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);