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.
---
25-akpm/drivers/isdn/capi/kcapi.c | 96 ++++++++++++++++++++++++++-----------
25-akpm/include/linux/kernelcapi.h | 11 ++--
2 files changed, 75 insertions(+), 32 deletions(-)
diff -puN drivers/isdn/capi/kcapi.c~i4l-kernelcapi-rework drivers/isdn/capi/kcapi.c
--- 25/drivers/isdn/capi/kcapi.c~i4l-kernelcapi-rework 2004-03-27 02:37:36.416819448 -0800
+++ 25-akpm/drivers/isdn/capi/kcapi.c 2004-03-27 02:37:36.422818536 -0800
@@ -1,4 +1,4 @@
-/* $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
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,
/* -------- 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
}
}
- 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 * ca
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 *
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 *
{
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->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_app
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]) {
diff -puN include/linux/kernelcapi.h~i4l-kernelcapi-rework include/linux/kernelcapi.h
--- 25/include/linux/kernelcapi.h~i4l-kernelcapi-rework 2004-03-27 02:37:36.417819296 -0800
+++ 25-akpm/include/linux/kernelcapi.h 2004-03-27 02:37:36.422818536 -0800
@@ -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
_