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Re: [Qemu-trivial] [PATCH 2/3] xhci: remove unused code
From: |
Michael Tokarev |
Subject: |
Re: [Qemu-trivial] [PATCH 2/3] xhci: remove unused code |
Date: |
Wed, 29 Apr 2015 09:48:51 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.6.0 |
28.04.2015 12:11, address@hidden wrote:
> From: Gonglei <address@hidden>
>
> Value from xfer->packet.ep is assigned to ep here, but that
> stored value is not used before it is overwritten. Remove it.
>
> Cc: Gerd Hoffmann <address@hidden>
> Signed-off-by: Gonglei <address@hidden>
> ---
> hw/usb/hcd-xhci.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
> index ba15ae0..99f11fc 100644
> --- a/hw/usb/hcd-xhci.c
> +++ b/hw/usb/hcd-xhci.c
> @@ -2204,7 +2204,6 @@ static void xhci_kick_ep(XHCIState *xhci, unsigned int
> slotid,
> if (epid == 1) {
> if (xhci_fire_ctl_transfer(xhci, xfer) >= 0) {
> epctx->next_xfer = (epctx->next_xfer + 1) % TD_QUEUE;
> - ep = xfer->packet.ep;
> } else {
> DPRINTF("xhci: error firing CTL transfer\n");
> }
This one is somewhat fun. ep variable is not used in whole this
function until the very end, with the code:
ep = xhci_epid_to_usbep(xhci, slotid, epid);
if (ep) {
usb_device_flush_ep_queue(ep->dev, ep);
}
There are only 2 assignments to it here, it is the NULL
initializer and this place which is being removed by this
patch (which is obviously unused).
So, I think if we were to drop this assignment, we should
remove the initializer too. But before doing this, I think
we should try to remember _why_ this assignment is here in
the first place. The code looks like after the loop, this
ep variable was supposed to be used for something. Or is
it just a leftover from 518ad5f2a075 (Cc'ing the author)?
I haven't looked at all this in more details without good
knowlege of the protocol and background.
Thanks,
/mjt