linux-kernel - Re: [PATCH v6 4/4] media: chips-media: wave5: Improve performance of decoder

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Message-ID: <018ef330788ac4d5f3cc6a9b9b98578eefabbbb9.camel@collabora.com>
Date: Mon, 17 Nov 2025 08:45:27 -0500
From: Nicolas Dufresne <nicolas.dufresne@...labora.com>
To: "jackson.lee" <jackson.lee@...psnmedia.com>, "mchehab@...nel.org"	
 <mchehab@...nel.org>, "hverkuil-cisco@...all.nl"
 <hverkuil-cisco@...all.nl>,  "bob.beckett@...labora.com"	
 <bob.beckett@...labora.com>
Cc: "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>, 
 "linux-kernel@...r.kernel.org"	 <linux-kernel@...r.kernel.org>,
 "lafley.kim" <lafley.kim@...psnmedia.com>,  "b-brnich@...com"	
 <b-brnich@...com>, "hverkuil@...all.nl" <hverkuil@...all.nl>, Nas Chung	
 <nas.chung@...psnmedia.com>
Subject: Re: [PATCH v6 4/4] media: chips-media: wave5: Improve performance
 of decoder

Hi,

Le lundi 17 novembre 2025 à 02:07 +0000, jackson.lee a écrit :
> > >  		} else {
> > > +			spin_lock_irqsave(&inst->state_spinlock, flags);
> > 
> > Move the locking inside the set_state function.
> > 
> > cheers,
> > Nicolas
> 
> I think the locking should not be move into the set_state
> function(switch_state).
> Because the send_eos_event, handle_dynamic_resolution_change and
> flag_last_buffer_done already have the lockdep_assert_held(&inst-
> >state_spinlock); inside those function,
> So to concisify the above code, even if the locking is moved into
> switch_statue, the locking should be called again outside.

My suggestion is to try and reduce code redundancy, another method commonly used
is to have a small version of the function that takes the locking, this you can
turn 3 lines into one in many places.

Nicolas

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