Re: [PATCH 1/4] scsi: core: constify pointer to scsi_host_template

From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: John Garry <john.garry@huawei.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	Avri Altman <avri.altman@wdc.com>,
	Doug Gilbert <dgilbert@interlog.com>,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] scsi: core: constify pointer to scsi_host_template
Date: Fri, 8 Apr 2022 14:32:01 +0200	[thread overview]
Message-ID: <4c3be5b6-50ef-9e9a-6cee-9642df943342@linaro.org> (raw)
In-Reply-To: <2a88a992-641a-b3ff-fe39-7a61fff87cb6@huawei.com>

On 08/04/2022 14:14, John Garry wrote:
> On 08/04/2022 11:30, Krzysztof Kozlowski wrote:
>> Several pointers to 'struct scsi_host_template' do not modify it, so
>> made them const for safety.
>>
> 
> Is this standard practice? What is so special here?

This is standard practice and there is nothing special here. Pointers to
const are preferred because:
1. They add safety if data is actually const. This is not yet the case,
but scsi_host_template allocation could be made const with some effort.
2. The more const variables, the easier function contents and its impact
is to understand. This is actually the biggest benefit when dealing with
code touching different structures.

In general, constifying is a common practice everywhere in the kernel.

Best regards,
Krzysztof