On 2017-07-30, at 2:53 PM, Helge Deller wrote:
> On 30.07.2017 20:37, James Bottomley wrote:
>> On Sun, 2017-07-30 at 14:21 -0400, John David Anglin wrote:
>>> On 2017-07-30, at 2:12 PM, Meelis Roos wrote:
>>>
>>>>
>>>>>
>>>>> How about this? There's no need to take the write lock when
>>>>> creating
>>>>> links anyway.
>>>>
>>>> No effect.
>>>
>>> Is the backtrace still the same?
>>
>> There's another write lock over a symlink in
>> pdcs_register_pathentries() does moving it up as well finally make this
>> go away (cumulative patch below). If that doesn't work, enabling
>> DEBUG_PREEMPT might show which lock is the problem.
>
>
> That patch works.
Same here.
I noticed that when CONFIG_PDC_STABLE=m, it appears the PDC stable links are not setup.
The "PDC Stable Storage facility v0.30" message doesn't appear in the console output.
>
> Helge
>
>> diff --git a/drivers/parisc/pdc_stable.c b/drivers/parisc/pdc_stable.c
>> index 7147aa53e9a2..3e0c90420a1b 100644
>> --- a/drivers/parisc/pdc_stable.c
>> +++ b/drivers/parisc/pdc_stable.c
>> @@ -331,13 +331,13 @@ pdcspath_hwpath_write(struct pdcspath_entry *entry, const char *buf, size_t coun
>> /* Now, dive in. Write back to the hardware */
>> pdcspath_store(entry);
>>
>> + write_unlock(&entry->rw_lock);
>> +
>> /* Update the symlink to the real device */
>> sysfs_remove_link(&entry->kobj, "device");
>> ret = sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
>> WARN_ON(ret);
>>
>> - write_unlock(&entry->rw_lock);
>> -
>> printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n",
>> entry->name, buf);
>>
>> @@ -998,6 +998,7 @@ pdcs_register_pathentries(void)
>> /* kobject is now registered */
>> write_lock(&entry->rw_lock);
>> entry->ready = 2;
>> + write_unlock(&entry->rw_lock);
>>
>> /* Add a nice symlink to the real device */
>> if (entry->dev) {
>> @@ -1005,7 +1006,6 @@ pdcs_register_pathentries(void)
>> WARN_ON(err);
>> }
>>
>> - write_unlock(&entry->rw_lock);
>> kobject_uevent(&entry->kobj, KOBJ_ADD);
>> }
Dave
--
John David Anglin dave.anglin@xxxxxxxx
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