Re: [PATCH 0/4] ath10k: a few incorrect return handling fix-up

Nicholas Mc Guire
2014-12-30T18:28:47Z

On Tue, 30 Dec 2014, Sergei Shtylyov wrote:

> Hello.
>
> On 12/30/2014 03:20 PM, Nicholas Mc Guire wrote:
>
>> wait_for_completion_timeout does not return negative values so the tests
>> for <= 0 are not needed and the case differentiation in the error handling
>> path unnecessary.
>
> I decided to verify your statement and I saw that it seems wrong.
> do_wait_for_common() can return -ERESTARTSYS and the return value gets
> returned by its callers unchanged.

the -ERESTARTSYS only can be returned if state matches but
wait_for_completion_timemout passes TASK_UNINTERRUPTIBLE
so signal_pending_state will return 0 and never negativ

my understanding of the callchain is:
wait_for_completion_timemout with TASK_UNINTERRUPTIBLE
-> wait_for_common(...TASK_UNINTERRUPTIBLE)
-> __wait_for_common(...TASK_UNINTERRUPTIBLE)
-> do_wait_for_common(...TASK_UNINTERRUPTIBLE)
-> signal_pending_state(TASK_UNINTERRUPTIBLE...)

static inline int signal_pending_state(long state, struct task_struct *p)
{
if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL)))
return 0;

so wait_for_completion_timemout should return 0 or 1 only

>
>> patch was only compile tested x86_64_defconfig + CONFIG_ATH_CARDS=m
>> CONFIG_ATH10K=m
>
>> patch is against linux-next 3.19.0-rc1 -next-20141226
>
> Rather patches. It would have been better to send one patch instead of
> 4 patches with the same name.
>
sorry for that - I had split it into separate patches as it was
in different files - giving them the same name of course was a bit
brain-dead.

please do give it one more look - if the above argument is invalid
I apologize for the noise.

thx!
hofrat