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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 51C5CC432C3 for ; Wed, 27 Nov 2019 20:52:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 26A43218AE for ; Wed, 27 Nov 2019 20:52:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574887922; bh=PZrL9vWqCTiFw2xV4xCtIutuGc0aIhE7zE1PDg4v3/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=HuPCobdTqm0mn+EcN4Oay9p0UcqCiyCCeRRtxKvAKW/ew+i7ALYBVQboNVXk9k8HH JhEmfc0XC8bLlMH3AXqfFbuenCwbzBlgQiMWqV/v6+XNuoMHZ6QAG3jGwoiv/PT3O2 ihl3y6khqCswIDM5AqXUbuPVbrKcwHiA4akUaP4M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730554AbfK0Uv4 (ORCPT ); Wed, 27 Nov 2019 15:51:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:38936 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730539AbfK0Uvv (ORCPT ); Wed, 27 Nov 2019 15:51:51 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 A505321774; Wed, 27 Nov 2019 20:51:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574887911; bh=PZrL9vWqCTiFw2xV4xCtIutuGc0aIhE7zE1PDg4v3/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D14F89c3dRxUY2VhtqoLKBeAkspsTXjUpK4sqGnSe1z0O5EtXu5hMiJ6AtTxxYZjF 68bjPvMafcnneXaGUjQkLghB5YOqA+IBYtn0euG0u33mfxbMOmY0q1kX2zKhQaeghv zllRKnDsVhK+bP26+Q6tq2eHbVbi21jw4VvdRr/4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Anton Ivanov , Richard Weinberger , Sasha Levin Subject: [PATCH 4.14 101/211] um: Make line/tty semantics use true write IRQ Date: Wed, 27 Nov 2019 21:30:34 +0100 Message-Id: <20191127203103.224107150@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191127203049.431810767@linuxfoundation.org> References: <20191127203049.431810767@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: Anton Ivanov [ Upstream commit 917e2fd2c53eb3c4162f5397555cbd394390d4bc ] This fixes a long standing bug where large amounts of output could freeze the tty (most commonly seen on stdio console). While the bug has always been there it became more pronounced after moving to the new interrupt controller. The line semantics are now changed to have true IRQ write semantics which should further improve the tty/line subsystem stability and performance Signed-off-by: Anton Ivanov Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- arch/um/drivers/line.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index 366e57f5e8d63..7e524efed5848 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -261,7 +261,7 @@ static irqreturn_t line_write_interrupt(int irq, void *data) if (err == 0) { spin_unlock(&line->lock); return IRQ_NONE; - } else if (err < 0) { + } else if ((err < 0) && (err != -EAGAIN)) { line->head = line->buffer; line->tail = line->buffer; } -- 2.20.1