char: make misc_deregister a void function

With well over 200+ users of this api, there are a mere 12 users that
actually checked the return value of this function.  And all of them
really didn't do anything with that information as the system or module
was shutting down no matter what.

So stop pretending like it matters, and just return void from
misc_deregister().  If something goes wrong in the call, you will get a
WARNING splat in the syslog so you know how to fix up your driver.
Other than that, there's nothing that can go wrong.

Cc: Alasdair Kergon <agk@redhat.com>
Cc: Neil Brown <neilb@suse.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Christine Caulfield <ccaulfie@redhat.com>
Cc: David Teigland <teigland@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Acked-by: Joel Becker <jlbec@evilplan.org>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

16 files changed, 27 insertions, 59 deletions

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index c83ef9652bc9..8069b361b8dd 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -243,17 +243,15 @@ int misc_register(struct miscdevice * misc)
  *      @misc: device to unregister
  *
  *      Unregister a miscellaneous device that was previously
- *      successfully registered with misc_register(). Success
- *      is indicated by a zero return, a negative errno code
- *      indicates an error.
+ *      successfully registered with misc_register().
  */
 
-int misc_deregister(struct miscdevice *misc)
+void misc_deregister(struct miscdevice *misc)
 {
         int i = DYNAMIC_MINORS - misc->minor - 1;
 
         if (WARN_ON(list_empty(&misc->list)))
-                return -EINVAL;
+                return;
 
         mutex_lock(&misc_mtx);
         list_del(&misc->list);
@@ -261,7 +259,6 @@ int misc_deregister(struct miscdevice *misc)
         if (i < DYNAMIC_MINORS && i >= 0)
                 clear_bit(i, misc_minors);
         mutex_unlock(&misc_mtx);
-        return 0;
 }
 
 EXPORT_SYMBOL(misc_register);
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 720ceeb7fa9b..80a439543259 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1919,9 +1919,7 @@ int __init dm_interface_init(void)
 
 void dm_interface_exit(void)
 {
-        if (misc_deregister(&_dm_misc) < 0)
-                DMERR("misc_deregister failed for control device");
-
+        misc_deregister(&_dm_misc);
         dm_hash_exit();
 }
 
diff --git a/drivers/misc/vmw_vmci/vmci_host.c b/drivers/misc/vmw_vmci/vmci_host.c
index a721b5d8a9da..9ec262a52656 100644
--- a/drivers/misc/vmw_vmci/vmci_host.c
+++ b/drivers/misc/vmw_vmci/vmci_host.c
@@ -1031,14 +1031,9 @@ int __init vmci_host_init(void)
 
 void __exit vmci_host_exit(void)
 {
-        int error;
-
         vmci_host_device_initialized = false;
 
-        error = misc_deregister(&vmci_host_miscdev);
-        if (error)
-                pr_warn("Error unregistering character device: %d\n", error);
-
+        misc_deregister(&vmci_host_miscdev);
         vmci_ctx_destroy(host_context);
         vmci_qp_broker_exit();
 
diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c
index 167783fa7ac1..72c933375233 100644
--- a/drivers/rtc/rtc-ds1374.c
+++ b/drivers/rtc/rtc-ds1374.c
@@ -666,9 +666,8 @@ static int ds1374_remove(struct i2c_client *client)
 #ifdef CONFIG_RTC_DRV_DS1374_WDT
         int res;
 
-        res = misc_deregister(&ds1374_miscdev);
-        if (!res)
-                ds1374_miscdev.parent = NULL;
+        misc_deregister(&ds1374_miscdev);
+        ds1374_miscdev.parent = NULL;
         unregister_reboot_notifier(&ds1374_wdt_notifier);
 #endif
 
diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index c5c037ccf32c..2c75d90b26c8 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -863,14 +863,9 @@ static int __init ashmem_init(void)
 
 static void __exit ashmem_exit(void)
 {
-        int ret;
-
         unregister_shrinker(&ashmem_shrinker);
 
-        ret = misc_deregister(&ashmem_misc);
-        if (unlikely(ret))
-                pr_err("failed to unregister misc device!\n");
-
+        misc_deregister(&ashmem_misc);
         kmem_cache_destroy(ashmem_range_cachep);
         kmem_cache_destroy(ashmem_area_cachep);
 
diff --git a/drivers/staging/android/ion/ion_test.c b/drivers/staging/android/ion/ion_test.c
index 7d6e6b6bc894..b8dcf5a26cc4 100644
--- a/drivers/staging/android/ion/ion_test.c
+++ b/drivers/staging/android/ion/ion_test.c
@@ -269,7 +269,8 @@ static int ion_test_remove(struct platform_device *pdev)
         if (!testdev)
                 return -ENODATA;
 
-        return misc_deregister(&testdev->misc);
+        misc_deregister(&testdev->misc);
+        return 0;
 }
 
 static struct platform_device *ion_test_pdev;
diff --git a/drivers/staging/lustre/lustre/libcfs/module.c b/drivers/staging/lustre/lustre/libcfs/module.c
index e60b2e9b9194..e7074006e41b 100644
--- a/drivers/staging/lustre/lustre/libcfs/module.c
+++ b/drivers/staging/lustre/lustre/libcfs/module.c
@@ -467,9 +467,7 @@ static void exit_libcfs_module(void)
         cfs_crypto_unregister();
         cfs_wi_shutdown();
 
-        rc = misc_deregister(&libcfs_dev);
-        if (rc)
-                CERROR("misc_deregister error %d\n", rc);
+        misc_deregister(&libcfs_dev);
 
         cfs_cpu_fini();
 
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index dfcc02c93648..f114a9dbb48f 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1573,9 +1573,9 @@ static int __init vhost_scsi_register(void)
         return misc_register(&vhost_scsi_misc);
 }
 
-static int vhost_scsi_deregister(void)
+static void vhost_scsi_deregister(void)
 {
-        return misc_deregister(&vhost_scsi_misc);
+        misc_deregister(&vhost_scsi_misc);
 }
 
 static char *vhost_scsi_dump_proto_id(struct vhost_scsi_tport *tport)
diff --git a/drivers/watchdog/at91rm9200_wdt.c b/drivers/watchdog/at91rm9200_wdt.c
index 41cecb55766c..9ba1153465ae 100644
--- a/drivers/watchdog/at91rm9200_wdt.c
+++ b/drivers/watchdog/at91rm9200_wdt.c
@@ -269,9 +269,8 @@ static int at91wdt_remove(struct platform_device *pdev)
         if (res)
                 dev_warn(dev, "failed to unregister restart handler\n");
 
-        res = misc_deregister(&at91wdt_miscdev);
-        if (!res)
-                at91wdt_miscdev.parent = NULL;
+        misc_deregister(&at91wdt_miscdev);
+        at91wdt_miscdev.parent = NULL;
 
         return res;
 }
diff --git a/drivers/watchdog/ks8695_wdt.c b/drivers/watchdog/ks8695_wdt.c
index b7ea39b455c8..1e41818a44bc 100644
--- a/drivers/watchdog/ks8695_wdt.c
+++ b/drivers/watchdog/ks8695_wdt.c
@@ -254,13 +254,10 @@ static int ks8695wdt_probe(struct platform_device *pdev)
 
 static int ks8695wdt_remove(struct platform_device *pdev)
 {
-        int res;
-
-        res = misc_deregister(&ks8695wdt_miscdev);
-        if (!res)
-                ks8695wdt_miscdev.parent = NULL;
+        misc_deregister(&ks8695wdt_miscdev);
+        ks8695wdt_miscdev.parent = NULL;
 
-        return res;
+        return 0;
 }
 
 static void ks8695wdt_shutdown(struct platform_device *pdev)
diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
index 119beb7f6017..4b541934b6c5 100644
--- a/drivers/watchdog/ts72xx_wdt.c
+++ b/drivers/watchdog/ts72xx_wdt.c
@@ -428,7 +428,8 @@ static int ts72xx_wdt_probe(struct platform_device *pdev)
 
 static int ts72xx_wdt_remove(struct platform_device *pdev)
 {
-        return misc_deregister(&ts72xx_wdt_miscdev);
+        misc_deregister(&ts72xx_wdt_miscdev);
+        return 0;
 }
 
 static struct platform_driver ts72xx_wdt_driver = {
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index cd7ef34d2dce..6bad63379a4c 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2163,8 +2163,7 @@ static int btrfs_interface_init(void)
 
 static void btrfs_interface_exit(void)
 {
-        if (misc_deregister(&btrfs_misc) < 0)
-                printk(KERN_INFO "BTRFS: misc_deregister failed for control device\n");
+        misc_deregister(&btrfs_misc);
 }
 
 static void btrfs_print_info(void)
diff --git a/fs/dlm/plock.c b/fs/dlm/plock.c
index e0ab3a93eeff..5532f097f6da 100644
--- a/fs/dlm/plock.c
+++ b/fs/dlm/plock.c
@@ -509,7 +509,6 @@ int dlm_plock_init(void)
 
 void dlm_plock_exit(void)
 {
-        if (misc_deregister(&plock_dev_misc) < 0)
-                log_print("dlm_plock_exit: misc_deregister failed");
+        misc_deregister(&plock_dev_misc);
 }
 
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index fb85f32e9eca..75ecc0d3bc85 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -362,18 +362,15 @@ fail:
 
 int dlm_device_deregister(struct dlm_ls *ls)
 {
-        int error;
-
         /* The device is not registered.  This happens when the lockspace
            was never used from userspace, or when device_create_lockspace()
            calls dlm_release_lockspace() after the register fails. */
         if (!ls->ls_device.name)
                 return 0;
 
-        error = misc_deregister(&ls->ls_device);
-        if (!error)
-                kfree(ls->ls_device.name);
-        return error;
+        misc_deregister(&ls->ls_device);
+        kfree(ls->ls_device.name);
+        return 0;
 }
 
 static int device_user_purge(struct dlm_user_proc *proc,
diff --git a/fs/ocfs2/stack_user.c b/fs/ocfs2/stack_user.c
index 2768eb1da2b8..ced70c8139f7 100644
--- a/fs/ocfs2/stack_user.c
+++ b/fs/ocfs2/stack_user.c
@@ -655,14 +655,7 @@ static int ocfs2_control_init(void)
 
 static void ocfs2_control_exit(void)
 {
-        int rc;
-
-        rc = misc_deregister(&ocfs2_control_device);
-        if (rc)
-                printk(KERN_ERR
-                       "ocfs2: Unable to deregister ocfs2_control device "
-                       "(errno %d)\n",
-                       -rc);
+        misc_deregister(&ocfs2_control_device);
 }
 
 static void fsdlm_lock_ast_wrapper(void *astarg)
diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
index 819077c32690..81f6e427ba6b 100644
--- a/include/linux/miscdevice.h
+++ b/include/linux/miscdevice.h
@@ -67,7 +67,7 @@ struct miscdevice  {
 };
 
 extern int misc_register(struct miscdevice *misc);
-extern int misc_deregister(struct miscdevice *misc);
+extern void misc_deregister(struct miscdevice *misc);
 
 #define MODULE_ALIAS_MISCDEV(minor)                             \
         MODULE_ALIAS("char-major-" __stringify(MISC_MAJOR)      \