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Fix a problem with the way we schedule work on the NDIS worker threads.

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The Am1771 driver will sometimes do the following:

- Some thread-> NdisScheduleWorkItem(some work)
- Worker thread -> do some work, KeWaitForSingleObject(some event)
- Some other thread -> NdisScheduleWorkItem(some other work)

When the second call to NdisScheduleWorkItem() occurs, the NDIS worker
thread (in our case ndis taskqueue) is suspended in KeWaitForSingleObject()
and waiting for an event to be signaled. This is different from when
the worker thread is idle and waiting on NdisScheduleWorkItem() to
send it more jobs. However, the ndis_sched() function in kern_ndis.c
always calls kthread_resume() when queueing a new job. Normally this
would be ok, but here this causes KeWaitForSingleObject() to return
prematurely, which is not what we want.

To fix this, the NDIS threads created by kern_ndis.c maintain a state
variable to indicate whether they are running (scanning the job list
and executing jobs) or sleeping (blocked on kthread_suspend() in
ndis_runq()), and ndis_sched() will only call kthread_resume() if
the thread is in the sleeping state.

Note that we can't just check to see if the thread is on the run queue:
in both cases, the thread is sleeping, but it's sleeping for different
reasons.

This stops the Am1771 driver from emitting various "NDIS ERROR" messages
and fixes some cases where it crashes.
This commit is contained in:
Bill Paul 2004-02-14 20:57:32 +00:00
parent 07c6a85154
commit 134164f8d3
2 changed files with 22 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
sys/compat/ndis/kern_ndis.c
View File

@ -99,6 +99,7 @@ struct ndis_req {
struct ndisproc {
struct ndisqhead *np_q;
struct proc *np_p;
int np_state;
};
static int ndis_create_kthreads(void);
@ -214,6 +215,7 @@ ndis_runq(arg)
/* Look for any jobs on the work queue. */
mtx_pool_lock(ndis_mtxpool, ndis_thr_mtx);
p->np_state = NDIS_PSTATE_RUNNING;
while(STAILQ_FIRST(p->np_q) != NULL) {
r = STAILQ_FIRST(p->np_q);
STAILQ_REMOVE_HEAD(p->np_q, link);
@ -232,6 +234,7 @@ ndis_runq(arg)
if (r->nr_exit == TRUE)
die = r;
}
p->np_state = NDIS_PSTATE_SLEEPING;
mtx_pool_unlock(ndis_mtxpool, ndis_thr_mtx);
/* Bail if we were told to shut down. */
@ -267,12 +270,14 @@ ndis_create_kthreads()
if (error == 0) {
ndis_tproc.np_q = &ndis_ttodo;
ndis_tproc.np_state = NDIS_PSTATE_SLEEPING;
error = kthread_create(ndis_runq, &ndis_tproc,
&ndis_tproc.np_p, RFHIGHPID, 0, "ndis taskqueue");
}
if (error == 0) {
ndis_iproc.np_q = &ndis_itodo;
ndis_iproc.np_state = NDIS_PSTATE_SLEEPING;
error = kthread_create(ndis_runq, &ndis_iproc,
&ndis_iproc.np_p, RFHIGHPID, 0, "ndis swi");
}
@ -408,6 +413,7 @@ ndis_sched(func, arg, t)
struct ndis_req *r;
struct ndisqhead *q;
struct proc *p;
int s;
if (t == NDIS_TASKQUEUE) {
q = &ndis_ttodo;
@ -438,10 +444,21 @@ ndis_sched(func, arg, t)
r->nr_arg = arg;
r->nr_exit = FALSE;
STAILQ_INSERT_TAIL(q, r, link);
if (t == NDIS_TASKQUEUE)
s = ndis_tproc.np_state;
else
s = ndis_iproc.np_state;
mtx_pool_unlock(ndis_mtxpool, ndis_thr_mtx);
/* Post the job. */
kthread_resume(p);
/*
* Post the job, but only if the thread is actually blocked
* on its own suspend call. If a driver queues up a job with
* NdisScheduleWorkItem() which happens to do a KeWaitForObject(),
* it may suspend there, and in that case we don't want to wake
* it up until KeWaitForObject() gets woken up on its own.
*/
if (s == NDIS_PSTATE_SLEEPING)
kthread_resume(p);
return(0);
}

3
sys/compat/ndis/ndis_var.h
View File

@ -1475,6 +1475,9 @@ extern image_patch_table ndis_functbl[];
#define NDIS_TASKQUEUE 1
#define NDIS_SWI 2
#define NDIS_PSTATE_RUNNING 1
#define NDIS_PSTATE_SLEEPING 2
__BEGIN_DECLS
extern int ndis_libinit(void);
extern int ndis_libfini(void);