Gigaset: permit module unload

Fix the initialization and reference counting of the Gigaset driver modules
so that they can be unloaded when they are not actually in use.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Hansjoerg Lipp <hjlipp@web.de>
Cc: Greg KH <gregkh@suse.de>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 29 insertions, 76 deletions

diff --git a/drivers/isdn/gigaset/common.c b/drivers/isdn/gigaset/common.c
index f8f7d7e553bf..aacedec4986f 100644
--- a/drivers/isdn/gigaset/common.c
+++ b/drivers/isdn/gigaset/common.c
@@ -31,7 +31,6 @@ MODULE_PARM_DESC(debug, "debug level");
 /* driver state flags */
 #define VALID_MINOR	0x01
 #define VALID_ID	0x02
-#define ASSIGNED	0x04
 
 void gigaset_dbg_buffer(enum debuglevel level, const unsigned char *msg,
 			size_t len, const unsigned char *buf)
@@ -178,7 +177,7 @@ int gigaset_get_channel(struct bc_state *bcs)
 	unsigned long flags;
 
 	spin_lock_irqsave(&bcs->cs->lock, flags);
-	if (bcs->use_count) {
+	if (bcs->use_count || !try_module_get(bcs->cs->driver->owner)) {
 		gig_dbg(DEBUG_ANY, "could not allocate channel %d",
 			bcs->channel);
 		spin_unlock_irqrestore(&bcs->cs->lock, flags);
@@ -203,6 +202,7 @@ void gigaset_free_channel(struct bc_state *bcs)
 	}
 	--bcs->use_count;
 	bcs->busy = 0;
+	module_put(bcs->cs->driver->owner);
 	gig_dbg(DEBUG_ANY, "freed channel %d", bcs->channel);
 	spin_unlock_irqrestore(&bcs->cs->lock, flags);
 }
@@ -356,31 +356,28 @@ static struct cardstate *alloc_cs(struct gigaset_driver *drv)
 {
 	unsigned long flags;
 	unsigned i;
+	struct cardstate *cs;
 	struct cardstate *ret = NULL;
 
 	spin_lock_irqsave(&drv->lock, flags);
+	if (drv->blocked)
+		goto exit;
 	for (i = 0; i < drv->minors; ++i) {
-		if (!(drv->flags[i] & VALID_MINOR)) {
-			if (try_module_get(drv->owner)) {
-				drv->flags[i] = VALID_MINOR;
-				ret = drv->cs + i;
-			}
+		cs = drv->cs + i;
+		if (!(cs->flags & VALID_MINOR)) {
+			cs->flags = VALID_MINOR;
+			ret = cs;
 			break;
 		}
 	}
+exit:
 	spin_unlock_irqrestore(&drv->lock, flags);
 	return ret;
 }
 
 static void free_cs(struct cardstate *cs)
 {
-	unsigned long flags;
-	struct gigaset_driver *drv = cs->driver;
-	spin_lock_irqsave(&drv->lock, flags);
-	if (drv->flags[cs->minor_index] & VALID_MINOR)
-		module_put(drv->owner);
-	drv->flags[cs->minor_index] = 0;
-	spin_unlock_irqrestore(&drv->lock, flags);
+	cs->flags = 0;
 }
 
 static void make_valid(struct cardstate *cs, unsigned mask)
@@ -388,7 +385,7 @@ static void make_valid(struct cardstate *cs, unsigned mask)
 	unsigned long flags;
 	struct gigaset_driver *drv = cs->driver;
 	spin_lock_irqsave(&drv->lock, flags);
-	drv->flags[cs->minor_index] |= mask;
+	cs->flags |= mask;
 	spin_unlock_irqrestore(&drv->lock, flags);
 }
 
@@ -397,7 +394,7 @@ static void make_invalid(struct cardstate *cs, unsigned mask)
 	unsigned long flags;
 	struct gigaset_driver *drv = cs->driver;
 	spin_lock_irqsave(&drv->lock, flags);
-	drv->flags[cs->minor_index] &= ~mask;
+	cs->flags &= ~mask;
 	spin_unlock_irqrestore(&drv->lock, flags);
 }
 
@@ -893,10 +890,17 @@ error:
 }
 EXPORT_SYMBOL_GPL(gigaset_start);
 
-void gigaset_shutdown(struct cardstate *cs)
+/* gigaset_shutdown
+ * check if a device is associated to the cardstate structure and stop it
+ * return value: 0 if ok, -1 if no device was associated
+ */
+int gigaset_shutdown(struct cardstate *cs)
 {
 	mutex_lock(&cs->mutex);
 
+	if (!(cs->flags & VALID_MINOR))
+		return -1;
+
 	cs->waiting = 1;
 
 	if (!gigaset_add_event(cs, &cs->at_state, EV_SHUTDOWN, NULL, 0, NULL)) {
@@ -913,6 +917,7 @@ void gigaset_shutdown(struct cardstate *cs)
 
 exit:
 	mutex_unlock(&cs->mutex);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(gigaset_shutdown);
 
@@ -954,13 +959,11 @@ struct cardstate *gigaset_get_cs_by_id(int id)
 	list_for_each_entry(drv, &drivers, list) {
 		spin_lock(&drv->lock);
 		for (i = 0; i < drv->minors; ++i) {
-			if (drv->flags[i] & VALID_ID) {
-				cs = drv->cs + i;
-				if (cs->myid == id)
-					ret = cs;
-			}
-			if (ret)
+			cs = drv->cs + i;
+			if ((cs->flags & VALID_ID) && cs->myid == id) {
+				ret = cs;
 				break;
+			}
 		}
 		spin_unlock(&drv->lock);
 		if (ret)
@@ -983,10 +986,9 @@ void gigaset_debugdrivers(void)
 		spin_lock(&drv->lock);
 		for (i = 0; i < drv->minors; ++i) {
 			gig_dbg(DEBUG_DRIVER, "  index %u", i);
-			gig_dbg(DEBUG_DRIVER, "    flags 0x%02x",
-				drv->flags[i]);
 			cs = drv->cs + i;
 			gig_dbg(DEBUG_DRIVER, "    cardstate %p", cs);
+			gig_dbg(DEBUG_DRIVER, "    flags 0x%02x", cs->flags);
 			gig_dbg(DEBUG_DRIVER, "    minor_index %u",
 				cs->minor_index);
 			gig_dbg(DEBUG_DRIVER, "    driver %p", cs->driver);
@@ -1010,7 +1012,7 @@ static struct cardstate *gigaset_get_cs_by_minor(unsigned minor)
 			continue;
 		index = minor - drv->minor;
 		spin_lock(&drv->lock);
-		if (drv->flags[index] & VALID_MINOR)
+		if (drv->cs[index].flags & VALID_MINOR)
 			ret = drv->cs + index;
 		spin_unlock(&drv->lock);
 		if (ret)
@@ -1038,7 +1040,6 @@ void gigaset_freedriver(struct gigaset_driver *drv)
 	gigaset_if_freedriver(drv);
 
 	kfree(drv->cs);
-	kfree(drv->flags);
 	kfree(drv);
 }
 EXPORT_SYMBOL_GPL(gigaset_freedriver);
@@ -1080,12 +1081,8 @@ struct gigaset_driver *gigaset_initdriver(unsigned minor, unsigned minors,
 	if (!drv->cs)
 		goto error;
 
-	drv->flags = kmalloc(minors * sizeof *drv->flags, GFP_KERNEL);
-	if (!drv->flags)
-		goto error;
-
 	for (i = 0; i < minors; ++i) {
-		drv->flags[i] = 0;
+		drv->cs[i].flags = 0;
 		drv->cs[i].driver = drv;
 		drv->cs[i].ops = drv->ops;
 		drv->cs[i].minor_index = i;
@@ -1106,53 +1103,9 @@ error:
 }
 EXPORT_SYMBOL_GPL(gigaset_initdriver);
 
-/* For drivers without fixed assignment device<->cardstate (usb) */
-struct cardstate *gigaset_getunassignedcs(struct gigaset_driver *drv)
-{
-	unsigned long flags;
-	struct cardstate *cs = NULL;
-	unsigned i;
-
-	spin_lock_irqsave(&drv->lock, flags);
-	if (drv->blocked)
-		goto exit;
-	for (i = 0; i < drv->minors; ++i) {
-		if ((drv->flags[i] & VALID_MINOR) &&
-		    !(drv->flags[i] & ASSIGNED)) {
-			drv->flags[i] |= ASSIGNED;
-			cs = drv->cs + i;
-			break;
-		}
-	}
-exit:
-	spin_unlock_irqrestore(&drv->lock, flags);
-	return cs;
-}
-EXPORT_SYMBOL_GPL(gigaset_getunassignedcs);
-
-void gigaset_unassign(struct cardstate *cs)
-{
-	unsigned long flags;
-	unsigned *minor_flags;
-	struct gigaset_driver *drv;
-
-	if (!cs)
-		return;
-	drv = cs->driver;
-	spin_lock_irqsave(&drv->lock, flags);
-	minor_flags = drv->flags + cs->minor_index;
-	if (*minor_flags & VALID_MINOR)
-		*minor_flags &= ~ASSIGNED;
-	spin_unlock_irqrestore(&drv->lock, flags);
-}
-EXPORT_SYMBOL_GPL(gigaset_unassign);
-
 void gigaset_blockdriver(struct gigaset_driver *drv)
 {
-	unsigned long flags;
-	spin_lock_irqsave(&drv->lock, flags);
 	drv->blocked = 1;
-	spin_unlock_irqrestore(&drv->lock, flags);
 }
 EXPORT_SYMBOL_GPL(gigaset_blockdriver);