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

[Simon Arlott <simon@fire.lp0.eu>]

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 <simon@fire.lp0.eu>
---
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
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