LinuxLists.cc - [PATCH] dvb-core: Handle failures to create devices

2007-05-01 17:12:34

Subject: [PATCH] dvb-core: Handle failures to create devices

2007-05-01 17:14:13

Subject: Re: [PATCH] dvb-core: Handle failures to create devices

On 01/05/07 18:12, Simon Arlott wrote:
> dvb_class is NULL, this runs dvb_init using subsys_initclass instead of
> module_init.

That should of course be subsystem_initCALL not "initclass".

--
Simon Arlott

2007-05-01 21:21:21

by Trent Piepho

[permalink] [raw]

Subject: Re: [linux-dvb] [PATCH] dvb-core: Handle failures to create devices

On Tue, 1 May 2007, Simon Arlott wrote:
> dvb-core is not started early enough when device drivers that use dvb are
> compiled in so device_register_device fails (silently) since dvb_class is
> NULL, this runs dvb_init using subsys_initclass instead of module_init.
>
> dvb_register_device will now check the return value of class_device_create.

Good catch.

> + printk("%s: failed to create device dvb%d.%s%d (%ld)\n", __FUNCTION__,
> + adap->num, dnames[type], id, PTR_ERR(clsdev));
> + return PTR_ERR(clsdev);

printk(KERN_ERR "...."

2007-05-01 21:33:10

by Simon Arlott

[permalink] [raw]

Subject: Re: [linux-dvb] [PATCH] dvb-core: Handle failures to create devices

dvb-core is not started early enough when device drivers that use dvb are
compiled in so device_register_device fails (silently) since dvb_class is
NULL, this runs dvb_init using subsys_initcall instead of module_init.

dvb_register_device will now check the return value of class_device_create.
All the printks had missing level prefixes so I've fixed these too.

Signed-off-by: Simon Arlott <[email protected]>
---
On 01/05/07 22:21, Trent Piepho wrote:
> On Tue, 1 May 2007, Simon Arlott wrote:
>> dvb-core is not started early enough when device drivers that use dvb are
>> compiled in so device_register_device fails (silently) since dvb_class is
>> NULL, this runs dvb_init using subsys_initclass instead of module_init.
>>
>> dvb_register_device will now check the return value of class_device_create.
>
> Good catch.

Thanks, it's only been 11 months since I first pointed it out.

>> + printk("%s: failed to create device dvb%d.%s%d (%ld)\n", __FUNCTION__,
>> + adap->num, dnames[type], id, PTR_ERR(clsdev));
>> + return PTR_ERR(clsdev);
>
> printk(KERN_ERR "...."

I copied another printk from that file without thinking.

drivers/media/dvb/dvb-core/dvbdev.c | 21 ++++++++++++++-------
1 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/media/dvb/dvb-core/dvbdev.c b/drivers/media/dvb/dvb-core/dvbdev.c
index 7683983..297da62 100644
--- a/drivers/media/dvb/dvb-core/dvbdev.c
+++ b/drivers/media/dvb/dvb-core/dvbdev.c
@@ -201,6 +201,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
struct dvb_device *dvbdev;
struct file_operations *dvbdevfops;

+ struct class_device *clsdev;
int id;

mutex_lock(&dvbdev_register_lock);
@@ -208,7 +209,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
if ((id = dvbdev_get_free_id (adap, type)) < 0){
mutex_unlock(&dvbdev_register_lock);
*pdvbdev = NULL;
- printk ("%s: could get find free device id...\n", __FUNCTION__);
+ printk(KERN_ERR "%s: could get find free device id...\n", __FUNCTION__);
return -ENFILE;
}

@@ -242,10 +243,16 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,

mutex_unlock(&dvbdev_register_lock);

- class_device_create(dvb_class, NULL, MKDEV(DVB_MAJOR, nums2minor(adap->num, type, id)),
+ clsdev = class_device_create(dvb_class, NULL, MKDEV(DVB_MAJOR, nums2minor(adap->num, type, id)),
adap->device, "dvb%d.%s%d", adap->num, dnames[type], id);

- dprintk("DVB: register adapter%d/%s%d @ minor: %i (0x%02x)\n",
+ if (IS_ERR(clsdev)) {
+ printk(KERN_ERR "%s: failed to create device dvb%d.%s%d (%ld)\n", __FUNCTION__,
+ adap->num, dnames[type], id, PTR_ERR(clsdev));
+ return PTR_ERR(clsdev);
+ }
+
+ dprintk(KERN_DEBUG "DVB: register adapter%d/%s%d @ minor: %i (0x%02x)\n",
adap->num, dnames[type], id, nums2minor(adap->num, type, id),
nums2minor(adap->num, type, id));

@@ -304,7 +311,7 @@ int dvb_register_adapter(struct dvb_adapter *adap, const char *name, struct modu
memset (adap, 0, sizeof(struct dvb_adapter));
INIT_LIST_HEAD (&adap->device_list);

- printk ("DVB: registering new adapter (%s).\n", name);
+ printk(KERN_INFO "DVB: registering new adapter (%s).\n", name);

adap->num = num;
adap->name = name;
@@ -400,13 +407,13 @@ static int __init init_dvbdev(void)
dev_t dev = MKDEV(DVB_MAJOR, 0);

if ((retval = register_chrdev_region(dev, MAX_DVB_MINORS, "DVB")) != 0) {
- printk("dvb-core: unable to get major %d\n", DVB_MAJOR);
+ printk(KERN_ERR "dvb-core: unable to get major %d\n", DVB_MAJOR);
return retval;
}

cdev_init(&dvb_device_cdev, &dvb_device_fops);
if ((retval = cdev_add(&dvb_device_cdev, dev, MAX_DVB_MINORS)) != 0) {
- printk("dvb-core: unable to get major %d\n", DVB_MAJOR);
+ printk(KERN_ERR "dvb-core: unable to get major %d\n", DVB_MAJOR);
goto error;
}

@@ -431,7 +438,7 @@ static void __exit exit_dvbdev(void)
unregister_chrdev_region(MKDEV(DVB_MAJOR, 0), MAX_DVB_MINORS);
}

-module_init(init_dvbdev);
+subsys_initcall(init_dvbdev);
module_exit(exit_dvbdev);

MODULE_DESCRIPTION("DVB Core Driver");
--
1.5.0.1

--
Simon Arlott
09F911029D74E35BD84156C5635688C0

2007-05-06 22:50:35

by Trent Piepho

[permalink] [raw]

Subject: Re: [linux-dvb] [PATCH] dvb-core: Handle failures to create devices

I've tested this and can confirm it works. dvb_class will be set too late
without the change to subsys_initcall.

On Tue, 1 May 2007, Simon Arlott wrote:
> dvb-core is not started early enough when device drivers that use dvb are
> compiled in so device_register_device fails (silently) since dvb_class is

^dvb_register_device

> NULL, this runs dvb_init using subsys_initcall instead of module_init.
>
> dvb_register_device will now check the return value of class_device_create.
> All the printks had missing level prefixes so I've fixed these too.

Probably better to make this a separate patch, since it's not related.

> - printk ("%s: could get find free device id...\n", __FUNCTION__);
> + printk(KERN_ERR "%s: could get find free device id...\n", __FUNCTION__);

"couldn't find free device id"

If it's ok with you, I'll import your patch as two seperate patches with
the spelling errors fixed?

> + dprintk(KERN_DEBUG "DVB: register adapter%d/%s%d @ minor: %i (0x%02x)\n",
> adap->num, dnames[type], id, nums2minor(adap->num, type, id),
> nums2minor(adap->num, type, id));

The dvb-core dvbdev_debug parameter does nothing but turn on this one
single dprintk. I'm tempted to just delete it.

2007-05-06 22:58:33

by Simon Arlott

[permalink] [raw]

Subject: Re: [linux-dvb] [PATCH] dvb-core: Handle failures to create devices

On 06/05/07 23:50, Trent Piepho wrote:
> I've tested this and can confirm it works. dvb_class will be set too late
> without the change to subsys_initcall.
>
> On Tue, 1 May 2007, Simon Arlott wrote:
>> dvb-core is not started early enough when device drivers that use dvb are
>> compiled in so device_register_device fails (silently) since dvb_class is
>
> ^dvb_register_device
>
>> NULL, this runs dvb_init using subsys_initcall instead of module_init.
>>
>> dvb_register_device will now check the return value of class_device_create.
>> All the printks had missing level prefixes so I've fixed these too.
>
> Probably better to make this a separate patch, since it's not related.
>
>> - printk ("%s: could get find free device id...\n", __FUNCTION__);
>> + printk(KERN_ERR "%s: could get find free device id...\n", __FUNCTION__);
>
> "couldn't find free device id"
>
> If it's ok with you, I'll import your patch as two seperate patches with
> the spelling errors fixed?

That's fine with me.

>> + dprintk(KERN_DEBUG "DVB: register adapter%d/%s%d @ minor: %i (0x%02x)\n",
>> adap->num, dnames[type], id, nums2minor(adap->num, type, id),
>> nums2minor(adap->num, type, id));
>
> The dvb-core dvbdev_debug parameter does nothing but turn on this one
> single dprintk. I'm tempted to just delete it.

Just always output that information, or remove it? (I have it enabled,
although I'm not sure if there's any point).

--
Simon Arlott