Re: [KJ][PATCH] Correct misc_register return code handling in several drivers

[Neil Horman]

On Mon, Oct 23, 2006 at 06:39:24PM +0100, Alan Cox wrote:
> Ar Llu, 2006-10-23 am 13:19 -0400, ysgrifennodd Neil Horman:
> > +	for_each_online_node(node) {
> > +		if(timers[node] != NULL)
> > +			kfree(timers[node]);
> > +	}
> 
> The if test appears to be redundant as kfree(NULL) is a valid no-op.
> 
> > +	if (misc_register(&hp_sdc_rtc_dev) != 0)
> > +		printk(KERN_INFO "Could not register misc. dev for sdc\n");
> 
> Many users will misconstrue this has a hard disk name - is there a
> better name to use.
> 
> >  	if (ret)
> >  		printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
> 
> These all really show that we should pass the name into the misc
> register and do the printk there to cut down on random name variants and
> kernel size. Separate problem, just noting it in case someone feels
> inspired 8)
> 
> Alan

New patch attached, taking Alan's suggestions into account.  I'll consolidate
the printk error messages into misc_register in a later patch when I have a
moment.  Thanks Alan.

Regards
Neil


Signed-off-by: Neil Horman <nhorman@xxxxxxxxxxxxx>

 drivers/char/mmtimer.c          |   28 ++++++++++++++++++++++------
 drivers/char/tpm/tpm.c          |    1 +
 drivers/input/misc/hp_sdc_rtc.c |    6 +++++-
 drivers/macintosh/apm_emu.c     |    5 ++++-
 drivers/net/tun.c               |    2 ++
 fs/dlm/user.c                   |    1 +
 6 files changed, 35 insertions(+), 8 deletions(-)



diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
--- a/drivers/char/mmtimer.c
+++ b/drivers/char/mmtimer.c
@@ -669,6 +669,7 @@ static struct k_clock sgi_clock = {
 static int __init mmtimer_init(void)
 {
 	unsigned i;
+	int err = -1;
 	cnodeid_t node, maxn = -1;
 
 	if (!ia64_platform_is("sn2"))
@@ -680,7 +681,7 @@ static int __init mmtimer_init(void)
 	if (sn_rtc_cycles_per_second < 100000) {
 		printk(KERN_ERR "%s: unable to determine clock frequency\n",
 		       MMTIMER_NAME);
-		return -1;
+		goto out;
 	}
 
 	mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
@@ -689,13 +690,13 @@ static int __init mmtimer_init(void)
 	if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) {
 		printk(KERN_WARNING "%s: unable to allocate interrupt.",
 			MMTIMER_NAME);
-		return -1;
+		goto out;
 	}
 
 	if (misc_register(&mmtimer_miscdev)) {
 		printk(KERN_ERR "%s: failed to register device\n",
 		       MMTIMER_NAME);
-		return -1;
+		goto out1;
 	}
 
 	/* Get max numbered node, calculate slots needed */
@@ -709,16 +710,18 @@ static int __init mmtimer_init(void)
 	if (timers == NULL) {
 		printk(KERN_ERR "%s: failed to allocate memory for device\n",
 				MMTIMER_NAME);
-		return -1;
+		goto out2;
 	}
 
+	memset(timers,0,(sizeof(mmtimer_t *)*maxn));
+
 	/* Allocate mmtimer_t's for each online node */
 	for_each_online_node(node) {
 		timers[node] = kmalloc_node(sizeof(mmtimer_t)*NUM_COMPARATORS, GFP_KERNEL, node);
 		if (timers[node] == NULL) {
 			printk(KERN_ERR "%s: failed to allocate memory for device\n",
 				MMTIMER_NAME);
-			return -1;
+			goto out3;
 		}
 		for (i=0; i< NUM_COMPARATORS; i++) {
 			mmtimer_t * base = timers[node] + i;
@@ -738,7 +741,20 @@ static int __init mmtimer_init(void)
 	printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION,
 	       sn_rtc_cycles_per_second/(unsigned long)1E6);
 
-	return 0;
+	err = 0;
+out:
+	return err;
+
+out3:
+	for_each_online_node(node) {
+		kfree(timers[node]);
+	}
+out2:
+	misc_deregister(&mmtimer_miscdev);
+out1:
+	free_irq(SGI_MMTIMER_VECTOR, NULL);
+	goto out;
+	
 }
 
 module_init(mmtimer_init);
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -1155,6 +1155,7 @@ #define DEVNAME_SIZE 7
 
 	if (sysfs_create_group(&dev->kobj, chip->vendor.attr_group)) {
 		list_del(&chip->list);
+		misc_deregister(&chip->vendor.miscdev);
 		put_device(dev);
 		clear_bit(chip->dev_num, dev_mask);
 		kfree(chip);
diff --git a/drivers/input/misc/hp_sdc_rtc.c b/drivers/input/misc/hp_sdc_rtc.c
--- a/drivers/input/misc/hp_sdc_rtc.c
+++ b/drivers/input/misc/hp_sdc_rtc.c
@@ -693,9 +693,13 @@ static int __init hp_sdc_rtc_init(void)
 
 	init_MUTEX(&i8042tregs);
 
+	INIT_LIST_HEAD(&hp_sdc_rtc_dev.list);
+
 	if ((ret = hp_sdc_request_timer_irq(&hp_sdc_rtc_isr)))
 		return ret;
-	misc_register(&hp_sdc_rtc_dev);
+	if (misc_register(&hp_sdc_rtc_dev) != 0)
+		printk(KERN_INFO "Could not register misc. dev for i8042 rtc\n");
+
         create_proc_read_entry ("driver/rtc", 0, NULL,
 				hp_sdc_rtc_read_proc, NULL);
 
diff --git a/drivers/macintosh/apm_emu.c b/drivers/macintosh/apm_emu.c
--- a/drivers/macintosh/apm_emu.c
+++ b/drivers/macintosh/apm_emu.c
@@ -520,6 +520,8 @@ static int __init apm_emu_init(void)
 {
 	struct proc_dir_entry *apm_proc;
 
+	INIT_LIST_HEAD(&apm_device.list);
+
 	if (sys_ctrler != SYS_CTRLER_PMU) {
 		printk(KERN_INFO "apm_emu: Requires a machine with a PMU.\n");
 		return -ENODEV;
@@ -529,7 +531,8 @@ static int __init apm_emu_init(void)
 	if (apm_proc)
 		apm_proc->owner = THIS_MODULE;
 
-	misc_register(&apm_device);
+	if (misc_register(&apm_device) != 0)
+		printk(KERN_INFO "Could not create misc. device for apm\n");
 
 	pmu_register_sleep_notifier(&apm_sleep_notifier);
 
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -856,6 +856,8 @@ static int __init tun_init(void)
 	printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
 	printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
 
+	INIT_LIST_HEAD(&tun_miscdev.list);
+
 	ret = misc_register(&tun_miscdev);
 	if (ret)
 		printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -773,6 +773,7 @@ int dlm_user_init(void)
 	ctl_device.name = "dlm-control";
 	ctl_device.fops = &ctl_device_fops;
 	ctl_device.minor = MISC_DYNAMIC_MINOR;
+	INIT_LIST_HEAD(&ctl_device.list);
 
 	error = misc_register(&ctl_device);
 	if (error)
-- 
/***************************************************
 *Neil Horman
 *Software Engineer
 *gpg keyid: 1024D / 0x92A74FA1 - http://pgp.mit.edu
 ***************************************************/
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