On Tuesday 12 December 2017 08:28 PM, Geert Uytterhoeven wrote:
> Hi Shrikant,
>
> On Tue, Dec 12, 2017 at 2:45 PM, <[email protected]> wrote:
>> From: Shrikant Maurya <[email protected]>
>>
>> As reported by Jia-Ju Bai (https://lkml.org/lkml/2017/12/11/872):
>> API's are using GFP_KERNEL to allocate memory which may sleep.
>>
>> To ensure atomicity such allocations must be avoided in critical
>> sections under spinlock.
>> Fixed by replacing GFP_KERNEL to GFP_ATOMIC.
>>
>> Reported-by: Jia-Ju Bai <[email protected]>
>> Signed-off-by: Shrikant Maurya <[email protected]>
>> Signed-off-by: Suniel Mahesh <[email protected]>
>> Signed-off-by: Raghu Bharadwaj <[email protected]>
>> Signed-off-by: Karthik Tummala <[email protected]>
>
> Can't the call to device_init_wakeup() in isp116x_start() just be moved
> below the spinlock release?
Can't move it below the spinlock.
Value going to be written into HcRhStatus register depends on it:
isp116x_write_reg32(isp116x, HCRHSTATUS, val);
Instead we can move it before the spinlock.
>
>> --- a/drivers/base/power/wakeup.c
>> +++ b/drivers/base/power/wakeup.c
>> @@ -92,11 +92,11 @@ struct wakeup_source *wakeup_source_create(const char
>> *name)
>> {
>> struct wakeup_source *ws;
>>
>> - ws = kmalloc(sizeof(*ws), GFP_KERNEL);
>> + ws = kmalloc(sizeof(*ws), GFP_ATOMIC);
>
> With GFP_ATOMIC, allocation failure is much more likely to occur.
> So IMHO it's better to fix the isp116x, than to impose this burden on
> every user.
Absolutely. Thanks for pointing it out, it's not the right solution.
>
>> if (!ws)
>> return NULL;
>>
>> - wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) :
>> NULL);
>> + wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_ATOMIC) :
>> NULL);
>> return ws;
>> }
>> EXPORT_SYMBOL_GPL(wakeup_source_create);
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> [email protected]
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like
> that.
> -- Linus Torvalds
>
Thank you Geert.
--
Shrikant
techveda.org
