/* $NetBSD: rf_engine.c,v 1.53 2019/10/10 03:43:59 christos Exp $ */
/*
* Copyright (c) 1995 Carnegie-Mellon University.
* All rights reserved.
*
* Author: William V. Courtright II, Mark Holland, Rachad Youssef
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/****************************************************************************
* *
* engine.c -- code for DAG execution engine *
* *
* Modified to work as follows (holland): *
* A user-thread calls into DispatchDAG, which fires off the nodes that *
* are direct successors to the header node. DispatchDAG then returns, *
* and the rest of the I/O continues asynchronously. As each node *
* completes, the node execution function calls FinishNode(). FinishNode *
* scans the list of successors to the node and increments the antecedent *
* counts. Each node that becomes enabled is placed on a central node *
* queue. A dedicated dag-execution thread grabs nodes off of this *
* queue and fires them. *
* *
* NULL nodes are never fired. *
* *
* Terminator nodes are never fired, but rather cause the callback *
* associated with the DAG to be invoked. *
* *
* If a node fails, the dag either rolls forward to the completion or *
* rolls back, undoing previously-completed nodes and fails atomically. *
* The direction of recovery is determined by the location of the failed *
* node in the graph. If the failure occurred before the commit node in *
* the graph, backward recovery is used. Otherwise, forward recovery is *
* used. *
* *
****************************************************************************/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: rf_engine.c,v 1.53 2019/10/10 03:43:59 christos Exp $");
#include <sys/errno.h>
#include "rf_threadstuff.h"
#include "rf_dag.h"
#include "rf_engine.h"
#include "rf_etimer.h"
#include "rf_general.h"
#include "rf_dagutils.h"
#include "rf_shutdown.h"
#include "rf_raid.h"
#include "rf_kintf.h"
#include "rf_paritymap.h"
static void rf_ShutdownEngine(void *);
static void DAGExecutionThread(RF_ThreadArg_t arg);
static void rf_RaidIOThread(RF_ThreadArg_t arg);
/* synchronization primitives for this file. DO_WAIT should be enclosed in a while loop. */
#define DO_LOCK(_r_) \
rf_lock_mutex2((_r_)->node_queue_mutex)
#define DO_UNLOCK(_r_) \
rf_unlock_mutex2((_r_)->node_queue_mutex)
#define DO_WAIT(_r_) \
rf_wait_cond2((_r_)->node_queue_cv, (_r_)->node_queue_mutex)
#define DO_SIGNAL(_r_) \
rf_broadcast_cond2((_r_)->node_queue_cv) /* XXX rf_signal_cond2? */
static void
rf_ShutdownEngine(void *arg)
{
RF_Raid_t *raidPtr;
raidPtr = (RF_Raid_t *) arg;
/* Tell the rf_RaidIOThread to shutdown */
rf_lock_mutex2(raidPtr->iodone_lock);
raidPtr->shutdown_raidio = 1;
rf_signal_cond2(raidPtr->iodone_cv);
/* ...and wait for it to tell us it has finished */
while (raidPtr->shutdown_raidio)
rf_wait_cond2(raidPtr->iodone_cv, raidPtr->iodone_lock);
rf_unlock_mutex2(raidPtr->iodone_lock);
/* Now shut down the DAG execution engine. */
DO_LOCK(raidPtr);
raidPtr->shutdown_engine = 1;
DO_SIGNAL(raidPtr);
/* ...and wait for it to tell us it has finished */
while (raidPtr->shutdown_engine)
DO_WAIT(raidPtr);
DO_UNLOCK(raidPtr);
rf_destroy_mutex2(raidPtr->node_queue_mutex);
rf_destroy_cond2(raidPtr->node_queue_cv);
rf_destroy_mutex2(raidPtr->iodone_lock);
rf_destroy_cond2(raidPtr->iodone_cv);
}
int
rf_ConfigureEngine(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr,
RF_Config_t *cfgPtr)
{
/*
* Initialise iodone for the IO thread.
*/
TAILQ_INIT(&(raidPtr->iodone));
rf_init_mutex2(raidPtr->iodone_lock, IPL_VM);
rf_init_cond2(raidPtr->iodone_cv, "raidiow");
rf_init_mutex2(raidPtr->node_queue_mutex, IPL_VM);
rf_init_cond2(raidPtr->node_queue_cv, "rfnodeq");
raidPtr->node_queue = NULL;
raidPtr->dags_in_flight = 0;
/* we create the execution thread only once per system boot. no need
* to check return code b/c the kernel panics if it can't create the
* thread. */
#if RF_DEBUG_ENGINE
if (rf_engineDebug) {
printf("raid%d: Creating engine thread\n", raidPtr->raidid);
}
#endif
if (RF_CREATE_ENGINE_THREAD(raidPtr->engine_thread,
DAGExecutionThread, raidPtr,
"raid%d", raidPtr->raidid)) {
printf("raid%d: Unable to create engine thread\n",
raidPtr->raidid);
return (ENOMEM);
}
if (RF_CREATE_ENGINE_THREAD(raidPtr->engine_helper_thread,
rf_RaidIOThread, raidPtr,
"raidio%d", raidPtr->raidid)) {
printf("raid%d: Unable to create raidio thread\n",
raidPtr->raidid);
return (ENOMEM);
}
#if RF_DEBUG_ENGINE
if (rf_engineDebug) {
printf("raid%d: Created engine thread\n", raidPtr->raidid);
}
#endif
/* engine thread is now running and waiting for work */
#if RF_DEBUG_ENGINE
if (rf_engineDebug) {
printf("raid%d: Engine thread running and waiting for events\n", raidPtr->raidid);
}
#endif
rf_ShutdownCreate(listp, rf_ShutdownEngine, raidPtr);
return (0);
}
#if 0
static int
BranchDone(RF_DagNode_t *node)
{
int i;
/* return true if forward execution is completed for a node and its
* succedents */
switch (node->status) {
case rf_wait:
/* should never be called in this state */
RF_PANIC();
break;
case rf_fired:
/* node is currently executing, so we're not done */
return (RF_FALSE);
case rf_good:
/* for each succedent recursively check branch */
for (i = 0; i < node->numSuccedents; i++)
if (!BranchDone(node->succedents[i]))
return RF_FALSE;
return RF_TRUE; /* node and all succedent branches aren't in
* fired state */
case rf_bad:
/* succedents can't fire */
return (RF_TRUE);
case rf_recover:
/* should never be called in this state */
RF_PANIC();
break;
case rf_undone:
case rf_panic:
/* XXX need to fix this case */
/* for now, assume that we're done */
return (RF_TRUE);
default:
/* illegal node status */
RF_PANIC();
break;
}
}
#endif
static int
NodeReady(RF_DagNode_t *node)
{
int ready;
ready = RF_FALSE;
switch (node->dagHdr->status) {
case rf_enable:
case rf_rollForward:
if ((node->status == rf_wait) &&
(node->numAntecedents == node->numAntDone))
ready = RF_TRUE;
break;
case rf_rollBackward:
RF_ASSERT(node->numSuccDone <= node->numSuccedents);
RF_ASSERT(node->numSuccFired <= node->numSuccedents);
RF_ASSERT(node->numSuccFired <= node->numSuccDone);
if ((node->status == rf_good) &&
(node->numSuccDone == node->numSuccedents))
ready = RF_TRUE;
break;
default:
printf("Execution engine found illegal DAG status in NodeReady\n");
RF_PANIC();
break;
}
return (ready);
}
/* user context and dag-exec-thread context: Fire a node. The node's
* status field determines which function, do or undo, to be fired.
* This routine assumes that the node's status field has alread been
* set to "fired" or "recover" to indicate the direction of execution.
*/
static void
FireNode(RF_DagNode_t *node)
{
switch (node->status) {
case rf_fired:
/* fire the do function of a node */
#if RF_DEBUG_ENGINE
if (rf_engineDebug) {
printf("raid%d: Firing node 0x%lx (%s)\n",
node->dagHdr->raidPtr->raidid,
(unsigned long) node, node->name);
}
#endif
if (node->flags & RF_DAGNODE_FLAG_YIELD) {
#if defined(__NetBSD__) && defined(_KERNEL)
/* thread_block(); */
/* printf("Need to block the thread here...\n"); */
/* XXX thread_block is actually mentioned in
* /usr/include/vm/vm_extern.h */
#else
thread_block();
#endif
}
(*(node->doFunc)) (node);
break;
case rf_recover:
/* fire the undo function of a node */
#if RF_DEBUG_ENGINE
if (rf_engineDebug) {
printf("raid%d: Firing (undo) node 0x%lx (%s)\n",
node->dagHdr->raidPtr->raidid,
(unsigned long) node, node->name);
}
#endif
if (node->flags & RF_DAGNODE_FLAG_YIELD)
#if defined(__NetBSD__) && defined(_KERNEL)
/* thread_block(); */
/* printf("Need to block the thread here...\n"); */
/* XXX thread_block is actually mentioned in
* /usr/include/vm/vm_extern.h */
#else
thread_block();
#endif
(*(node->undoFunc)) (node);
break;
default:
RF_PANIC();
break;
}
}
/* user context:
* Attempt to fire each node in a linear array.
* The entire list is fired atomically.
*/
static void
FireNodeArray(int numNodes, RF_DagNode_t **nodeList)
{
RF_DagStatus_t dstat;
RF_DagNode_t *node;
int i, j;
/* first, mark all nodes which are ready to be fired */
for (i = 0; i < numNodes; i++) {
node = nodeList[i];
dstat = node->dagHdr->status;
RF_ASSERT((node->status == rf_wait) ||
(node->status == rf_good));
if (NodeReady(node)) {
if ((dstat == rf_enable) ||
(dstat == rf_rollForward)) {
RF_ASSERT(node->status == rf_wait);
if (node->commitNode)
node->dagHdr->numCommits++;
node->status = rf_fired;
for (j = 0; j < node->numAntecedents; j++)
node->antecedents[j]->numSuccFired++;
} else {
RF_ASSERT(dstat == rf_rollBackward);
RF_ASSERT(node->status == rf_good);
/* only one commit node per graph */
RF_ASSERT(node->commitNode == RF_FALSE);
node->status = rf_recover;
}
}
}
/* now, fire the nodes */
for (i = 0; i < numNodes; i++) {
if ((nodeList[i]->status == rf_fired) ||
(nodeList[i]->status == rf_recover))
FireNode(nodeList[i]);
}
}
/* user context:
* Attempt to fire each node in a linked list.
* The entire list is fired atomically.
*/
static void
FireNodeList(RF_DagNode_t *nodeList)
{
RF_DagNode_t *node, *next;
RF_DagStatus_t dstat;
int j;
if (nodeList) {
/* first, mark all nodes which are ready to be fired */
for (node = nodeList; node; node = next) {
next = node->next;
dstat = node->dagHdr->status;
RF_ASSERT((node->status == rf_wait) ||
(node->status == rf_good));
if (NodeReady(node)) {
if ((dstat == rf_enable) ||
(dstat == rf_rollForward)) {
RF_ASSERT(node->status == rf_wait);
if (node->commitNode)
node->dagHdr->numCommits++;
node->status = rf_fired;
for (j = 0; j < node->numAntecedents; j++)
node->antecedents[j]->numSuccFired++;
} else {
RF_ASSERT(dstat == rf_rollBackward);
RF_ASSERT(node->status == rf_good);
/* only one commit node per graph */
RF_ASSERT(node->commitNode == RF_FALSE);
node->status = rf_recover;
}
}
}
/* now, fire the nodes */
for (node = nodeList; node; node = next) {
next = node->next;
if ((node->status == rf_fired) ||
(node->status == rf_recover))
FireNode(node);
}
}
}
/* interrupt context:
* for each succedent
* propagate required results from node to succedent
* increment succedent's numAntDone
* place newly-enable nodes on node queue for firing
*
* To save context switches, we don't place NIL nodes on the node queue,
* but rather just process them as if they had fired. Note that NIL nodes
* that are the direct successors of the header will actually get fired by
* DispatchDAG, which is fine because no context switches are involved.
*
* Important: when running at user level, this can be called by any
* disk thread, and so the increment and check of the antecedent count
* must be locked. I used the node queue mutex and locked down the
* entire function, but this is certainly overkill.
*/
static void
PropagateResults(RF_DagNode_t *node, int context)
{
RF_DagNode_t *s, *a;
RF_Raid_t *raidPtr;
int i;
RF_DagNode_t *finishlist = NULL; /* a list of NIL nodes to be
* finished */
RF_DagNode_t *skiplist = NULL; /* list of nodes with failed truedata
* antecedents */
RF_DagNode_t *firelist = NULL; /* a list of nodes to be fired */
RF_DagNode_t *q = NULL, *qh = NULL, *next;
int j, skipNode;
raidPtr = node->dagHdr->raidPtr;
DO_LOCK(raidPtr);
/* debug - validate fire counts */
for (i = 0; i < node->numAntecedents; i++) {
a = *(node->antecedents + i);
RF_ASSERT(a->numSuccFired >= a->numSuccDone);
RF_ASSERT(a->numSuccFired <= a->numSuccedents);
a->numSuccDone++;
}
switch (node->dagHdr->status) {
case rf_enable:
case rf_rollForward:
for (i = 0; i < node->numSuccedents; i++) {
s = *(node->succedents + i);
RF_ASSERT(s->status == rf_wait);
(s->numAntDone)++;
if (s->numAntDone == s->numAntecedents) {
/* look for NIL nodes */
if (s->doFunc == rf_NullNodeFunc) {
/* don't fire NIL nodes, just process
* them */
s->next = finishlist;
finishlist = s;
} else {
/* look to see if the node is to be
* skipped */
skipNode = RF_FALSE;
for (j = 0; j < s->numAntecedents; j++)
if ((s->antType[j] == rf_trueData) && (s->antecedents[j]->status == rf_bad))
skipNode = RF_TRUE;
if (skipNode) {
/* this node has one or more
* failed true data
* dependencies, so skip it */
s->next = skiplist;
skiplist = s;
} else
/* add s to list of nodes (q)
* to execute */
if (context != RF_INTR_CONTEXT) {
/* we only have to
* enqueue if we're at
* intr context */
/* put node on
a list to
be fired
after we
unlock */
s->next = firelist;
firelist = s;
} else {
/* enqueue the
node for
the dag
exec thread
to fire */
RF_ASSERT(NodeReady(s));
if (q) {
q->next = s;
q = s;
} else {
qh = q = s;
qh->next = NULL;
}
}
}
}
}
if (q) {
/* xfer our local list of nodes to the node queue */
q->next = raidPtr->node_queue;
raidPtr->node_queue = qh;
DO_SIGNAL(raidPtr);
}
DO_UNLOCK(raidPtr);
for (; skiplist; skiplist = next) {
next = skiplist->next;
skiplist->status = rf_skipped;
for (i = 0; i < skiplist->numAntecedents; i++) {
skiplist->antecedents[i]->numSuccFired++;
}
if (skiplist->commitNode) {
skiplist->dagHdr->numCommits++;
}
rf_FinishNode(skiplist, context);
}
for (; finishlist; finishlist = next) {
/* NIL nodes: no need to fire them */
next = finishlist->next;
finishlist->status = rf_good;
for (i = 0; i < finishlist->numAntecedents; i++) {
finishlist->antecedents[i]->numSuccFired++;
}
if (finishlist->commitNode)
finishlist->dagHdr->numCommits++;
/*
* Okay, here we're calling rf_FinishNode() on
* nodes that have the null function as their
* work proc. Such a node could be the
* terminal node in a DAG. If so, it will
* cause the DAG to complete, which will in
* turn free memory used by the DAG, which
* includes the node in question. Thus, we
* must avoid referencing the node at all
* after calling rf_FinishNode() on it. */
rf_FinishNode(finishlist, context); /* recursive call */
}
/* fire all nodes in firelist */
FireNodeList(firelist);
break;
case rf_rollBackward:
for (i = 0; i < node->numAntecedents; i++) {
a = *(node->antecedents + i);
RF_ASSERT(a->status == rf_good);
RF_ASSERT(a->numSuccDone <= a->numSuccedents);
RF_ASSERT(a->numSuccDone <= a->numSuccFired);
if (a->numSuccDone == a->numSuccFired) {
if (a->undoFunc == rf_NullNodeFunc) {
/* don't fire NIL nodes, just process
* them */
a->next = finishlist;
finishlist = a;
} else {
if (context != RF_INTR_CONTEXT) {
/* we only have to enqueue if
* we're at intr context */
/* put node on a list to be
fired after we unlock */
a->next = firelist;
firelist = a;
} else {
/* enqueue the node for the
dag exec thread to fire */
RF_ASSERT(NodeReady(a));
if (q) {
q->next = a;
q = a;
} else {
qh = q = a;
qh->next = NULL;
}
}
}
}
}
if (q) {
/* xfer our local list of nodes to the node queue */
q->next = raidPtr->node_queue;
raidPtr->node_queue = qh;
DO_SIGNAL(raidPtr);
}
DO_UNLOCK(raidPtr);
for (; finishlist; finishlist = next) {
/* NIL nodes: no need to fire them */
next = finishlist->next;
finishlist->status = rf_good;
/*
* Okay, here we're calling rf_FinishNode() on
* nodes that have the null function as their
* work proc. Such a node could be the first
* node in a DAG. If so, it will cause the DAG
* to complete, which will in turn free memory
* used by the DAG, which includes the node in
* question. Thus, we must avoid referencing
* the node at all after calling
* rf_FinishNode() on it. */
rf_FinishNode(finishlist, context); /* recursive call */
}
/* fire all nodes in firelist */
FireNodeList(firelist);
break;
default:
printf("Engine found illegal DAG status in PropagateResults()\n");
RF_PANIC();
break;
}
}
/*
* Process a fired node which has completed
*/
static void
ProcessNode(RF_DagNode_t *node, int context)
{
#if RF_DEBUG_ENGINE
RF_Raid_t *raidPtr;
raidPtr = node->dagHdr->raidPtr;
#endif
switch (node->status) {
case rf_good:
/* normal case, don't need to do anything */
break;
case rf_bad:
if ((node->dagHdr->numCommits > 0) ||
(node->dagHdr->numCommitNodes == 0)) {
/* crossed commit barrier */
node->dagHdr->status = rf_rollForward;
#if RF_DEBUG_ENGINE
if (rf_engineDebug) {
printf("raid%d: node (%s) returned fail, rolling forward\n", raidPtr->raidid, node->name);
}
#endif
} else {
/* never reached commit barrier */
node->dagHdr->status = rf_rollBackward;
#if RF_DEBUG_ENGINE
if (rf_engineDebug) {
printf("raid%d: node (%s) returned fail, rolling backward\n", raidPtr->raidid, node->name);
}
#endif
}
break;
case rf_undone:
/* normal rollBackward case, don't need to do anything */
break;
case rf_panic:
/* an undo node failed!!! */
printf("UNDO of a node failed!!!\n");
break;
default:
printf("node finished execution with an illegal status!!!\n");
RF_PANIC();
break;
}
/* enqueue node's succedents (antecedents if rollBackward) for
* execution */
PropagateResults(node, context);
}
/* user context or dag-exec-thread context:
* This is the first step in post-processing a newly-completed node.
* This routine is called by each node execution function to mark the node
* as complete and fire off any successors that have been enabled.
*/
void
rf_FinishNode(RF_DagNode_t *node, int context)
{
node->dagHdr->numNodesCompleted++;
ProcessNode(node, context);
}
/* user context: submit dag for execution, return non-zero if we have
* to wait for completion. if and only if we return non-zero, we'll
* cause cbFunc to get invoked with cbArg when the DAG has completed.
*
* for now we always return 1. If the DAG does not cause any I/O,
* then the callback may get invoked before DispatchDAG returns.
* There's code in state 5 of ContinueRaidAccess to handle this.
*
* All we do here is fire the direct successors of the header node.
* The DAG execution thread does the rest of the dag processing. */
int
rf_DispatchDAG(RF_DagHeader_t *dag, void (*cbFunc) (void *),
void *cbArg)
{
RF_Raid_t *raidPtr;
raidPtr = dag->raidPtr;
#if RF_ACC_TRACE > 0
if (dag->tracerec) {
RF_ETIMER_START(dag->tracerec->timer);
}
#endif
#if DEBUG
#if RF_DEBUG_VALIDATE_DAG
if (rf_engineDebug || rf_validateDAGDebug) {
if (rf_ValidateDAG(dag))
RF_PANIC();
}
#endif
#endif
#if RF_DEBUG_ENGINE
if (rf_engineDebug) {
printf("raid%d: Entering DispatchDAG\n", raidPtr->raidid);
}
#endif
raidPtr->dags_in_flight++; /* debug only: blow off proper
* locking */
dag->cbFunc = cbFunc;
dag->cbArg = cbArg;
dag->numNodesCompleted = 0;
dag->status = rf_enable;
FireNodeArray(dag->numSuccedents, dag->succedents);
return (1);
}
/* dedicated kernel thread: the thread that handles all DAG node
* firing. To minimize locking and unlocking, we grab a copy of the
* entire node queue and then set the node queue to NULL before doing
* any firing of nodes. This way we only have to release the lock
* once. Of course, it's probably rare that there's more than one
* node in the queue at any one time, but it sometimes happens.
*/
static void
DAGExecutionThread(RF_ThreadArg_t arg)
{
RF_DagNode_t *nd, *local_nq, *term_nq, *fire_nq;
RF_Raid_t *raidPtr;
raidPtr = (RF_Raid_t *) arg;
#if RF_DEBUG_ENGINE
if (rf_engineDebug) {
printf("raid%d: Engine thread is running\n", raidPtr->raidid);
}
#endif
DO_LOCK(raidPtr);
while (!raidPtr->shutdown_engine) {
while (raidPtr->node_queue != NULL) {
local_nq = raidPtr->node_queue;
fire_nq = NULL;
term_nq = NULL;
raidPtr->node_queue = NULL;
DO_UNLOCK(raidPtr);
/* first, strip out the terminal nodes */
while (local_nq) {
nd = local_nq;
local_nq = local_nq->next;
switch (nd->dagHdr->status) {
case rf_enable:
case rf_rollForward:
if (nd->numSuccedents == 0) {
/* end of the dag, add to
* callback list */
nd->next = term_nq;
term_nq = nd;
} else {
/* not the end, add to the
* fire queue */
nd->next = fire_nq;
fire_nq = nd;
}
break;
case rf_rollBackward:
if (nd->numAntecedents == 0) {
/* end of the dag, add to the
* callback list */
nd->next = term_nq;
term_nq = nd;
} else {
/* not the end, add to the
* fire queue */
nd->next = fire_nq;
fire_nq = nd;
}
break;
default:
RF_PANIC();
break;
}
}
/* execute callback of dags which have reached the
* terminal node */
while (term_nq) {
nd = term_nq;
term_nq = term_nq->next;
nd->next = NULL;
(nd->dagHdr->cbFunc) (nd->dagHdr->cbArg);
raidPtr->dags_in_flight--; /* debug only */
}
/* fire remaining nodes */
FireNodeList(fire_nq);
DO_LOCK(raidPtr);
}
while (!raidPtr->shutdown_engine &&
raidPtr->node_queue == NULL) {
DO_WAIT(raidPtr);
}
}
/* Let rf_ShutdownEngine know that we're done... */
raidPtr->shutdown_engine = 0;
DO_SIGNAL(raidPtr);
DO_UNLOCK(raidPtr);
kthread_exit(0);
}
/*
* rf_RaidIOThread() -- When I/O to a component begins, raidstrategy()
* puts the I/O on a buffer queue, and then signals raidPtr->iodone. If
* necessary, this function calls raidstart() to initiate the I/O.
* When I/O to a component completes, KernelWakeupFunc() puts the
* completed request onto raidPtr->iodone TAILQ. This function looks
* after requests on that queue by calling rf_DiskIOComplete() for the
* request, and by calling any required CompleteFunc for the request.
*/
static void
rf_RaidIOThread(RF_ThreadArg_t arg)
{
RF_Raid_t *raidPtr;
RF_DiskQueueData_t *req;
raidPtr = (RF_Raid_t *) arg;
rf_lock_mutex2(raidPtr->iodone_lock);
while (!raidPtr->shutdown_raidio) {
/* if there is nothing to do, then snooze. */
if (TAILQ_EMPTY(&(raidPtr->iodone)) &&
rf_buf_queue_check(raidPtr)) {
rf_wait_cond2(raidPtr->iodone_cv, raidPtr->iodone_lock);
}
/* Check for deferred parity-map-related work. */
if (raidPtr->parity_map != NULL) {
rf_unlock_mutex2(raidPtr->iodone_lock);
rf_paritymap_checkwork(raidPtr->parity_map);
rf_lock_mutex2(raidPtr->iodone_lock);
}
/* See what I/Os, if any, have arrived */
while ((req = TAILQ_FIRST(&(raidPtr->iodone))) != NULL) {
TAILQ_REMOVE(&(raidPtr->iodone), req, iodone_entries);
rf_unlock_mutex2(raidPtr->iodone_lock);
rf_DiskIOComplete(req->queue, req, req->error);
(req->CompleteFunc) (req->argument, req->error);
rf_lock_mutex2(raidPtr->iodone_lock);
}
/* process any pending outgoing IO */
rf_unlock_mutex2(raidPtr->iodone_lock);
raidstart(raidPtr);
rf_lock_mutex2(raidPtr->iodone_lock);
}
/* Let rf_ShutdownEngine know that we're done... */
raidPtr->shutdown_raidio = 0;
rf_signal_cond2(raidPtr->iodone_cv);
rf_unlock_mutex2(raidPtr->iodone_lock);
kthread_exit(0);
}