[PATCH] pnp: PNP: adjust pnp_register_driver signature

Remove the assumption that pnp_register_driver() returns the number of devices claimed. Returning the count is unreliable because devices may be hot-plugged in the future. This changes the convention to "zero for success, or a negative error value," which matches pci_register_driver(), acpi_bus_register_driver(), and platform_driver_register(). Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Adam Belay <ambx1@neo.rr.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] pnp: PNP: adjust pnp_register_driver signature
Remove the assumption that pnp_register_driver() returns the number of devices claimed. Returning the count is unreliable because devices may be hot-plugged in the future. This changes the convention to "zero for success, or a negative error value," which matches pci_register_driver(), acpi_bus_register_driver(), and platform_driver_register(). Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Adam Belay <ambx1@neo.rr.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Bjorn Helgaas · Linus Torvalds
1 parent 070c699983
Showing 3 changed files with 11 additions and 27 deletions Side-by-side Diff
Documentation/pnp.txt
drivers/pnp/card.c
drivers/pnp/driver.c
@@ -115,6 +115,9 @@
 pnp_register_driver
 - adds a PnP driver to the Plug and Play Layer
 - this includes driver model integration
+- returns zero for success or a negative error number for failure; count
+  calls to the .add() method if you need to know how many devices bind to
+  the driver
  
 pnp_unregister_driver
 - removes a PnP driver from the Plug and Play Layer
@@ -47,7 +47,7 @@
 {
 	dev->card_link = NULL;
 }
- 
+
 static void card_remove_first(struct pnp_dev * dev)
 {
 	struct pnp_card_driver * drv = to_pnp_card_driver(dev->driver);
@@ -361,7 +361,7 @@
  
 int pnp_register_card_driver(struct pnp_card_driver * drv)
 {
-	int count;
+	int error;
 	struct list_head *pos, *temp;
  
 	drv->link.name = drv->name;
  
  
  
@@ -372,21 +372,19 @@
 	drv->link.suspend = drv->suspend ? card_suspend : NULL;
 	drv->link.resume = drv->resume ? card_resume : NULL;
  
-	count = pnp_register_driver(&drv->link);
-	if (count < 0)
-		return count;
+	error = pnp_register_driver(&drv->link);
+	if (error < 0)
+		return error;
  
 	spin_lock(&pnp_lock);
 	list_add_tail(&drv->global_list, &pnp_card_drivers);
 	spin_unlock(&pnp_lock);
  
-	count = 0;
-
 	list_for_each_safe(pos,temp,&pnp_cards){
 		struct pnp_card *card = list_entry(pos, struct pnp_card, global_list);
-		count += card_probe(card,drv);
+		card_probe(card,drv);
 	}
-	return count;
+	return 0;
 }
  
 /**
@@ -201,31 +201,14 @@
 	.resume = pnp_bus_resume,
 };
  
-
-static int count_devices(struct device * dev, void * c)
-{
-	int * count = c;
-	(*count)++;
-	return 0;
-}
-
 int pnp_register_driver(struct pnp_driver *drv)
 {
-	int count;
-
 	pnp_dbg("the driver '%s' has been registered", drv->name);
  
 	drv->driver.name = drv->name;
 	drv->driver.bus = &pnp_bus_type;
  
-	count = driver_register(&drv->driver);
-
-	/* get the number of initial matches */
-	if (count >= 0){
-		count = 0;
-		driver_for_each_device(&drv->driver, NULL, &count, count_devices);
-	}
-	return count;
+	return driver_register(&drv->driver);
 }
  
 void pnp_unregister_driver(struct pnp_driver *drv)
...	...	@@ -115,6 +115,9 @@
115	115	pnp_register_driver
116	116	- adds a PnP driver to the Plug and Play Layer
117	117	- this includes driver model integration
	118	+- returns zero for success or a negative error number for failure; count
	119	+ calls to the .add() method if you need to know how many devices bind to
	120	+ the driver
118	121
119	122	pnp_unregister_driver
120	123	- removes a PnP driver from the Plug and Play Layer
...	...	@@ -47,7 +47,7 @@
47	47	{
48	48	dev->card_link = NULL;
49	49	}
50		-
	50	+
51	51	static void card_remove_first(struct pnp_dev * dev)
52	52	{
53	53	struct pnp_card_driver * drv = to_pnp_card_driver(dev->driver);
...	...	@@ -361,7 +361,7 @@
361	361
362	362	int pnp_register_card_driver(struct pnp_card_driver * drv)
363	363	{
364		- int count;
	364	+ int error;
365	365	struct list_head pos, temp;
366	366
367	367	drv->link.name = drv->name;
368	368
369	369
370	370
...	...	@@ -372,21 +372,19 @@
372	372	drv->link.suspend = drv->suspend ? card_suspend : NULL;
373	373	drv->link.resume = drv->resume ? card_resume : NULL;
374	374
375		- count = pnp_register_driver(&drv->link);
376		- if (count < 0)
377		- return count;
	375	+ error = pnp_register_driver(&drv->link);
	376	+ if (error < 0)
	377	+ return error;
378	378
379	379	spin_lock(&pnp_lock);
380	380	list_add_tail(&drv->global_list, &pnp_card_drivers);
381	381	spin_unlock(&pnp_lock);
382	382
383		- count = 0;
384		-
385	383	list_for_each_safe(pos,temp,&pnp_cards){
386	384	struct pnp_card *card = list_entry(pos, struct pnp_card, global_list);
387		- count += card_probe(card,drv);
	385	+ card_probe(card,drv);
388	386	}
389		- return count;
	387	+ return 0;
390	388	}
391	389
392	390	/**
...	...	@@ -201,31 +201,14 @@
201	201	.resume = pnp_bus_resume,
202	202	};
203	203
204		-
205		-static int count_devices(struct device * dev, void * c)
206		-{
207		- int * count = c;
208		- (*count)++;
209		- return 0;
210		-}
211		-
212	204	int pnp_register_driver(struct pnp_driver *drv)
213	205	{
214		- int count;
215		-
216	206	pnp_dbg("the driver '%s' has been registered", drv->name);
217	207
218	208	drv->driver.name = drv->name;
219	209	drv->driver.bus = &pnp_bus_type;
220	210
221		- count = driver_register(&drv->driver);
222		-
223		- /* get the number of initial matches */
224		- if (count >= 0){
225		- count = 0;
226		- driver_for_each_device(&drv->driver, NULL, &count, count_devices);
227		- }
228		- return count;
	211	+ return driver_register(&drv->driver);
229	212	}
230	213
231	214	void pnp_unregister_driver(struct pnp_driver *drv)