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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 1E3A7C43215 for ; Sat, 16 Nov 2019 15:52:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEB0520857 for ; Sat, 16 Nov 2019 15:52:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919560; bh=dvvlDb/+0VMhtBKkl1moFhh/et82E8jtpyGoaFbPt7I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=s2Hr+3b9nGRRps44YjRWunLEm5oupzT6kNHOBr+nDZjR3okq4LygwMwwAi2IaXFTF sDOYMDvcgLaeAkNOw7wSQuCiO9QKLDyP91DfD3vWaDbojZSLbknQKFPG8xcnffkkz0 bOiBtCYROEskPYL1XgbckMZXGwJcf0BPNcFi8WAM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731057AbfKPPw3 (ORCPT ); Sat, 16 Nov 2019 10:52:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:33142 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731007AbfKPPwV (ORCPT ); Sat, 16 Nov 2019 10:52:21 -0500 Received: from sasha-vm.mshome.net (unknown [50.234.116.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 42E9020728; Sat, 16 Nov 2019 15:52:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919541; bh=dvvlDb/+0VMhtBKkl1moFhh/et82E8jtpyGoaFbPt7I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=O7dVi7VI6xUFGv7gJYMn0cvHgj6rKot0LCfaaEfKKpAAEDSOYNdtrHN4ufrI6mITe dMDiIlt0g8iRoEfZ4TmAHjN5MlZKwDCr4m++3H+0qHK6rLJw+2xLr8hWudVSP0CO/P I1QmPk7cu79HQHcFJqBDgnqD5FXHVTF70zdM9xSo= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Anton Ivanov , Richard Weinberger , Sasha Levin , linux-um@lists.infradead.org Subject: [PATCH AUTOSEL 4.9 56/99] um: Make line/tty semantics use true write IRQ Date: Sat, 16 Nov 2019 10:50:19 -0500 Message-Id: <20191116155103.10971-56-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116155103.10971-1-sashal@kernel.org> References: <20191116155103.10971-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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