linux-kernel - Re: [PATCH v7 5/8] x86/e820: Refactor e820__range

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Date:   Tue, 26 Apr 2022 14:37:49 -0300
From:   Martin Fernandez <martin.fernandez@...ypsium.com>
To:     Dave Hansen <dave.hansen@...el.com>
Cc:     linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
        platform-driver-x86@...r.kernel.org, linux-mm@...ck.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
        ardb@...nel.org, dvhart@...radead.org, andy@...radead.org,
        gregkh@...uxfoundation.org, rafael@...nel.org, rppt@...nel.org,
        akpm@...ux-foundation.org, daniel.gutson@...ypsium.com,
        hughsient@...il.com, alex.bazhaniuk@...ypsium.com,
        alison.schofield@...el.com, keescook@...omium.org
Subject: Re: [PATCH v7 5/8] x86/e820: Refactor e820__range_remove

On 4/26/22, Dave Hansen <dave.hansen@...el.com> wrote:
> On 4/25/22 10:15, Martin Fernandez wrote:
>> +/**
>> + * e820__range_remove() - Remove an address range from e820_table.
>> + * @start: Start of the address range.
>> + * @size: Size of the address range.
>> + * @old_type: Type of the entries that we want to remove.
>> + * @check_type: Bool to decide if ignore @old_type or not.
>> + *
>> + * Remove [@start, @start + @size) from e820_table. If @check_type is
>> + * true remove only entries with type @old_type.
>> + *
>> + * Return: The size removed.
>> + */
>
> The refactoring looks promising.  But, there's a *LOT* of kerneldoc
> noise, like:
>
>> + * @table: Target e820_table.
>> + * @start: Start of the range.
>> + * @size: Size of the range.
>
> and this:
>
>> + * struct e820_type_updater_data - Helper type for
>> + * __e820__range_update().
>> + * @old_type: old_type parameter of __e820__range_update().
>> + * @new_type: new_type parameter of __e820__range_update().
>
> Those are just a pure waste of bytes.  I suspect some more judicious
> function comments would also make the diffstat look more palatable.
>

I can get rid off of the kerneldocs and just put normal comments for some
functions that really need them.

> Also, in general, the naming is a bit verbose.  You might want to trim
> some of those names down, like:
>
>> +static bool __init crypto_updater__should_update(const struct e820_entry
>> *entry,
>> +						 const void *data)
>> +{
>> +	const struct e820_crypto_updater_data *crypto_updater_data =
>> +		(const struct e820_crypto_updater_data *)data;
>

Yes I agree on this. Do you have any suggestions for these kind of
functions? I want to explicitly state that these functions are in some of
namespace and are different of the other ones.

In the end I don't think this is very harmful since these functions are one-time
used (in a single place), is not the case that you have to use them everywhere..

> Those are just some high-level comments.  This also needs some really
> careful review of the refactoring to make sure that it doesn't break any
> of the existing e820 users.
>

I'm glad to hear more people's thoughts on this. Thanks for the feedback.