From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E211ACA9EC9 for ; Mon, 4 Nov 2019 22:02:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B1FC9217F4 for ; Mon, 4 Nov 2019 22:02:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572904947; bh=jMAEKlxyC3ermhSxITfVSGgBVe4mb/AT5OiGWW7wYCw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IYpUwAd00nM+asQ7+foYeiQW9kNaVsoqpLFdNHNfFN/KHzXRgl4kUCvc07tRu1Qbb /Nmc/UUQyIzwI9dDskEYq2XWZIYov8HqxefhoVyjaCKzToA3XmZnBFOwErkCgYiiOa gJXtgbnbE4nggcGrxjv36TDkIza6NucpmHUXb2UM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389301AbfKDWC0 (ORCPT ); Mon, 4 Nov 2019 17:02:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:60180 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389120AbfKDWB4 (ORCPT ); Mon, 4 Nov 2019 17:01:56 -0500 Received: from localhost (6.204-14-84.ripe.coltfrance.com [84.14.204.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C469F20650; Mon, 4 Nov 2019 22:01:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572904915; bh=jMAEKlxyC3ermhSxITfVSGgBVe4mb/AT5OiGWW7wYCw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GTcSu2B324WH+JOpYT12V8xoKwjBIVkT9z+5syfn0FaJkfaKy+K+l7lRh2zxUY3dS rOPHKnjqXMY0mL6shLfpL/xTLdCwwTyFVmnHDgT6FxUJY86mwcyDn/p4eWjK7fcO1i pllWitW/jmRmkZMteJ6Dk8VVpeFkUR6ICh3IygAY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , Oliver Neukum , Christoph Hellwig Subject: [PATCH 4.19 114/149] UAS: Revert commit 3ae62a42090f ("UAS: fix alignment of scatter/gather segments") Date: Mon, 4 Nov 2019 22:45:07 +0100 Message-Id: <20191104212144.343422897@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191104212126.090054740@linuxfoundation.org> References: <20191104212126.090054740@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alan Stern commit 1186f86a71130a7635a20843e355bb880c7349b2 upstream. Commit 3ae62a42090f ("UAS: fix alignment of scatter/gather segments"), copying a similar commit for usb-storage, attempted to solve a problem involving scatter-gather I/O and USB/IP by setting the virt_boundary_mask for mass-storage devices. However, it now turns out that the analogous change in usb-storage interacted badly with commit 09324d32d2a0 ("block: force an unlimited segment size on queues with a virt boundary"), which was added later. A typical error message is: ehci-pci 0000:00:13.2: swiotlb buffer is full (sz: 327680 bytes), total 32768 (slots), used 97 (slots) There is no longer any reason to keep the virt_boundary_mask setting in the uas driver. It was needed in the first place only for handling devices with a block size smaller than the maxpacket size and where the host controller was not capable of fully general scatter-gather operation (that is, able to merge two SG segments into a single USB packet). But: High-speed or slower connections never use a bulk maxpacket value larger than 512; The SCSI layer does not handle block devices with a block size smaller than 512 bytes; All the host controllers capable of SuperSpeed operation can handle fully general SG; Since commit ea44d190764b ("usbip: Implement SG support to vhci-hcd and stub driver") was merged, the USB/IP driver can also handle SG. Therefore all supported device/controller combinations should be okay with no need for any special virt_boundary_mask. So in order to head off potential problems similar to those affecting usb-storage, this patch reverts commit 3ae62a42090f. Signed-off-by: Alan Stern CC: Oliver Neukum CC: Acked-by: Christoph Hellwig Fixes: 3ae62a42090f ("UAS: fix alignment of scatter/gather segments") Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.1910231132470.1878-100000@iolanthe.rowland.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/storage/uas.c | 20 -------------------- 1 file changed, 20 deletions(-) --- a/drivers/usb/storage/uas.c +++ b/drivers/usb/storage/uas.c @@ -796,30 +796,10 @@ static int uas_slave_alloc(struct scsi_d { struct uas_dev_info *devinfo = (struct uas_dev_info *)sdev->host->hostdata; - int maxp; sdev->hostdata = devinfo; /* - * We have two requirements here. We must satisfy the requirements - * of the physical HC and the demands of the protocol, as we - * definitely want no additional memory allocation in this path - * ruling out using bounce buffers. - * - * For a transmission on USB to continue we must never send - * a package that is smaller than maxpacket. Hence the length of each - * scatterlist element except the last must be divisible by the - * Bulk maxpacket value. - * If the HC does not ensure that through SG, - * the upper layer must do that. We must assume nothing - * about the capabilities off the HC, so we use the most - * pessimistic requirement. - */ - - maxp = usb_maxpacket(devinfo->udev, devinfo->data_in_pipe, 0); - blk_queue_virt_boundary(sdev->request_queue, maxp - 1); - - /* * The protocol has no requirements on alignment in the strict sense. * Controllers may or may not have alignment restrictions. * As this is not exported, we use an extremely conservative guess.