Re: [PATCH 22/59] Staging: hv: vmbus: Get rid of the unused name field in struct hv_driver

[Greg KH <greg@kroah.com>]

On Thu, Aug 25, 2011 at 02:28:20PM -0700, Greg KH wrote:
> > Man, if you want something done right, you have to do it yourself, let
> > me go make these changes so you don't have to do any new work at this
> > point in time, hopefully your other patches will apply...
> 
> What, vmbus_child_driver_register() takes a struct driver *?
> 
> No wonder things are so messed up here, and why you got confused.  Let
> me pound on this for a bit to see if I can get it cleaned up to be more
> "sane"...

Ok, here's what I'm talking about.  It properly hooks up the module
reference counting issues that you had yet to take care of as well (see,
you got that for free just by getting the logic correct, and the code is
even smaller than before overall, it's a win-win all around...)

The patch below works for me, I've committed it and will work out how to
apply the rest of your patch series now.

-----------------

From: Greg Kroah-Hartman <gregkh@suse.de>
Date: Thu, 25 Aug 2011 15:07:32 -0700
Subject: Staging: hv: fix up driver registering mess

Individual drivers should never be touching the 'struct device' field,
so if that is a requirement to pass to the vmbus core, you know
something is wrong.

This patch fixes that all up, and resolves the problem where the module
reference counting was not happening properly for the individual drivers
as well.  Overall, it reduces the lines of code the individual drivers
have to have, which tells you that this is the correct thing to do.

Also, somehow the _GPL marking for the functions got removed on an older
patch.  As the name of the function was changing, properly change the
_GPL marking as well at the same time.

Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/staging/hv/blkvsc_drv.c  |   17 ++------------
 drivers/staging/hv/hv_mouse.c    |   21 ++---------------
 drivers/staging/hv/hv_util.c     |    9 ++-----
 drivers/staging/hv/hyperv.h      |    8 +++++-
 drivers/staging/hv/hyperv_net.h  |    1 -
 drivers/staging/hv/netvsc.c      |   14 ------------
 drivers/staging/hv/netvsc_drv.c  |   19 ++--------------
 drivers/staging/hv/storvsc_drv.c |   24 ++++++---------------
 drivers/staging/hv/vmbus_drv.c   |   43 ++++++++++++++++++-------------------
 9 files changed, 46 insertions(+), 110 deletions(-)

diff --git a/drivers/staging/hv/blkvsc_drv.c b/drivers/staging/hv/blkvsc_drv.c
index d170f24..07dc9ed 100644
--- a/drivers/staging/hv/blkvsc_drv.c
+++ b/drivers/staging/hv/blkvsc_drv.c
@@ -109,7 +109,6 @@ struct block_device_context {
 	int users;
 };
 
-static const char *drv_name = "blkvsc";
 
 /*
  * There is a circular dependency involving blkvsc_request_completion()
@@ -805,6 +804,7 @@ MODULE_DEVICE_TABLE(vmbus, id_table);
 
 /* The one and only one */
 static  struct hv_driver blkvsc_drv = {
+	.name = "blkvsc",
 	.id_table = id_table,
 	.probe =  blkvsc_probe,
 	.remove =  blkvsc_remove,
@@ -824,24 +824,13 @@ static const struct block_device_operations block_ops = {
  */
 static int blkvsc_drv_init(void)
 {
-	struct hv_driver *drv = &blkvsc_drv;
-	int ret;
-
 	BUILD_BUG_ON(sizeof(sector_t) != 8);
-
-	drv->driver.name = drv_name;
-
-	/* The driver belongs to vmbus */
-	ret = vmbus_child_driver_register(&drv->driver);
-
-	return ret;
+	return vmbus_driver_register(&blkvsc_drv);
 }
 
-
 static void blkvsc_drv_exit(void)
 {
-
-	vmbus_child_driver_unregister(&blkvsc_drv.driver);
+	vmbus_driver_unregister(&blkvsc_drv);
 }
 
 /*
diff --git a/drivers/staging/hv/hv_mouse.c b/drivers/staging/hv/hv_mouse.c
index ebd1715..5727173 100644
--- a/drivers/staging/hv/hv_mouse.c
+++ b/drivers/staging/hv/hv_mouse.c
@@ -176,8 +176,6 @@ struct mousevsc_dev {
 };
 
 
-static const char *driver_name = "mousevsc";
-
 static void deviceinfo_callback(struct hv_device *dev, struct hv_input_dev_info *info);
 static void inputreport_callback(struct hv_device *dev, void *packet, u32 len);
 static void reportdesc_callback(struct hv_device *dev, void *packet, u32 len);
@@ -921,33 +919,20 @@ static const struct hv_vmbus_device_id id_table[] = {
 /* MODULE_DEVICE_TABLE(vmbus, id_table); */
 
 static struct  hv_driver mousevsc_drv = {
+	.name = "mousevsc",
 	.id_table = id_table,
 	.probe = mousevsc_probe,
 	.remove = mousevsc_remove,
 };
 
-static void mousevsc_drv_exit(void)
-{
-	vmbus_child_driver_unregister(&mousevsc_drv.driver);
-}
-
 static int __init mousevsc_init(void)
 {
-	struct hv_driver *drv = &mousevsc_drv;
-
-	DPRINT_INFO(INPUTVSC_DRV, "Hyper-V Mouse driver initializing.");
-
-	drv->driver.name = driver_name;
-
-	/* The driver belongs to vmbus */
-	vmbus_child_driver_register(&drv->driver);
-
-	return 0;
+	return vmbus_driver_register(&mousevsc_drv);
 }
 
 static void __exit mousevsc_exit(void)
 {
-	mousevsc_drv_exit();
+	vmbus_driver_unregister(&mousevsc_drv);
 }
 
 /*
diff --git a/drivers/staging/hv/hv_util.c b/drivers/staging/hv/hv_util.c
index b0d89de..f2f456f 100644
--- a/drivers/staging/hv/hv_util.c
+++ b/drivers/staging/hv/hv_util.c
@@ -34,8 +34,6 @@ static u8 *shut_txf_buf;
 static u8 *time_txf_buf;
 static u8 *hbeat_txf_buf;
 
-static const char *driver_name = "hv_util";
-
 static void shutdown_onchannelcallback(void *context)
 {
 	struct vmbus_channel *channel = context;
@@ -244,6 +242,7 @@ MODULE_DEVICE_TABLE(vmbus, id_table);
 
 /* The one and only one */
 static  struct hv_driver util_drv = {
+	.name = "hv_util",
 	.id_table = id_table,
 	.probe =  util_probe,
 	.remove =  util_remove,
@@ -277,9 +276,7 @@ static int __init init_hyperv_utils(void)
 
 	hv_cb_utils[HV_KVP_MSG].callback = &hv_kvp_onchannelcallback;
 
-	util_drv.driver.name = driver_name;
-
-	return vmbus_child_driver_register(&util_drv.driver);
+	return vmbus_driver_register(&util_drv);
 }
 
 static void exit_hyperv_utils(void)
@@ -311,7 +308,7 @@ static void exit_hyperv_utils(void)
 	kfree(shut_txf_buf);
 	kfree(time_txf_buf);
 	kfree(hbeat_txf_buf);
-	vmbus_child_driver_unregister(&util_drv.driver);
+	vmbus_driver_unregister(&util_drv);
 }
 
 module_init(init_hyperv_utils);
diff --git a/drivers/staging/hv/hyperv.h b/drivers/staging/hv/hyperv.h
index d96de66..c249811 100644
--- a/drivers/staging/hv/hyperv.h
+++ b/drivers/staging/hv/hyperv.h
@@ -845,8 +845,12 @@ static inline struct hv_driver *drv_to_hv_drv(struct device_driver *d)
 
 
 /* Vmbus interface */
-int vmbus_child_driver_register(struct device_driver *drv);
-void vmbus_child_driver_unregister(struct device_driver *drv);
+#define vmbus_driver_register(driver)	\
+	__vmbus_driver_register(driver, THIS_MODULE, KBUILD_MODNAME)
+int __must_check __vmbus_driver_register(struct hv_driver *hv_driver,
+					 struct module *owner,
+					 const char *mod_name);
+void vmbus_driver_unregister(struct hv_driver *hv_driver);
 
 /**
  * VMBUS_DEVICE - macro used to describe a specific hyperv vmbus device
diff --git a/drivers/staging/hv/hyperv_net.h b/drivers/staging/hv/hyperv_net.h
index 27f987b..5782fea 100644
--- a/drivers/staging/hv/hyperv_net.h
+++ b/drivers/staging/hv/hyperv_net.h
@@ -96,7 +96,6 @@ void netvsc_linkstatus_callback(struct hv_device *device_obj,
 				unsigned int status);
 int netvsc_recv_callback(struct hv_device *device_obj,
 			struct hv_netvsc_packet *packet);
-int netvsc_initialize(struct hv_driver *drv);
 int rndis_filter_open(struct hv_device *dev);
 int rndis_filter_close(struct hv_device *dev);
 int rndis_filter_device_add(struct hv_device *dev,
diff --git a/drivers/staging/hv/netvsc.c b/drivers/staging/hv/netvsc.c
index 6f4541b..cb02eed 100644
--- a/drivers/staging/hv/netvsc.c
+++ b/drivers/staging/hv/netvsc.c
@@ -32,9 +32,6 @@
 #include "hyperv_net.h"
 
 
-/* Globals */
-static const char *driver_name = "netvsc";
-
 static struct netvsc_device *alloc_net_device(struct hv_device *device)
 {
 	struct netvsc_device *net_device;
@@ -992,14 +989,3 @@ cleanup:
 
 	return ret;
 }
-
-/*
- * netvsc_initialize - Main entry point
- */
-int netvsc_initialize(struct hv_driver *drv)
-{
-
-	drv->name = driver_name;
-
-	return 0;
-}
diff --git a/drivers/staging/hv/netvsc_drv.c b/drivers/staging/hv/netvsc_drv.c
index 2d2955c..ad1ef03 100644
--- a/drivers/staging/hv/netvsc_drv.c
+++ b/drivers/staging/hv/netvsc_drv.c
@@ -422,6 +422,7 @@ MODULE_DEVICE_TABLE(vmbus, id_table);
 
 /* The one and only one */
 static struct  hv_driver netvsc_drv = {
+	.name = "netvsc",
 	.id_table = id_table,
 	.probe = netvsc_probe,
 	.remove = netvsc_remove,
@@ -429,26 +430,12 @@ static struct  hv_driver netvsc_drv = {
 
 static void __exit netvsc_drv_exit(void)
 {
-	vmbus_child_driver_unregister(&netvsc_drv.driver);
+	vmbus_driver_unregister(&netvsc_drv);
 }
 
-
 static int __init netvsc_drv_init(void)
 {
-	struct hv_driver *drv = &netvsc_drv;
-	int ret;
-
-	pr_info("initializing....");
-
-	/* Callback to client driver to complete the initialization */
-	netvsc_initialize(drv);
-
-	drv->driver.name = drv->name;
-
-	/* The driver belongs to vmbus */
-	ret = vmbus_child_driver_register(&drv->driver);
-
-	return ret;
+	return vmbus_driver_register(&netvsc_drv);
 }
 
 MODULE_LICENSE("GPL");
diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index 6f67e9b..0297418 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -41,8 +41,6 @@ static int storvsc_ringbuffer_size = STORVSC_RING_BUFFER_SIZE;
 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
 
-static const char *driver_name = "storvsc";
-
 struct hv_host_device {
 	struct hv_device *dev;
 	struct kmem_cache *request_pool;
@@ -718,6 +716,7 @@ static int storvsc_probe(struct hv_device *device)
 /* The one and only one */
 
 static struct hv_driver storvsc_drv = {
+	.name = "storvsc",
 	.id_table = id_table,
 	.probe = storvsc_probe,
 	.remove = storvsc_remove,
@@ -725,8 +724,6 @@ static struct hv_driver storvsc_drv = {
 
 static int __init storvsc_drv_init(void)
 {
-	int ret;
-	struct hv_driver *drv = &storvsc_drv;
 	u32 max_outstanding_req_per_channel;
 
 	/*
@@ -735,29 +732,22 @@ static int __init storvsc_drv_init(void)
 	 * the ring buffer indices) by the max request size (which is
 	 * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
 	 */
-
 	max_outstanding_req_per_channel =
-	((storvsc_ringbuffer_size - PAGE_SIZE) /
-	ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
-	sizeof(struct vstor_packet) + sizeof(u64),
-	sizeof(u64)));
+		((storvsc_ringbuffer_size - PAGE_SIZE) /
+		ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
+		sizeof(struct vstor_packet) + sizeof(u64),
+		sizeof(u64)));
 
 	if (max_outstanding_req_per_channel <
 	    STORVSC_MAX_IO_REQUESTS)
 		return -1;
 
-	drv->driver.name = driver_name;
-
-
-	/* The driver belongs to vmbus */
-	ret = vmbus_child_driver_register(&drv->driver);
-
-	return ret;
+	return vmbus_driver_register(&storvsc_drv);
 }
 
 static void __exit storvsc_drv_exit(void)
 {
-	vmbus_child_driver_unregister(&storvsc_drv.driver);
+	vmbus_driver_unregister(&storvsc_drv);
 }
 
 MODULE_LICENSE("GPL");
diff --git a/drivers/staging/hv/vmbus_drv.c b/drivers/staging/hv/vmbus_drv.c
index 0114b04..26f4901 100644
--- a/drivers/staging/hv/vmbus_drv.c
+++ b/drivers/staging/hv/vmbus_drv.c
@@ -552,51 +552,50 @@ static int vmbus_bus_init(int irq)
 }
 
 /**
- * vmbus_child_driver_register() - Register a vmbus's child driver
- * @drv:        Pointer to driver structure you want to register
- *
+ * __vmbus_child_driver_register - Register a vmbus's driver
+ * @drv: Pointer to driver structure you want to register
+ * @owner: owner module of the drv
+ * @mod_name: module name string
  *
  * Registers the given driver with Linux through the 'driver_register()' call
- * And sets up the hyper-v vmbus handling for this driver.
+ * and sets up the hyper-v vmbus handling for this driver.
  * It will return the state of the 'driver_register()' call.
  *
- * Mainly used by Hyper-V drivers.
  */
-int vmbus_child_driver_register(struct device_driver *drv)
+int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
 {
 	int ret;
 
-	pr_info("child driver registering - name %s\n", drv->name);
+	pr_info("registering driver %s\n", hv_driver->name);
 
-	/* The child driver on this vmbus */
-	drv->bus = &hv_bus;
+	hv_driver->driver.name = hv_driver->name;
+	hv_driver->driver.owner = owner;
+	hv_driver->driver.mod_name = mod_name;
+	hv_driver->driver.bus = &hv_bus;
 
-	ret = driver_register(drv);
+	ret = driver_register(&hv_driver->driver);
 
 	vmbus_request_offers();
 
 	return ret;
 }
-EXPORT_SYMBOL(vmbus_child_driver_register);
+EXPORT_SYMBOL_GPL(__vmbus_driver_register);
 
 /**
- * vmbus_child_driver_unregister() - Unregister a vmbus's child driver
- * @drv:        Pointer to driver structure you want to un-register
- *
- *
- * Un-register the given driver with Linux through the 'driver_unregister()'
- * call. And ungegisters the driver from the Hyper-V vmbus handler.
+ * vmbus_driver_unregister() - Unregister a vmbus's driver
+ * @drv: Pointer to driver structure you want to un-register
  *
- * Mainly used by Hyper-V drivers.
+ * Un-register the given driver that was previous registered with a call to
+ * vmbus_driver_register()
  */
-void vmbus_child_driver_unregister(struct device_driver *drv)
+void vmbus_driver_unregister(struct hv_driver *hv_driver)
 {
-	pr_info("child driver unregistering - name %s\n", drv->name);
+	pr_info("unregistering driver %s\n", hv_driver->name);
 
-	driver_unregister(drv);
+	driver_unregister(&hv_driver->driver);
 
 }
-EXPORT_SYMBOL(vmbus_child_driver_unregister);
+EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
 
 /*
  * vmbus_child_device_create - Creates and registers a new child device
-- 
1.7.6