Re: bluetooth drivers : kmalloc to kzalloc conversion

From: Om Narasimhan
Date: Sun Sep 17 2006 - 22:41:21 EST


On 9/17/06, Dmitry Torokhov <dtor@xxxxxxxxxxxxx> wrote:
On Sunday 17 September 2006 20:54, Om Narasimhan wrote:
> --- a/drivers/bluetooth/hci_usb.c
> +++ b/drivers/bluetooth/hci_usb.c
> @@ -147,10 +147,9 @@ static struct usb_device_id blacklist_id
>
> static struct _urb *_urb_alloc(int isoc, gfp_t gfp)
> {
> -struct _urb *_urb = kmalloc(sizeof(struct _urb) +
> +struct _urb *_urb = kzalloc(sizeof(struct _urb) +
> sizeof(struct usb_iso_packet_descriptor) * isoc, gfp);
> if (_urb) {
> -memset(_urb, 0, sizeof(*_urb));
> usb_init_urb(&_urb->urb);
> }
> return _urb;
>

Note that only beginning if the aloocated memory was zeroed in original
code; your patch may introduce slowdowns.
Would it? I thought memset() uses block move operation which doesn't
scale linearly.
And, usb_init_urb() calls memset() anyway, so the previously existed
memset() was superfluous.

Thanks for the comment.
Regards,
Om.
-
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