Re: [PATCH 2/4] ptp: use kcalloc/kmallco_array when allocating arrays

Richard Cochran
2017-02-14T08:38:57Z

On Mon, Feb 13, 2017 at 07:51:06PM -0800, Dmitry Torokhov wrote:
> @@ -269,13 +269,13 @@ static int ptp_populate_pins(struct ptp_clock *ptp)
> struct ptp_clock_info *info = ptp->info;
> int err = -ENOMEM, i, n_pins = info->n_pins;
>
> - ptp->pin_dev_attr = kzalloc(n_pins * sizeof(*ptp->pin_dev_attr),
> + ptp->pin_dev_attr = kcalloc(n_pins, sizeof(*ptp->pin_dev_attr),
> GFP_KERNEL);
> if (!ptp->pin_dev_attr)
> goto no_dev_attr;
>
> - ptp->pin_attr = kzalloc((1 + n_pins) * sizeof(struct attribute *),
> - GFP_KERNEL);
> + ptp->pin_attr = kmalloc_array(1 + n_pins, sizeof(*ptp->pin_attr),
> + GFP_KERNEL);

I prefer kcalloc here as well, even if it isn't strictly necessary
according to the current usage of pin_attr. That way, any future
changes to the pin handling code won't have to worry about
uninitialized memory. After all, this is hardly a performance path.

> if (!ptp->pin_attr)
> goto no_pin_attr;
>
> @@ -289,6 +289,9 @@ static int ptp_populate_pins(struct ptp_clock *ptp)
> ptp->pin_attr[i] = &da->attr;
> }
>
> + /* NULL terminator */
> + ptp->pin_attr[n_pins] = NULL;

And drop this then, please.

Thanks,
Richard