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>

5 files changed, 85 insertions, 142 deletions

diff --git a/drivers/isdn/gigaset/bas-gigaset.c b/drivers/isdn/gigaset/bas-gigaset.c
index 7c905305406b..5255b5e20e13 100644
--- a/drivers/isdn/gigaset/bas-gigaset.c
+++ b/drivers/isdn/gigaset/bas-gigaset.c
@@ -134,7 +134,6 @@ struct bas_cardstate {
 
 
 static struct gigaset_driver *driver = NULL;
-static struct cardstate *cardstate = NULL;
 
 /* usb specific object needed to register this driver with the usb subsystem */
 static struct usb_driver gigaset_usb_driver = {
@@ -2247,11 +2246,11 @@ static int gigaset_probe(struct usb_interface *interface,
                  __func__, le16_to_cpu(udev->descriptor.idVendor),
                  le16_to_cpu(udev->descriptor.idProduct));
 
-        cs = gigaset_getunassignedcs(driver);
-        if (!cs) {
-                dev_err(&udev->dev, "no free cardstate\n");
+        /* allocate memory for our device state and intialize it */
+        cs = gigaset_initcs(driver, BAS_CHANNELS, 0, 0, cidmode,
+                            GIGASET_MODULENAME);
+        if (!cs)
                 return -ENODEV;
-        }
         ucs = cs->hw.bas;
 
         /* save off device structure ptrs for later use */
@@ -2320,7 +2319,7 @@ allocerr:
 error:
         freeurbs(cs);
         usb_set_intfdata(interface, NULL);
-        gigaset_unassign(cs);
+        gigaset_freecs(cs);
         return -ENODEV;
 }
 
@@ -2362,7 +2361,7 @@ static void gigaset_disconnect(struct usb_interface *interface)
         ucs->interface = NULL;
         ucs->udev = NULL;
         cs->dev = NULL;
-        gigaset_unassign(cs);
+        gigaset_freecs(cs);
 }
 
 /* gigaset_suspend
@@ -2501,12 +2500,6 @@ static int __init bas_gigaset_init(void)
                                        &gigops, THIS_MODULE)) == NULL)
                 goto error;
 
-        /* allocate memory for our device state and intialize it */
-        cardstate = gigaset_initcs(driver, BAS_CHANNELS, 0, 0, cidmode,
-                                   GIGASET_MODULENAME);
-        if (!cardstate)
-                goto error;
-
         /* register this driver with the USB subsystem */
         result = usb_register(&gigaset_usb_driver);
         if (result < 0) {
@@ -2518,9 +2511,7 @@ static int __init bas_gigaset_init(void)
         info(DRIVER_DESC);
         return 0;
 
-error:  if (cardstate)
-                gigaset_freecs(cardstate);
-        cardstate = NULL;
+error:
         if (driver)
                 gigaset_freedriver(driver);
         driver = NULL;
@@ -2532,43 +2523,50 @@ error:	if (cardstate)
  */
 static void __exit bas_gigaset_exit(void)
 {
-        struct bas_cardstate *ucs = cardstate->hw.bas;
+        struct bas_cardstate *ucs;
+        int i;
 
         gigaset_blockdriver(driver); /* => probe will fail
                                       * => no gigaset_start any more
                                       */
 
-        gigaset_shutdown(cardstate);
-        /* from now on, no isdn callback should be possible */
-
-        /* close all still open channels */
-        if (ucs->basstate & BS_B1OPEN) {
-                gig_dbg(DEBUG_INIT, "closing B1 channel");
-                usb_control_msg(ucs->udev, usb_sndctrlpipe(ucs->udev, 0),
-                                HD_CLOSE_B1CHANNEL, OUT_VENDOR_REQ, 0, 0,
-                                NULL, 0, BAS_TIMEOUT);
-        }
-        if (ucs->basstate & BS_B2OPEN) {
-                gig_dbg(DEBUG_INIT, "closing B2 channel");
-                usb_control_msg(ucs->udev, usb_sndctrlpipe(ucs->udev, 0),
-                                HD_CLOSE_B2CHANNEL, OUT_VENDOR_REQ, 0, 0,
-                                NULL, 0, BAS_TIMEOUT);
-        }
-        if (ucs->basstate & BS_ATOPEN) {
-                gig_dbg(DEBUG_INIT, "closing AT channel");
-                usb_control_msg(ucs->udev, usb_sndctrlpipe(ucs->udev, 0),
-                                HD_CLOSE_ATCHANNEL, OUT_VENDOR_REQ, 0, 0,
-                                NULL, 0, BAS_TIMEOUT);
+        /* stop all connected devices */
+        for (i = 0; i < driver->minors; i++) {
+                if (gigaset_shutdown(driver->cs + i) < 0)
+                        continue;               /* no device */
+                /* from now on, no isdn callback should be possible */
+
+                /* close all still open channels */
+                ucs = driver->cs[i].hw.bas;
+                if (ucs->basstate & BS_B1OPEN) {
+                        gig_dbg(DEBUG_INIT, "closing B1 channel");
+                        usb_control_msg(ucs->udev,
+                                        usb_sndctrlpipe(ucs->udev, 0),
+                                        HD_CLOSE_B1CHANNEL, OUT_VENDOR_REQ,
+                                        0, 0, NULL, 0, BAS_TIMEOUT);
+                }
+                if (ucs->basstate & BS_B2OPEN) {
+                        gig_dbg(DEBUG_INIT, "closing B2 channel");
+                        usb_control_msg(ucs->udev,
+                                        usb_sndctrlpipe(ucs->udev, 0),
+                                        HD_CLOSE_B2CHANNEL, OUT_VENDOR_REQ,
+                                        0, 0, NULL, 0, BAS_TIMEOUT);
+                }
+                if (ucs->basstate & BS_ATOPEN) {
+                        gig_dbg(DEBUG_INIT, "closing AT channel");
+                        usb_control_msg(ucs->udev,
+                                        usb_sndctrlpipe(ucs->udev, 0),
+                                        HD_CLOSE_ATCHANNEL, OUT_VENDOR_REQ,
+                                        0, 0, NULL, 0, BAS_TIMEOUT);
+                }
+                ucs->basstate = 0;
         }
-        ucs->basstate = 0;
 
         /* deregister this driver with the USB subsystem */
         usb_deregister(&gigaset_usb_driver);
         /* this will call the disconnect-callback */
         /* from now on, no disconnect/probe callback should be running */
 
-        gigaset_freecs(cardstate);
-        cardstate = NULL;
         gigaset_freedriver(driver);
         driver = NULL;
 }
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);
 
diff --git a/drivers/isdn/gigaset/gigaset.h b/drivers/isdn/gigaset/gigaset.h
index 92986a5d4055..f365993161fc 100644
--- a/drivers/isdn/gigaset/gigaset.h
+++ b/drivers/isdn/gigaset/gigaset.h
@@ -435,6 +435,7 @@ struct cardstate {
         unsigned minor_index;
         struct device *dev;
         struct device *tty_dev;
+        unsigned flags;
 
         const struct gigaset_ops *ops;
 
@@ -539,7 +540,6 @@ struct gigaset_driver {
         unsigned minor;
         unsigned minors;
         struct cardstate *cs;
-        unsigned *flags;
         int blocked;
 
         const struct gigaset_ops *ops;
@@ -767,10 +767,6 @@ void gigaset_freedriver(struct gigaset_driver *drv);
 void gigaset_debugdrivers(void);
 struct cardstate *gigaset_get_cs_by_tty(struct tty_struct *tty);
 struct cardstate *gigaset_get_cs_by_id(int id);
-
-/* For drivers without fixed assignment device<->cardstate (usb) */
-struct cardstate *gigaset_getunassignedcs(struct gigaset_driver *drv);
-void gigaset_unassign(struct cardstate *cs);
 void gigaset_blockdriver(struct gigaset_driver *drv);
 
 /* Allocate and initialize card state. Calls hardware dependent
@@ -789,7 +785,7 @@ int gigaset_start(struct cardstate *cs);
 void gigaset_stop(struct cardstate *cs);
 
 /* Tell common.c that the driver is being unloaded. */
-void gigaset_shutdown(struct cardstate *cs);
+int gigaset_shutdown(struct cardstate *cs);
 
 /* Tell common.c that an skb has been sent. */
 void gigaset_skb_sent(struct bc_state *bcs, struct sk_buff *skb);
diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
index f4731c9984f6..af195b07c191 100644
--- a/drivers/isdn/gigaset/interface.c
+++ b/drivers/isdn/gigaset/interface.c
@@ -161,7 +161,7 @@ static int if_open(struct tty_struct *tty, struct file *filp)
         tty->driver_data = NULL;
 
         cs = gigaset_get_cs_by_tty(tty);
-        if (!cs)
+        if (!cs || !try_module_get(cs->driver->owner))
                 return -ENODEV;
 
         if (mutex_lock_interruptible(&cs->mutex))
@@ -207,6 +207,8 @@ static void if_close(struct tty_struct *tty, struct file *filp)
         }
 
         mutex_unlock(&cs->mutex);
+
+        module_put(cs->driver->owner);
 }
 
 static int if_ioctl(struct tty_struct *tty, struct file *file,
diff --git a/drivers/isdn/gigaset/usb-gigaset.c b/drivers/isdn/gigaset/usb-gigaset.c
index c58ddee68dea..77d20ab0cd4d 100644
--- a/drivers/isdn/gigaset/usb-gigaset.c
+++ b/drivers/isdn/gigaset/usb-gigaset.c
@@ -115,7 +115,6 @@ static int gigaset_resume(struct usb_interface *intf);
 static int gigaset_pre_reset(struct usb_interface *intf);
 
 static struct gigaset_driver *driver = NULL;
-static struct cardstate *cardstate = NULL;
 
 /* usb specific object needed to register this driver with the usb subsystem */
 static struct usb_driver gigaset_usb_driver = {
@@ -727,11 +726,10 @@ static int gigaset_probe(struct usb_interface *interface,
 
         dev_info(&udev->dev, "%s: Device matched ... !\n", __func__);
 
-        cs = gigaset_getunassignedcs(driver);
-        if (!cs) {
-                dev_warn(&udev->dev, "no free cardstate\n");
+        /* allocate memory for our device state and intialize it */
+        cs = gigaset_initcs(driver, 1, 1, 0, cidmode, GIGASET_MODULENAME);
+        if (!cs)
                 return -ENODEV;
-        }
         ucs = cs->hw.usb;
 
         /* save off device structure ptrs for later use */
@@ -818,7 +816,7 @@ error:
         usb_put_dev(ucs->udev);
         ucs->udev = NULL;
         ucs->interface = NULL;
-        gigaset_unassign(cs);
+        gigaset_freecs(cs);
         return retval;
 }
 
@@ -852,7 +850,7 @@ static void gigaset_disconnect(struct usb_interface *interface)
         ucs->interface = NULL;
         ucs->udev = NULL;
         cs->dev = NULL;
-        gigaset_unassign(cs);
+        gigaset_freecs(cs);
 }
 
 /* gigaset_suspend
@@ -934,11 +932,6 @@ static int __init usb_gigaset_init(void)
                                        &ops, THIS_MODULE)) == NULL)
                 goto error;
 
-        /* allocate memory for our device state and intialize it */
-        cardstate = gigaset_initcs(driver, 1, 1, 0, cidmode, GIGASET_MODULENAME);
-        if (!cardstate)
-                goto error;
-
         /* register this driver with the USB subsystem */
         result = usb_register(&gigaset_usb_driver);
         if (result < 0) {
@@ -951,9 +944,7 @@ static int __init usb_gigaset_init(void)
         info(DRIVER_DESC);
         return 0;
 
-error:  if (cardstate)
-                gigaset_freecs(cardstate);
-        cardstate = NULL;
+error:
         if (driver)
                 gigaset_freedriver(driver);
         driver = NULL;
@@ -967,11 +958,16 @@ error:	if (cardstate)
  */
 static void __exit usb_gigaset_exit(void)
 {
+        int i;
+
         gigaset_blockdriver(driver); /* => probe will fail
                                       * => no gigaset_start any more
                                       */
 
-        gigaset_shutdown(cardstate);
+        /* stop all connected devices */
+        for (i = 0; i < driver->minors; i++)
+                gigaset_shutdown(driver->cs + i);
+
         /* from now on, no isdn callback should be possible */
 
         /* deregister this driver with the USB subsystem */
@@ -979,8 +975,6 @@ static void __exit usb_gigaset_exit(void)
         /* this will call the disconnect-callback */
         /* from now on, no disconnect/probe callback should be running */
 
-        gigaset_freecs(cardstate);
-        cardstate = NULL;
         gigaset_freedriver(driver);
         driver = NULL;
 }