[PATCH] scsi_debug: Convert to use root_device_register() and root_device_unregister()

[PATCH] scsi_debug: Convert to use root_device_register() and root_device_unregister()

[Nicholas A. Bellinger]

From: Nicholas Bellinger <nab@linux-iscsi.org>

Hi Doug and Co,

This patch updates the scsi_debug virtual LLD to use root_device_register()
and root_device_unregister() from include/linux/device.h instead of device_register()
and device_unregister() respectively within scsi_debug_init() and scsi_debug_exit()
This simply involved converting the static struct device pseudo_primary into a
pointer that is setup by the call to root_device_register().

Thanks to Richard Sharpe and Dmitry Torokhov for their help with this item.

Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
---
 drivers/scsi/scsi_debug.c |   26 ++++++++------------------
 1 files changed, 8 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index b02bdc6..399c430 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -3207,23 +3207,14 @@ static void do_remove_driverfs_files(void)
 	driver_remove_file(&sdebug_driverfs_driver, &driver_attr_add_host);
 }
 
-static void pseudo_0_release(struct device *dev)
-{
-	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
-		printk(KERN_INFO "scsi_debug: pseudo_0_release() called\n");
-}
-
-static struct device pseudo_primary = {
-	.init_name	= "pseudo_0",
-	.release	= pseudo_0_release,
-};
+struct device *pseudo_primary;
 
 static int __init scsi_debug_init(void)
 {
 	unsigned long sz;
 	int host_to_add;
 	int k;
-	int ret;
+	int ret = 0;
 
 	switch (scsi_debug_sector_size) {
 	case  512:
@@ -3352,10 +3343,9 @@ static int __init scsi_debug_init(void)
 			map_region(0, 2);
 	}
 
-	ret = device_register(&pseudo_primary);
-	if (ret < 0) {
-		printk(KERN_WARNING "scsi_debug: device_register error: %d\n",
-			ret);
+	pseudo_primary = root_device_register("pseudo_0");
+	if (!(pseudo_primary)) {
+		printk(KERN_WARNING "scsi_debug: root_device_register() error\n");
 		goto free_vm;
 	}
 	ret = bus_register(&pseudo_lld_bus);
@@ -3402,7 +3392,7 @@ del_files:
 bus_unreg:
 	bus_unregister(&pseudo_lld_bus);
 dev_unreg:
-	device_unregister(&pseudo_primary);
+	root_device_unregister(pseudo_primary);
 free_vm:
 	if (map_storep)
 		vfree(map_storep);
@@ -3423,7 +3413,7 @@ static void __exit scsi_debug_exit(void)
 	do_remove_driverfs_files();
 	driver_unregister(&sdebug_driverfs_driver);
 	bus_unregister(&pseudo_lld_bus);
-	device_unregister(&pseudo_primary);
+	root_device_unregister(pseudo_primary);
 
 	if (dif_storep)
 		vfree(dif_storep);
@@ -3474,7 +3464,7 @@ static int sdebug_add_adapter(void)
         spin_unlock(&sdebug_host_list_lock);
 
         sdbg_host->dev.bus = &pseudo_lld_bus;
-        sdbg_host->dev.parent = &pseudo_primary;
+        sdbg_host->dev.parent = pseudo_primary;
         sdbg_host->dev.release = &sdebug_release_adapter;
         dev_set_name(&sdbg_host->dev, "adapter%d", scsi_debug_add_host);
 
-- 
1.5.6.5

Re: [PATCH] scsi_debug: Convert to use root_device_register() and root_device_unregister()

[Nicholas A. Bellinger]

On Mon, 2010-09-06 at 16:41 -0700, Dmitry Torokhov wrote:
> On Mon, Sep 06, 2010 at 03:32:20PM -0700, Nicholas A. Bellinger wrote:
> >  static int __init scsi_debug_init(void)
> >  {
> >  	unsigned long sz;
> >  	int host_to_add;
> >  	int k;
> > -	int ret;
> > +	int ret = 0;
> >  
> 
> Please do not initialize error condition with success; when adding
> additional initialization it makes easy to miss assigning proper return
> value (as you seem to have) and return success in case of failure.

The reason this was added because my gcc (Debian 4.3.2-1.1) 4.3.2
complained about this being possibily uninitialized..

> 
> >  	switch (scsi_debug_sector_size) {
> >  	case  512:
> > @@ -3352,10 +3343,9 @@ static int __init scsi_debug_init(void)
> >  			map_region(0, 2);
> >  	}
> >  
> > -	ret = device_register(&pseudo_primary);
> > -	if (ret < 0) {
> > -		printk(KERN_WARNING "scsi_debug: device_register error: %d\n",
> > -			ret);
> > +	pseudo_primary = root_device_register("pseudo_0");
> > +	if (!(pseudo_primary)) {
> 
> root_device_register() returns ERR_PTR-encoded error codes, you should
> do:
> 
> 	if (IS_ERR(pseudo_primary)) {
> 		printk(KERN_WARNING "scsi_debug: root_device_register() error\n");
> 		ret = PTR_ERR(pseudo_primary);
> 		goto free_vm;
> 	}
> 
> Same goes for your other patch.

<nod> Updating that now.

Thanks,

--nab

Re: [PATCH] scsi_debug: Convert to use root_device_register() and root_device_unregister()

[Dmitry Torokhov]

On Mon, Sep 06, 2010 at 03:32:20PM -0700, Nicholas A. Bellinger wrote:
>  static int __init scsi_debug_init(void)
>  {
>  	unsigned long sz;
>  	int host_to_add;
>  	int k;
> -	int ret;
> +	int ret = 0;
>  

Please do not initialize error condition with success; when adding
additional initialization it makes easy to miss assigning proper return
value (as you seem to have) and return success in case of failure.

>  	switch (scsi_debug_sector_size) {
>  	case  512:
> @@ -3352,10 +3343,9 @@ static int __init scsi_debug_init(void)
>  			map_region(0, 2);
>  	}
>  
> -	ret = device_register(&pseudo_primary);
> -	if (ret < 0) {
> -		printk(KERN_WARNING "scsi_debug: device_register error: %d\n",
> -			ret);
> +	pseudo_primary = root_device_register("pseudo_0");
> +	if (!(pseudo_primary)) {

root_device_register() returns ERR_PTR-encoded error codes, you should
do:

	if (IS_ERR(pseudo_primary)) {
		printk(KERN_WARNING "scsi_debug: root_device_register() error\n");
		ret = PTR_ERR(pseudo_primary);
		goto free_vm;
	}

Same goes for your other patch.

Thanks.

-- 
Dmitry

Re: [PATCH] scsi_debug: Convert to use root_device_register() and root_device_unregister()

[Dmitry Torokhov]

On Mon, Sep 06, 2010 at 04:39:14PM -0700, Nicholas A. Bellinger wrote:
> On Mon, 2010-09-06 at 16:41 -0700, Dmitry Torokhov wrote:
> > On Mon, Sep 06, 2010 at 03:32:20PM -0700, Nicholas A. Bellinger wrote:
> > >  static int __init scsi_debug_init(void)
> > >  {
> > >  	unsigned long sz;
> > >  	int host_to_add;
> > >  	int k;
> > > -	int ret;
> > > +	int ret = 0;
> > >  
> > 
> > Please do not initialize error condition with success; when adding
> > additional initialization it makes easy to miss assigning proper return
> > value (as you seem to have) and return success in case of failure.
> 
> The reason this was added because my gcc (Debian 4.3.2-1.1) 4.3.2
> complained about this being possibily uninitialized..
> 

And rightly so - you did not assign a value to it when handling
root_device_register() failure. Compiler warnings are generally there
for a reason, not just a nuisance that should be shut off without a
second thought.

-- 
Dmitry