Re: [RFTv2 3/5] ath10k: rework peer accounting

[Kalle Valo <kvalo@qca.qualcomm.com>]

Michal Kazior <michal.kazior@tieto.com> writes:

> On 10 April 2014 08:59, Kalle Valo <kvalo@qca.qualcomm.com> wrote:
>> Michal Kazior <michal.kazior@tieto.com> writes:
>>
>>> It was troublesome to iterate over peers and
>>> perform sleepable calls. This will be necessary
>>> for some upcomming changes to tx flushing.
>>>
>>> Make peer allocation and initial setup
>>> protected by both ar->conf_mutex and
>>> ar->data_lock. This way it's possible to iterate
>>> over peers with conf_mutex and call sleepable
>>> functions.
>>>
>>> Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
>>
>> First comments, but I need to read this much more carefully still:
>>
>>> --- a/drivers/net/wireless/ath/ath10k/core.h
>>> +++ b/drivers/net/wireless/ath/ath10k/core.h
>>> @@ -199,9 +199,14 @@ struct ath10k_dfs_stats {
>>>  #define ATH10K_MAX_NUM_PEER_IDS (1 << 11) /* htt rx_desc limit */
>>>
>>>  struct ath10k_peer {
>>> +     /* protected by conf_mutex + data_lock */
>>>       struct list_head list;
>>
>> This really needs a lot more documentation. And besides, don't we
>> actually want to protect struct ath10k::peers, not this?
>
> Parts of the structure needs to be locked differently.
>
> I suppose we can say we just protect everything with data_lock except
> `struct list_head list` which needs to be write-protected by both
> conf_mutex and data_lock. But then again, addr and vdev_id don't need
> any locking as they are immutable (and set before adding to the list).

I guess this depends from the point of view. In my opinion struct
ath10k::peers is the actual list and that's why the main documentation
needs to be above struct ath10k::peers field. And I would guess that's
there most people check there for documentation first.

But if we have special rules within struct ath10k_peer (excluding the
list field), we can document that within struct ath10k_peer.

-- 
Kalle Valo

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