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new ca_flush_io() mechanism prevents deadlock when they call

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ca_flush_io() from within an event routine. Also forces early
transmission of leading search UDP frames.
This commit is contained in:
Jeff Hill
1995-10-12 01:30:10 +00:00
parent e62f7d0ae2
commit b782f63a7d
1 changed files with 46 additions and 49 deletions
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95
src/ca/access.c
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@@ -99,6 +99,11 @@
/************************************************************************/
/*
* $Log$
* Revision 1.78 1995/09/29 21:47:33 jhill
* alignment fix for SPARC IOC client and changes to prevent running of
* access rights or connection handlers when the connection is lost just
* after deleting a channel
*
* Revision 1.77 1995/09/01 14:31:32 mrk
* Fixed bug causing memory problem
*
@@ -576,6 +581,8 @@ int ca_os_independent_init (void)
ca_spawn_repeater();
}
ca_static->ca_flush_pending = FALSE;
return ECA_NORMAL;
}
@@ -2682,18 +2689,16 @@ void clearChannelResources(unsigned id)
/* if the argument early is specified TRUE then CA_NORMAL is */
/* returned early (prior to timeout experation) when outstanding */
/* IO completes. */
/* ca_flush_io() is called by this routine. */
/* Output buffers are flushed by this routine */
/************************************************************************/
int epicsShareAPI ca_pend (ca_real timeout, int early)
{
struct timeval beg_time;
ca_real delay;
struct timeval tmo;
INITCHK;
if(timeout<0.0){
return ECA_TIMEOUT;
}
if(EVENTLOCKTEST){
return ECA_EVDISALLOW;
@@ -2706,19 +2711,37 @@ int epicsShareAPI ca_pend (ca_real timeout, int early)
* (guarantees that we wait for all send buffer to be
* flushed even if this requires blocking)
*/
ca_flush_io();
ca_static->ca_flush_pending = TRUE;
if(pndrecvcnt<1 && early){
/*
* force the flush
*/
LD_CA_TIME (0.0, &tmo);
cac_mux_io(&tmo);
return ECA_NORMAL;
}
if(timeout<0.0){
/*
* force the flush
*/
LD_CA_TIME (0.0, &tmo);
cac_mux_io(&tmo);
return ECA_TIMEOUT;
}
beg_time = ca_static->currentTime;
delay = 0.0;
while(TRUE){
ca_real remaining;
struct timeval tmo;
if (pndrecvcnt<1 && early) {
/*
* force the flush
*/
LD_CA_TIME (0.0, &tmo);
cac_mux_io(&tmo);
return ECA_NORMAL;
}
@@ -2749,14 +2772,16 @@ int epicsShareAPI ca_pend (ca_real timeout, int early)
if (remaining <= (1.0/USEC_PER_SEC)) {
if(early){
ca_pend_io_cleanup();
ca_flush_io();
ca_static->ca_flush_pending = TRUE;
}
/*
* be certain that we processed
* recv backlog at least once
*/
tmo.tv_sec = 0L;
tmo.tv_usec = 0L;
/*
* force the flush
*/
LD_CA_TIME (0.0, &tmo);
cac_block_for_io_completion (&tmo);
return ECA_TIMEOUT;
}
@@ -2864,55 +2889,27 @@ LOCAL void ca_pend_io_cleanup()
/*
* CA_FLUSH_IO()
*
* reprocess connection state and
* flush the send buffer
*
*/
int epicsShareAPI ca_flush_io()
{
struct ioc_in_use *piiu;
struct timeval timeout;
unsigned long bytesPending;
INITCHK;
while (TRUE) {
int pending;
/*
* force early transmission of the first few search frames
*/
manage_conn(TRUE);
/*
* wait for all buffers to flush
*/
pending = FALSE;
LOCK;
for( piiu = (IIU *) iiuList.node.next;
piiu;
piiu = (IIU *) piiu->node.next){
if(piiu == piiuCast || piiu->conn_up == FALSE){
continue;
}
bytesPending = cacRingBufferReadSize(
&piiu->send,
FALSE);
if(bytesPending != 0){
pending = TRUE;
}
}
UNLOCK;
if (!pending) {
break;
}
/*
* perform socket io
* and process recv backlog
*/
LD_CA_TIME (SELECT_POLL, &timeout);
cac_mux_io (&timeout);
}
/*
* Wait for all send buffers to be flushed
* while performing socket io and processing recv backlog
*/
ca_static->ca_flush_pending = TRUE;
LD_CA_TIME (0.0, &timeout);
cac_mux_io (&timeout);
return ECA_NORMAL;
}