Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

1 files changed, 15 insertions, 3 deletions

diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
index 02d1b632711..015f92aab44 100644
--- a/drivers/media/v4l2-core/v4l2-device.c
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -158,7 +158,17 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 	/* Warn if we apparently re-register a subdev */
 	WARN_ON(sd->v4l2_dev != NULL);
 
-	if (!try_module_get(sd->owner))
+	/*
+	 * The reason to acquire the module here is to avoid unloading
+	 * a module of sub-device which is registered to a media
+	 * device. To make it possible to unload modules for media
+	 * devices that also register sub-devices, do not
+	 * try_module_get() such sub-device owners.
+	 */
+	sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
+		sd->owner == v4l2_dev->dev->driver->owner;
+
+	if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
 		return -ENODEV;
 
 	sd->v4l2_dev = v4l2_dev;
@@ -192,7 +202,8 @@ error_unregister:
 	if (sd->internal_ops && sd->internal_ops->unregistered)
 		sd->internal_ops->unregistered(sd);
 error_module:
-	module_put(sd->owner);
+	if (!sd->owner_v4l2_dev)
+		module_put(sd->owner);
 	sd->v4l2_dev = NULL;
 	return err;
 }
@@ -280,6 +291,7 @@ void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 	}
 #endif
 	video_unregister_device(sd->devnode);
-	module_put(sd->owner);
+	if (!sd->owner_v4l2_dev)
+		module_put(sd->owner);
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);