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Date: Mon, 18 Dec 2023 16:26:04 +0000
From: Simon Horman <horms@kernel.org>
To: Suman Ghosh <sumang@marvell.com>
Cc: "davem@davemloft.net" <davem@davemloft.net>,
	"edumazet@google.com" <edumazet@google.com>,
	"kuba@kernel.org" <kuba@kernel.org>,
	"pabeni@redhat.com" <pabeni@redhat.com>,
	Sunil Kovvuri Goutham <sgoutham@marvell.com>,
	Subbaraya Sundeep Bhatta <sbhatta@marvell.com>,
	Jerin Jacob Kollanukkaran <jerinj@marvell.com>,
	Geethasowjanya Akula <gakula@marvell.com>,
	Hariprasad Kelam <hkelam@marvell.com>,
	Linu Cherian <lcherian@marvell.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [EXT] Re: [net PATCH] octeontx2-pf: Fix graceful exit during PFC
 configuration failure
Message-ID: <20231218162604.GH6288@kernel.org>
References: <20231213181044.103943-1-sumang@marvell.com>
 <20231215125043.GJ6288@kernel.org>
 <SJ0PR18MB52169B706EB4F8F8D8FAB20CDB91A@SJ0PR18MB5216.namprd18.prod.outlook.com>
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On Sun, Dec 17, 2023 at 06:26:24AM +0000, Suman Ghosh wrote:

...

> >Perhaps I am on the wrong track here, but if
> >1. otx2_pfc_txschq_stop() was called by otx2_pfc_txschq_update()
> >   (or otx2_pfc_txschq_config()) for relevant error cases; and
> >2. pfc_en was passed as a parameter to otx2_config_priority_flow_ctrl()
> >
> >Then I think that the unwind logic in the if condition above could
> >be expressed as unwind ladder with goto labels whereby the order
> >of unwinding is strictly the reverse of configuration.
> >
> >This is a subjective opinion, but the advantage of this approach is that
> >it
> >tends to lead to more maintainable code and fewer errors in... error
> >paths.
> >
> >(Completely untested!)
> >
> >	...
> >	if (err)
> >		goto err_pfc_en;
> >	...
> >	err = otx2_pfc_txschq_update(pfvf);
> >	if (err)
> >		goto err_config;
> >
> >	return 0;
> >
> >err_config:
> >	if (pfc->pfc_en)
> >		otx2_nix_config_bp(pfvf, false);
> >	otx2_config_priority_flow_ctrl(pfvf, old_pfc_en);
> >err_pfc_en:
> >	pfvf->pfc_en = old_pfc_en;
> >
> >	return err;
> [Suman] Let me think through it. I need to check if some cases will be missed, will update, and push a new patch in that case. Thanks for your feedback, Simon!!

Thanks, much appreciated.