deref(ch);
}
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