CAPI: Rework capi_ctr_ready/down

This step prepares the application of proper controller locking: Push
all state changing work into the notify handler that are called by
capi_ctr_ready and capi_ctr_down, switch detach_capi_ctr to issue a
synchronous ctr_down. Also ensure that we do not go through any action
if the state did not change.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/isdn/capi/kcapi.c

@@ -169,42 +169,72 @@ static void release_appl(struct capi_ctr *ctr, u16 applid)
 
 static void notify_up(u32 contr)
 {
-	struct capi_ctr *ctr = get_capi_ctr_by_nr(contr);
 	struct capi20_appl *ap;
+	struct capi_ctr *ctr;
 	u16 applid;
 
-	if (showcapimsgs & 1) {
+	if (showcapimsgs & 1)
 	        printk(KERN_DEBUG "kcapi: notify up contr %d\n", contr);
-	}
-	if (!ctr) {
-		printk(KERN_WARNING "%s: invalid contr %d\n", __func__, contr);
+
+	ctr = get_capi_ctr_by_nr(contr);
+	if (ctr) {
+		if (ctr->state == CAPI_CTR_RUNNING)
 			return;
-	}
+
+		ctr->state = CAPI_CTR_RUNNING;
+
 		for (applid = 1; applid <= CAPI_MAXAPPL; applid++) {
 			ap = get_capi_appl_by_nr(applid);
-		if (!ap || ap->release_in_progress) continue;
+			if (!ap || ap->release_in_progress)
+				continue;
 			register_appl(ctr, applid, &ap->rparam);
 			if (ap->callback && !ap->release_in_progress)
-			ap->callback(KCI_CONTRUP, contr, &ctr->profile);
+				ap->callback(KCI_CONTRUP, contr,
+					     &ctr->profile);
 		}
+	} else
+		printk(KERN_WARNING "%s: invalid contr %d\n", __func__, contr);
 }
 
 /* -------- KCI_CONTRDOWN ------------------------------------- */
 
-static void notify_down(u32 contr)
+static void ctr_down(struct capi_ctr *ctr)
 {
 	struct capi20_appl *ap;
 	u16 applid;
 
-	if (showcapimsgs & 1) {
-        	printk(KERN_DEBUG "kcapi: notify down contr %d\n", contr);
-	}
+	if (ctr->state == CAPI_CTR_DETECTED)
+		return;
+
+	ctr->state = CAPI_CTR_DETECTED;
+
+	memset(ctr->manu, 0, sizeof(ctr->manu));
+	memset(&ctr->version, 0, sizeof(ctr->version));
+	memset(&ctr->profile, 0, sizeof(ctr->profile));
+	memset(ctr->serial, 0, sizeof(ctr->serial));
 
 	for (applid = 1; applid <= CAPI_MAXAPPL; applid++) {
 		ap = get_capi_appl_by_nr(applid);
-		if (ap && ap->callback && !ap->release_in_progress)
-			ap->callback(KCI_CONTRDOWN, contr, NULL);
+		if (ap && !ap->release_in_progress) {
+			if (ap->callback)
+				ap->callback(KCI_CONTRDOWN, ctr->cnr, NULL);
+			capi_ctr_put(ctr);
 		}
+	}
+}
+
+static void notify_down(u32 contr)
+{
+	struct capi_ctr *ctr;
+
+	if (showcapimsgs & 1)
+		printk(KERN_DEBUG "kcapi: notify down contr %d\n", contr);
+
+	ctr = get_capi_ctr_by_nr(contr);
+	if (ctr)
+		ctr_down(ctr);
+	else
+		printk(KERN_WARNING "%s: invalid contr %d\n", __func__, contr);
 }
 
 static void notify_handler(struct work_struct *work)
@@ -368,8 +398,6 @@ EXPORT_SYMBOL(capi_ctr_handle_message);
 
 void capi_ctr_ready(struct capi_ctr *ctr)
 {
-	ctr->state = CAPI_CTR_RUNNING;
-
 	printk(KERN_NOTICE "kcapi: controller [%03d] \"%s\" ready.\n",
 	       ctr->cnr, ctr->name);
 
@@ -388,28 +416,6 @@ EXPORT_SYMBOL(capi_ctr_ready);
 
 void capi_ctr_down(struct capi_ctr *ctr)
 {
-	u16 appl;
-
-	DBG("");
-
-	if (ctr->state == CAPI_CTR_DETECTED)
-		return;
-
-	ctr->state = CAPI_CTR_DETECTED;
-
-	memset(ctr->manu, 0, sizeof(ctr->manu));
-	memset(&ctr->version, 0, sizeof(ctr->version));
-	memset(&ctr->profile, 0, sizeof(ctr->profile));
-	memset(ctr->serial, 0, sizeof(ctr->serial));
-
-	for (appl = 1; appl <= CAPI_MAXAPPL; appl++) {
-		struct capi20_appl *ap = get_capi_appl_by_nr(appl);
-		if (!ap || ap->release_in_progress)
-			continue;
-
-		capi_ctr_put(ctr);
-	}
-
 	printk(KERN_NOTICE "kcapi: controller [%03d] down.\n", ctr->cnr);
 
 	notify_push(KCI_CONTRDOWN, ctr->cnr, 0, 0);
@@ -513,8 +519,7 @@ EXPORT_SYMBOL(attach_capi_ctr);
 
 int detach_capi_ctr(struct capi_ctr *ctr)
 {
-	if (ctr->state != CAPI_CTR_DETECTED)
-		capi_ctr_down(ctr);
+	ctr_down(ctr);
 
 	ncontrollers--;