From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932211AbdBET3v (ORCPT + 2 others); Sun, 5 Feb 2017 14:29:51 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:28575 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932195AbdBET3t (ORCPT ); Sun, 5 Feb 2017 14:29:49 -0500 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Felipe Balbi , Willy Tarreau Subject: [PATCH 3.10 121/319] usb: gadget: u_ether: remove interrupt throttling Date: Sun, 5 Feb 2017 20:19:03 +0100 Message-Id: <1486322541-8206-22-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1486322541-8206-1-git-send-email-w@1wt.eu> References: <1486322541-8206-1-git-send-email-w@1wt.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=latin1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Felipe Balbi 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: Willy Tarreau --- drivers/usb/gadget/u_ether.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/drivers/usb/gadget/u_ether.c b/drivers/usb/gadget/u_ether.c index aad066d..ef5c623 100644 --- a/drivers/usb/gadget/u_ether.c +++ b/drivers/usb/gadget/u_ether.c @@ -584,14 +584,6 @@ 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) % qmult) != 0) - : 0; - retval = usb_ep_queue(in, req, GFP_ATOMIC); switch (retval) { default: -- 2.8.0.rc2.1.gbe9624a