netdev - Re: [PATCH iwl-next v2] ice: split ice_aq_wait_for

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Message-ID: <ZM0MlhZduLVa6YZV@kernel.org>
Date: Fri, 4 Aug 2023 16:35:02 +0200
From: Simon Horman <horms@...nel.org>
To: Przemek Kitszel <przemyslaw.kitszel@...el.com>
Cc: intel-wired-lan@...ts.osuosl.org,
	Tony Nguyen <anthony.l.nguyen@...el.com>, netdev@...r.kernel.org,
	Jacob Keller <jacob.e.keller@...el.com>,
	Jesse Brandeburg <jesse.brandeburg@...el.com>
Subject: Re: [PATCH iwl-next v2] ice: split ice_aq_wait_for_event() func into
 two

On Thu, Aug 03, 2023 at 11:13:47AM -0400, Przemek Kitszel wrote:
> Mitigate race between registering on wait list and receiving
> AQ Response from FW.
> 
> ice_aq_prep_for_event() should be called before sending AQ command,
> ice_aq_wait_for_event() should be called after sending AQ command,
> to wait for AQ Response.
> 
> struct ice_aq_task is exposed to callers, what takes burden of memory
> ownership out from AQ-wait family of functions.
> 
> Embed struct ice_rq_event_info event into struct ice_aq_task
> (instead of it being a ptr), to remove some more code from the callers.
> 
> Additional fix: one of the checks in ice_aq_check_events() was off by one.

Hi Przemek,

This patch seems to be doing three things:

1. Refactoring code, in order to allow
2. Addressing a race condition
3. Correcting an off-by-one error

All good stuff. But all complex, and 1 somewhat buries 2 and 3.
I'm wondering if the patch could be broken up into smaller patches
to aid both review new and inspection later.

The above notwithstanding, the code does seems fine to me.

> Please note, that this was found by reading the code,
> an actual race has not yet materialized.

Sure. But I do wonder if a fixes tag might be appropriate anyway.

> Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@...el.com>