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Commit ee28db84 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
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[PATCH] i4l: kernelcapi receive workqueue and locking rework 

From: Armin Schindler <armin@melware.de>

With this patch the ISDN kernel CAPI code uses a per application workqueue
with proper locking to prevent message re-ordering due to the fact a
workqueue may run on another CPU at the same time.  Also some locks for
internal data is added.

Removed global recv_queue work, use per application workqueue.  Added
proper locking mechanisms for application, controller and application
workqueue function.  Increased max.  number of possible applications and
controllers.
parent efffe9c8
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Showing with 75 additions and 32 deletions
drivers/isdn/capi/kcapi.c
View file @ ee28db84
/* $Id: kcapi.c,v 1.1.2.7 2004/03/16 08:01:47 armin Exp $
/* $Id: kcapi.c,v 1.1.2.8 2004/03/26 19:57:20 armin Exp $
*
* Kernel CAPI 2.0 Module
*
......@@ -31,7 +31,7 @@
#include <linux/b1lli.h>
#endif
static char *revision = "$Revision: 1.1.2.7 $";
static char *revision = "$Revision: 1.1.2.8 $";
/* ------------------------------------------------------------- */
......@@ -63,13 +63,13 @@ static char capi_manufakturer[64] = "AVM Berlin";
LIST_HEAD(capi_drivers);
rwlock_t capi_drivers_list_lock = RW_LOCK_UNLOCKED;
static rwlock_t application_lock = RW_LOCK_UNLOCKED;
static DECLARE_MUTEX(controller_sem);
struct capi20_appl *capi_applications[CAPI_MAXAPPL];
struct capi_ctr *capi_cards[CAPI_MAXCONTR];
static int ncards;
static struct sk_buff_head recv_queue;
static struct work_struct tq_recv_notify;
/* -------- controller ref counting -------------------------------------- */
......@@ -174,7 +174,7 @@ static void notify_up(u32 contr)
for (applid = 1; applid <= CAPI_MAXAPPL; applid++) {
ap = get_capi_appl_by_nr(applid);
if (ap && ap->callback)
if (ap && ap->callback && !ap->release_in_progress)
ap->callback(KCI_CONTRUP, contr, &card->profile);
}
}
......@@ -192,7 +192,7 @@ static void notify_down(u32 contr)
for (applid = 1; applid <= CAPI_MAXAPPL; applid++) {
ap = get_capi_appl_by_nr(applid);
if (ap && ap->callback)
if (ap && ap->callback && !ap->release_in_progress)
ap->callback(KCI_CONTRDOWN, contr, 0);
}
}
......@@ -237,38 +237,39 @@ static int notify_push(unsigned int cmd, u32 controller, u16 applid, u32 ncci)
/* -------- Receiver ------------------------------------------ */
static void recv_handler(void *dummy)
static void recv_handler(void *_ap)
{
struct sk_buff *skb;
struct capi20_appl *ap;
struct capi20_appl *ap = (struct capi20_appl *) _ap;
while ((skb = skb_dequeue(&recv_queue)) != 0) {
ap = get_capi_appl_by_nr(CAPIMSG_APPID(skb->data));
if (!ap) {
printk(KERN_ERR "kcapi: recv_handler: applid %d ? (%s)\n",
CAPIMSG_APPID(skb->data), capi_message2str(skb->data));
kfree_skb(skb);
continue;
}
if ((!ap) || (ap->release_in_progress))
return;
down(&ap->recv_sem);
while ((skb = skb_dequeue(&ap->recv_queue))) {
if (CAPIMSG_CMD(skb->data) == CAPI_DATA_B3_IND)
ap->nrecvdatapkt++;
else
ap->nrecvctlpkt++;
ap->recv_message(ap, skb);
}
up(&ap->recv_sem);
}
void capi_ctr_handle_message(struct capi_ctr * card, u16 appl, struct sk_buff *skb)
{
struct capi20_appl *ap;
int showctl = 0;
u8 cmd, subcmd;
unsigned long flags;
if (card->cardstate != CARD_RUNNING) {
printk(KERN_INFO "kcapi: controller %d not active, got: %s",
card->cnr, capi_message2str(skb->data));
goto error;
}
cmd = CAPIMSG_COMMAND(skb->data);
subcmd = CAPIMSG_SUBCOMMAND(skb->data);
if (cmd == CAPI_DATA_B3 && subcmd == CAPI_IND) {
......@@ -293,8 +294,19 @@ void capi_ctr_handle_message(struct capi_ctr * card, u16 appl, struct sk_buff *s
}
}
skb_queue_tail(&recv_queue, skb);
schedule_work(&tq_recv_notify);
read_lock_irqsave(&application_lock, flags);
ap = get_capi_appl_by_nr(CAPIMSG_APPID(skb->data));
if ((!ap) || (ap->release_in_progress)) {
read_unlock_irqrestore(&application_lock, flags);
printk(KERN_ERR "kcapi: handle_message: applid %d state released (%s)\n",
CAPIMSG_APPID(skb->data), capi_message2str(skb->data));
goto error;
}
skb_queue_tail(&ap->recv_queue, skb);
schedule_work(&ap->recv_work);
read_unlock_irqrestore(&application_lock, flags);
return;
error:
......@@ -310,11 +322,13 @@ void capi_ctr_ready(struct capi_ctr * card)
card->cardstate = CARD_RUNNING;
down(&controller_sem);
for (appl = 1; appl <= CAPI_MAXAPPL; appl++) {
ap = get_capi_appl_by_nr(appl);
if (!ap) continue;
if (!ap || ap->release_in_progress) continue;
register_appl(card, appl, &ap->rparam);
}
up(&controller_sem);
printk(KERN_NOTICE "kcapi: card %d \"%s\" ready.\n",
card->cnr, card->name);
......@@ -342,7 +356,7 @@ void capi_ctr_reseted(struct capi_ctr * card)
for (appl = 1; appl <= CAPI_MAXAPPL; appl++) {
struct capi20_appl *ap = get_capi_appl_by_nr(appl);
if (!ap)
if (!ap || ap->release_in_progress)
continue;
capi_ctr_put(card);
......@@ -382,16 +396,21 @@ attach_capi_ctr(struct capi_ctr *card)
{
int i;
down(&controller_sem);
for (i = 0; i < CAPI_MAXCONTR; i++) {
if (capi_cards[i] == NULL)
break;
}
if (i == CAPI_MAXCONTR) {
up(&controller_sem);
printk(KERN_ERR "kcapi: out of controller slots\n");
return -EBUSY;
}
capi_cards[i] = card;
up(&controller_sem);
card->nrecvctlpkt = 0;
card->nrecvdatapkt = 0;
card->nsentctlpkt = 0;
......@@ -480,18 +499,23 @@ u16 capi20_register(struct capi20_appl *ap)
{
int i;
u16 applid;
unsigned long flags;
DBG("");
if (ap->rparam.datablklen < 128)
return CAPI_LOGBLKSIZETOSMALL;
write_lock_irqsave(&application_lock, flags);
for (applid = 1; applid <= CAPI_MAXAPPL; applid++) {
if (capi_applications[applid - 1] == NULL)
break;
}
if (applid > CAPI_MAXAPPL)
if (applid > CAPI_MAXAPPL) {
write_unlock_irqrestore(&application_lock, flags);
return CAPI_TOOMANYAPPLS;
}
ap->applid = applid;
capi_applications[applid - 1] = ap;
......@@ -501,12 +525,21 @@ u16 capi20_register(struct capi20_appl *ap)
ap->nsentctlpkt = 0;
ap->nsentdatapkt = 0;
ap->callback = 0;
init_MUTEX(&ap->recv_sem);
skb_queue_head_init(&ap->recv_queue);
INIT_WORK(&ap->recv_work, recv_handler, (void *)ap);
ap->release_in_progress = 0;
write_unlock_irqrestore(&application_lock, flags);
down(&controller_sem);
for (i = 0; i < CAPI_MAXCONTR; i++) {
if (!capi_cards[i] || capi_cards[i]->cardstate != CARD_RUNNING)
continue;
register_appl(capi_cards[i], applid, &ap->rparam);
}
up(&controller_sem);
if (showcapimsgs & 1) {
printk(KERN_DEBUG "kcapi: appl %d up\n", applid);
}
......@@ -519,15 +552,26 @@ EXPORT_SYMBOL(capi20_register);
u16 capi20_release(struct capi20_appl *ap)
{
int i;
unsigned long flags;
DBG("applid %#x", ap->applid);
write_lock_irqsave(&application_lock, flags);
ap->release_in_progress = 1;
capi_applications[ap->applid - 1] = NULL;
write_unlock_irqrestore(&application_lock, flags);
down(&controller_sem);
for (i = 0; i < CAPI_MAXCONTR; i++) {
if (!capi_cards[i] || capi_cards[i]->cardstate != CARD_RUNNING)
continue;
release_appl(capi_cards[i], ap->applid);
}
capi_applications[ap->applid - 1] = NULL;
up(&controller_sem);
flush_scheduled_work();
skb_queue_purge(&ap->recv_queue);
if (showcapimsgs & 1) {
printk(KERN_DEBUG "kcapi: appl %d down\n", ap->applid);
}
......@@ -547,7 +591,7 @@ u16 capi20_put_message(struct capi20_appl *ap, struct sk_buff *skb)
if (ncards == 0)
return CAPI_REGNOTINSTALLED;
if (ap->applid == 0)
if ((ap->applid == 0) || ap->release_in_progress)
return CAPI_ILLAPPNR;
if (skb->len < 12
|| !capi_cmd_valid(CAPIMSG_COMMAND(skb->data))
......@@ -925,10 +969,6 @@ static int __init kcapi_init(void)
char *p;
char rev[32];
skb_queue_head_init(&recv_queue);
INIT_WORK(&tq_recv_notify, recv_handler, NULL);
kcapi_proc_init();
if ((p = strchr(revision, ':')) != 0 && p[1]) {
......
include/linux/kernelcapi.h
View file @ ee28db84
......@@ -10,10 +10,8 @@
#ifndef __KERNELCAPI_H__
#define __KERNELCAPI_H__
#include <linux/list.h>
#define CAPI_MAXAPPL 128 /* maximum number of applications */
#define CAPI_MAXCONTR 16 /* maximum number of controller */
#define CAPI_MAXAPPL 240 /* maximum number of applications */
#define CAPI_MAXCONTR 32 /* maximum number of controller */
#define CAPI_MAXDATAWINDOW 8
......@@ -47,6 +45,7 @@ typedef struct kcapi_carddef {
#ifdef __KERNEL__
#include <linux/list.h>
#include <linux/skbuff.h>
#define KCI_CONTRUP 0 /* arg: struct capi_profile */
......@@ -63,6 +62,10 @@ struct capi20_appl {
unsigned long nrecvdatapkt;
unsigned long nsentctlpkt;
unsigned long nsentdatapkt;
struct semaphore recv_sem;
struct sk_buff_head recv_queue;
struct work_struct recv_work;
int release_in_progress;
/* ugly hack to allow for notification of added/removed
* controllers. The Right Way (tm) is known. XXX
......
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