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=unavailable 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 67AF7C43215 for ; Wed, 27 Nov 2019 20:44:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 40C0F21775 for ; Wed, 27 Nov 2019 20:44:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574887450; bh=dvvlDb/+0VMhtBKkl1moFhh/et82E8jtpyGoaFbPt7I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ydZJZ68DL+dTCoMGvRJZWseBhx5JCc1oLqQ1jQ07OBbCpTNt92flPtAx7VLtLwmjw k3+28eXILnWHvk3gN2jmMT5gsBI8ygx0mS59XuZZfEEd+5z3AUQD91wrD2EMtA4utl QamRmiGrsvGTPESC4XbrZ45F1iqac1oEQLLD+1Yw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729551AbfK0UoJ (ORCPT ); Wed, 27 Nov 2019 15:44:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:52484 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729498AbfK0Un4 (ORCPT ); Wed, 27 Nov 2019 15:43:56 -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 D25A8215F1; Wed, 27 Nov 2019 20:43:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574887436; bh=dvvlDb/+0VMhtBKkl1moFhh/et82E8jtpyGoaFbPt7I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Sv+AABA5WXqkpQRdq3kJjm/G2+h+/fZ1pRP03VQORV2UNUJ8EcIhxD8pXb+L1lpno FmahgONuzW99v2VToH7CDCCwP2PExMhHMi/7+NA8hvqJxOf14GUaq1UGhAYe9RlnTe GfEnKyLwMEKGDOOlNru1+9DDWZa5e/IB8Gj+lSPM= 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 4.9 068/151] um: Make line/tty semantics use true write IRQ Date: Wed, 27 Nov 2019 21:30:51 +0100 Message-Id: <20191127203034.236462217@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191127203000.773542911@linuxfoundation.org> References: <20191127203000.773542911@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 62087028a9ce1..d2ad45c101137 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -260,7 +260,7 @@ 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