From: Felipe Balbi Date: Tue, 1 Nov 2016 11:20:22 +0000 (+0200) Subject: usb: gadget: u_ether: remove interrupt throttling X-Git-Tag: v4.8.9~63 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=31da266e4b9a517dd4f4b127a44bdd7237e7efcf;p=thirdparty%2Fkernel%2Fstable.git usb: gadget: u_ether: remove interrupt throttling commit fd9afd3cbe404998d732be6cc798f749597c5114 upstream. According to Dave Miller "the networking stack has a hard requirement that all SKBs which are transmitted must have their completion signalled in a fininte amount of time. This is because, until the SKB is freed by the driver, it holds onto socket, netfilter, and other subsystem resources." In summary, this means that using TX IRQ throttling for the networking gadgets is, at least, complex and we should avoid it for the time being. Reported-by: Ville Syrjälä Tested-by: Ville Syrjälä Suggested-by: David Miller Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c index 9b9e71f2c66e3..f590adaaba8eb 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -585,14 +585,6 @@ static netdev_tx_t eth_start_xmit(struct sk_buff *skb, req->length = length; - /* throttle high/super speed IRQ rate back slightly */ - if (gadget_is_dualspeed(dev->gadget)) - req->no_interrupt = (((dev->gadget->speed == USB_SPEED_HIGH || - dev->gadget->speed == USB_SPEED_SUPER)) && - !list_empty(&dev->tx_reqs)) - ? ((atomic_read(&dev->tx_qlen) % dev->qmult) != 0) - : 0; - retval = usb_ep_queue(in, req, GFP_ATOMIC); switch (retval) { default: