linux-kernel - Re: [PATCH v5 11/14] software node: move small properties inline when copying

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Date:   Thu, 17 Oct 2019 09:04:36 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        platform-driver-x86@...r.kernel.org
Subject: Re: [PATCH v5 11/14] software node: move small properties inline
 when copying

On Fri, Oct 11, 2019 at 04:07:18PM -0700, Dmitry Torokhov wrote:
> When copying/duplicating set of properties, move smaller properties that
> were stored separately directly inside property entry structures. We can
> move:
> 
> - up to 8 bytes from U8 arrays
> - up to 4 words
> - up to 2 double words
> - one U64 value
> - one or 2 strings.
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> ---
>  drivers/base/swnode.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
> index ae4b24ee2a54..546fc1b20095 100644
> --- a/drivers/base/swnode.c
> +++ b/drivers/base/swnode.c
> @@ -277,6 +277,16 @@ static int property_entry_copy_data(struct property_entry *dst,
>  		dst->value = src->value;
>  	}
>  
> +	if (!dst->is_inline && dst->length <= sizeof(dst->value)) {
> +		/* We have an opportunity to move the data inline */
> +		const void *tmp = dst->pointer;
> +
> +		memcpy(&dst->value, tmp, dst->length);
> +		dst->is_inline = true;
> +
> +		kfree(tmp);
> +	}

This chunk needs to be moved to after dst->length is assigned.  I'll
send updated version after I get more feedback.

> +
>  	dst->length = src->length;
>  	dst->type = src->type;
>  	dst->name = kstrdup(src->name, GFP_KERNEL);

Thanks.

-- 
Dmitry