revert some code that appears to be causing crashes

git-svn-id: http://svn.digium.com/svn/zaptel/branches/1.2@2078 5390a7c7-147a-4af0-8ec9-7488f05a26cb

3 files changed, 64 insertions, 57 deletions

diff --git a/wctc4xxp/base.c b/wctc4xxp/base.c
index c98f2d3..f42c577 100644
--- a/wctc4xxp/base.c
+++ b/wctc4xxp/base.c
@@ -626,7 +626,7 @@ static int dte_operation(struct zt_transcoder_channel *ztc, int op)
 
 	switch (op) {
 	case ZT_TCOP_ALLOCATE:
-		if (ztc->chan_built)
+		if (ztc->flags.chan_built)
 			break;
 		down(&wc->chansem);
 		if (st->encoder)
@@ -638,7 +638,7 @@ static int dte_operation(struct zt_transcoder_channel *ztc, int op)
 				       st->timeslot_out_num, st->timeslot_in_num, &(st->chan_out_num),
 				       &(st->chan_in_num));
 		/* Mark this channel as built */
-		ztc->chan_built = 1;
+		ztc->flags.chan_built = 1;
 		ztc->built_fmts = zth->dstfmt | zth->srcfmt;
 		
 		/* Mark the channel complement (other half of encoder/decoder pair) as built */
@@ -646,7 +646,7 @@ static int dte_operation(struct zt_transcoder_channel *ztc, int op)
 			compl_ztc = &(wc->udecode->channels[st->timeslot_in_num >> 1]);
 		else
 			compl_ztc = &(wc->uencode->channels[st->timeslot_in_num >> 1]);
-		compl_ztc->chan_built = 1;
+		compl_ztc->flags.chan_built = 1;
 		compl_ztc->built_fmts = zth->dstfmt | zth->srcfmt;
 		compl_st = compl_ztc->pvt;
 		compl_st->chan_in_num = st->chan_out_num;
@@ -662,20 +662,20 @@ static int dte_operation(struct zt_transcoder_channel *ztc, int op)
 			compl_ztc = &(wc->uencode->channels[st->timeslot_in_num >> 1]);
 
 		/* If the channel complement (other half of the encoder/decoder pair) is not being used... */
-		if (!compl_ztc->busy) {
+		if (!compl_ztc->flags.busy) {
 			if (st->encoder)
 				destroy_channel(wc, st->chan_in_num, st->chan_out_num);
 			else
 				destroy_channel(wc, st->chan_out_num, st->chan_in_num);
 
 			/* Mark this channel as not built */
-			ztc->chan_built = 0;
+			ztc->flags.chan_built = 0;
 			ztc->built_fmts = 0;
 			st->chan_in_num = 999;
 			st->chan_out_num = 999;
 			
 			/* Mark the channel complement as not built */
-			compl_ztc->chan_built = 0;
+			compl_ztc->flags.chan_built = 0;
 			compl_ztc->built_fmts = 0;
 			compl_st = compl_ztc->pvt;
 			compl_st->chan_in_num = 999;
@@ -1509,8 +1509,10 @@ static int __devinit init_one(struct pci_dev *pdev, const struct pci_device_id *
 		wc->udecode->channels[x].pvt = &decoders[x];
 	}
 	
-	zt_transcoder_register(wc->uencode, THIS_MODULE);
-	zt_transcoder_register(wc->udecode, THIS_MODULE);
+	wc->uencode->owner = wc->udecode->owner = THIS_MODULE;
+
+	zt_transcoder_register(wc->uencode);
+	zt_transcoder_register(wc->udecode);
 	
 	/* Enable bus mastering */
 	pci_set_master(pdev);
diff --git a/zaptel.h b/zaptel.h
index c974963..5434af3 100644
--- a/zaptel.h
+++ b/zaptel.h
@@ -49,7 +49,6 @@
 #endif
 
 #include <linux/fs.h>
-#include <linux/list.h>
 
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
 #define LINUX26
@@ -709,7 +708,7 @@ struct zt_transcode_header {
 
 	__u32 magic;		/* Magic value -- ZT_TRANSCODE_MAGIC, read by user */
 	__u32 config;		/* Read/write by user */
-	__u32 busy:1;		/* Read/write by user */
+ 	__u32 busy:1;		/* Read/write by user */
 	__u8 userhdr[ZT_TRANSCODE_HDRLEN - (sizeof(__u32) * 10)];	/* Storage for user parameters */
 	__u8 srcdata[ZT_TRANSCODE_BUFSIZ / 2];	/* Storage of source data */
 	__u8 dstdata[ZT_TRANSCODE_BUFSIZ / 2];	/* Storage of destination data */
@@ -1379,19 +1378,20 @@ struct zt_transcoder_channel {
 	wait_queue_head_t ready;
 	int errorstatus;
 	int offset;
-	unsigned int chan_built:1;
-	unsigned int have_reference:1;
-	unsigned int busy:1;
-	unsigned int transient:1;
+	struct {
+		unsigned int chan_built:1;
+		unsigned int busy:1;
+		unsigned int transient:1;
+		unsigned int have_reference:1;
+	} flags;
 	unsigned int built_fmts;
-	unsigned int flags;
 	unsigned int srcfmt;
 	unsigned int dstfmt;
 	struct zt_transcode_header *tch;
 };
 
 struct zt_transcoder {
-	struct list_head list;
+	struct zt_transcoder *next;
 	struct module *owner;
 	char name[80];
 	int numchannels;
@@ -1456,7 +1456,7 @@ struct zt_transcoder *zt_transcoder_alloc(int numchans);
 void zt_transcoder_free(struct zt_transcoder *ztc);
 
 /* Register a transcoder */
-int zt_transcoder_register(struct zt_transcoder *tc, struct module *owner);
+int zt_transcoder_register(struct zt_transcoder *tc);
 
 /* Unregister a transcoder */
 int zt_transcoder_unregister(struct zt_transcoder *tc);
diff --git a/zttranscode.c b/zttranscode.c
index aad71cc..39e84ae 100644
--- a/zttranscode.c
+++ b/zttranscode.c
@@ -47,7 +47,7 @@
 #endif
 
 static int debug = 0;
-static LIST_HEAD(trans);
+static struct zt_transcoder *trans;
 static spinlock_t translock = SPIN_LOCK_UNLOCKED;
 
 EXPORT_SYMBOL(zt_transcoder_register);
@@ -68,12 +68,11 @@ struct zt_transcoder *zt_transcoder_alloc(int numchans)
 	memset(ztc, 0, size);
 	strcpy(ztc->name, "<unspecified>");
 	ztc->numchannels = numchans;
-	INIT_LIST_HEAD(&ztc->list);
 	for (x=0;x<ztc->numchannels;x++) {
 		init_waitqueue_head(&ztc->channels[x].ready);
 		ztc->channels[x].parent = ztc;
 		ztc->channels[x].offset = x;
-		ztc->channels[x].chan_built = 0;
+		ztc->channels[x].flags.chan_built = 0;
 		ztc->channels[x].built_fmts = 0;
 	}
 
@@ -104,50 +103,58 @@ void zt_transcoder_free(struct zt_transcoder *ztc)
 	kfree(ztc);
 }
 
-int zt_transcoder_register(struct zt_transcoder *tc, struct module *owner)
+/* Register a transcoder */
+int zt_transcoder_register(struct zt_transcoder *tc)
 {
 	struct zt_transcoder *cur;
+	int res = -EBUSY;
 
 	spin_lock(&translock);
-	list_for_each_entry(cur, &trans, list) {
+	for (cur = trans; cur; cur = cur->next) {
 		if (cur == tc) {
 			spin_unlock(&translock);
-			return -EBUSY;
+			return res;
 		}
 	}
 
-	tc->owner = owner;
-	list_add(&tc->list, &trans);
+	tc->next = trans;
+	trans = tc;
 	printk("Registered codec translator '%s' with %d transcoders (srcs=%08x, dsts=%08x)\n", 
 	       tc->name, tc->numchannels, tc->srcfmts, tc->dstfmts);
+	res = 0;
 	spin_unlock(&translock);
 
-	return 0;
+	return res;
 }
 
 /* Unregister a transcoder */
 int zt_transcoder_unregister(struct zt_transcoder *tc) 
 {
-	struct zt_transcoder *cur, *next;
+	struct zt_transcoder *cur, *prev;
+	int res = -EINVAL;
 
 	spin_lock(&translock);
-	list_for_each_entry_safe(cur, next, &trans, list) {
-		if (cur == tc) {
-			list_del_init(&cur->list);
+	for (cur = trans, prev = NULL; cur; prev = cur, cur = cur->next) {
+		if (cur == tc)
 			break;
-		}
 	}
 
 	if (!cur) {
 		spin_unlock(&translock);
-		return -EINVAL;
+		return res;
 	}
 
+	if (prev)
+		prev->next = tc->next;
+	else
+		trans = tc->next;
+	tc->next = NULL;
 	printk("Unregistered codec translator '%s' with %d transcoders (srcs=%08x, dsts=%08x)\n", 
 	       tc->name, tc->numchannels, tc->srcfmts, tc->dstfmts);
+	res = 0;
 	spin_unlock(&translock);
 
-	return 0;
+	return res;
 }
 
 /* Alert a transcoder */
@@ -178,8 +185,7 @@ static int zt_tc_open(struct inode *inode, struct file *file)
 	
 	memset(ztc, 0, sizeof(*ztc));
 	memset(zth, 0, sizeof(*zth));
-	ztc->transient = 1;
-	ztc->busy = 1;
+	ztc->flags.transient = ztc->flags.busy = 1;
 	ztc->tch = zth;
 	if (debug)
 		printk("Allocated Transcoder Channel, header is at %p!\n", zth);
@@ -201,7 +207,7 @@ static void ztc_release(struct zt_transcoder_channel *ztc)
 	if (!ztc)
 		return;
 
-	ztc->busy = 0;
+	ztc->flags.busy = 0;
 
 	if (ztc->tch) {
 		for (page = virt_to_page(zth);
@@ -213,12 +219,12 @@ static void ztc_release(struct zt_transcoder_channel *ztc)
 
 	ztc->tch = NULL;
 
-	if (ztc->have_reference) {
+	if (ztc->flags.have_reference) {
 		module_put(ztc->parent->owner);
-		ztc->have_reference = 0;
+		ztc->flags.have_reference = 0;
 	}
 
-	if (ztc->transient);
+	if (ztc->flags.transient)
 		kfree(ztc);
 
 	if (debug)
@@ -244,7 +250,7 @@ static int do_allocate(struct zt_transcoder_channel **ztc)
 	    ((*ztc)->dstfmt != zth->dstfmt)) {
 		/* Find new transcoder */
 		spin_lock(&translock);
-		list_for_each_entry(tc, &trans, list) {
+		for (tc = trans; tc && !newztc; tc = tc->next) {
 			if (!(tc->srcfmts & zth->srcfmt))
 				continue;
 
@@ -253,10 +259,9 @@ static int do_allocate(struct zt_transcoder_channel **ztc)
 
 			match = 1;
 			for (x = 0; x < tc->numchannels; x++) {
-				if (tc->channels[x].busy)
+				if (tc->channels[x].flags.busy)
 					continue;
-
-				if (tc->channels[x].chan_built &&
+				if (tc->channels[x].flags.chan_built &&
 				    ((zth->srcfmt | zth->dstfmt) != tc->channels[x].built_fmts))
 					continue;
 
@@ -264,8 +269,7 @@ static int do_allocate(struct zt_transcoder_channel **ztc)
 					continue;
 
 				newztc = &tc->channels[x];
-				newztc->busy = 1;
-				newztc->have_reference = 1;
+				newztc->flags.busy = 1;
 				break;
 			}
 		}
@@ -279,7 +283,14 @@ static int do_allocate(struct zt_transcoder_channel **ztc)
 		(*ztc) = newztc;
 		(*ztc)->tch = origztc->tch;
 		origztc->tch = NULL;
-		(*ztc)->transient = 0;
+		/* ensure that the 'busy' flag doesn't get cleared,
+		   even for a short time, so no other thread will
+		   grab this channel
+		*/
+		origztc->flags.busy = 1;
+		(*ztc)->flags = origztc->flags;
+		(*ztc)->flags.transient = 0;
+		(*ztc)->flags.have_reference = 1;
 		ztc_release(origztc);
 	}
 
@@ -295,7 +306,7 @@ static int wait_busy(struct zt_transcoder_channel *ztc)
 	int ret;
 
 	for (;;) {
-		if (!(ztc->tch->busy))
+		if (!ztc->tch->busy)
 			return 0;
 		if ((ret = schluffen(&ztc->ready)))
 			return ret;
@@ -312,16 +323,10 @@ static int zt_tc_getinfo(unsigned long data)
 		return -EFAULT;
 
 	spin_lock(&translock);
-	x = info.tcnum;
-	list_for_each_entry(tc, &trans, list) {
-		if (!x)
-			break;
-		else
-			x--;
-	}
+	for (tc = trans, x = info.tcnum; tc && x; tc = tc->next, x--);
 	spin_unlock(&translock);
 
-	if (x || !tc)
+	if (!tc)
 		return -ENOSYS;
 
 	strncpy(info.name, tc->name, sizeof(info.name) - 1);
@@ -357,9 +362,9 @@ static int zt_tc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 		break;
 	case ZT_TCOP_RELEASE:
 		ret = ztc->parent->operation(ztc, ZT_TCOP_RELEASE);
-		if (ztc->have_reference) {
+		if (ztc->flags.have_reference) {
 			module_put(ztc->parent->owner);
-			ztc->have_reference = 0;
+			ztc->flags.have_reference = 0;
 		}
 		break;
 	case ZT_TCOP_TRANSCODE: