From 8239ad02390c0feec4c726160b7519f04caf25b9 Mon Sep 17 00:00:00 2001
From: markster <markster@5390a7c7-147a-4af0-8ec9-7488f05a26cb>
Date: Mon, 16 Aug 2004 17:27:12 +0000
Subject: Merge Paul Cadach's TDMoE fixes for using tasklet (Thanks!)

git-svn-id: http://svn.digium.com/svn/zaptel/trunk@450 5390a7c7-147a-4af0-8ec9-7488f05a26cb
---
 ztdynamic.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 69 insertions(+), 4 deletions(-)

(limited to 'ztdynamic.c')

diff --git a/ztdynamic.c b/ztdynamic.c
index 90aa4fa..3515e16 100755
--- a/ztdynamic.c
+++ b/ztdynamic.c
@@ -31,6 +31,7 @@
 #include <linux/slab.h>
 #include <linux/kmod.h>
 #include <linux/sched.h>
+#include <linux/interrupt.h>
 #ifdef CONFIG_DEVFS_FS
 #include <linux/devfs_fs_kernel.h>
 #endif
@@ -40,6 +41,16 @@
 #include <linux/zaptel.h>
 #endif
 
+/*
+ * Tasklets provide better system interactive response at the cost of the
+ * possibility of losing a frame of data at very infrequent intervals.  If
+ * you are more concerned with the performance of your machine, enable the
+ * tasklets.  If you are strict about absolutely no drops, then do not enable
+ * tasklets.
+ */
+
+#define ENABLE_TASKLETS
+
 /*
  *  Dynamic spans implemented using TDM over X with standard message
  *  types.  Message format is as follows:
@@ -74,6 +85,18 @@ EXPORT_SYMBOL(zt_dynamic_register);
 EXPORT_SYMBOL(zt_dynamic_unregister);
 EXPORT_SYMBOL(zt_dynamic_receive);
 
+#ifdef ENABLE_TASKLETS
+static int taskletrun;
+static int taskletsched;
+static int taskletpending;
+static int taskletexec;
+static int txerrors;
+static struct tasklet_struct ztd_tlet;
+
+static void ztd_tasklet(unsigned long data);
+#endif
+
+
 static struct zt_dynamic {
 	char addr[40];
 	char dname[20];
@@ -189,15 +212,15 @@ static void ztd_sendmessage(struct zt_dynamic *z)
 	
 	for (x=0;x<z->span.channels;x++) {
 		memcpy(buf, z->chans[x].writechunk, ZT_CHUNKSIZE);
-		buf += 8;
-		msglen += 8;
+		buf += ZT_CHUNKSIZE;
+		msglen += ZT_CHUNKSIZE;
 	}
 	
 	z->driver->transmit(z->pvt, z->msgbuf, msglen);
 	
 }
 
-static void ztdynamic_run(void)
+static void __ztdynamic_run(void)
 {
 	unsigned long flags;
 	struct zt_dynamic *z;
@@ -221,6 +244,21 @@ static void ztdynamic_run(void)
 	spin_unlock_irqrestore(&dlock, flags);
 }
 
+#ifdef ENABLE_TASKLETS
+static void ztdynamic_run(void)
+{
+	if (!taskletpending) {
+		taskletpending = 1;
+		taskletsched++;
+		tasklet_hi_schedule(&ztd_tlet);
+	} else {
+		txerrors++;
+	}
+}
+#else
+#define ztdynamic_run __ztdynamic_run
+#endif
+
 void zt_dynamic_receive(struct zt_span *span, unsigned char *msg, int msglen)
 {
 	struct zt_dynamic *ztd = span->pvt;
@@ -409,6 +447,12 @@ static int destroy_dynamic(ZT_DYNAMIC_SPAN *zds)
 		spin_unlock_irqrestore(&dlock, flags);
 		return -EINVAL;
 	}
+	/* Don't destroy span until it is in use */
+	if (z->usecount) {
+		spin_unlock_irqrestore(&dlock, flags);
+		printk("Attempt to destroy dynamic span while it is in use\n");
+		return -EBUSY;
+	}
 	/* Unlink it */
 	cur = dspans;
 	while(cur) {
@@ -563,7 +607,7 @@ static int create_dynamic(ZT_DYNAMIC_SPAN *zds)
 		spin_unlock_irqrestore(&dlock, flags);
 		sprintf(fn, "ztd-%s", zds->driver);
 		request_module(fn);
-		spin_unlock_irqrestore(&dlock, flags);
+		spin_lock_irqsave(&dlock, flags);
 		ztd = find_driver(zds->driver);
 	}
 	spin_unlock_irqrestore(&dlock, flags);
@@ -608,6 +652,18 @@ static int create_dynamic(ZT_DYNAMIC_SPAN *zds)
 
 }
 
+#ifdef ENABLE_TASKLETS
+static void ztd_tasklet(unsigned long data)
+{
+	taskletrun++;
+	if (taskletpending) {
+		taskletexec++;
+		__ztdynamic_run();
+	}
+	taskletpending = 0;
+}
+#endif
+
 static int ztdynamic_ioctl(unsigned int cmd, unsigned long data)
 {
 	ZT_DYNAMIC_SPAN zds;
@@ -741,12 +797,21 @@ int ztdynamic_init(void)
 	alarmcheck.function = check_for_red_alarm;
 	/* Check once per second */
 	mod_timer(&alarmcheck, jiffies + 1 * HZ);
+#ifdef ENABLE_TASKLETS
+	tasklet_init(&ztd_tlet, ztd_tasklet, 0);
+#endif
 	printk("Zaptel Dynamic Span support LOADED\n");
 	return 0;
 }
 
 void ztdynamic_cleanup(void)
 {
+#ifdef ENABLE_TASKLETS
+	if (taskletpending) {
+		tasklet_disable(&ztd_tlet);
+		tasklet_kill(&ztd_tlet);
+	}
+#endif
 	zt_set_dynamic_ioctl(NULL);
 	del_timer(&alarmcheck);
 	printk("Zaptel Dynamic Span support unloaded\n");
-- 
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