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 C37E5C432C3 for ; Sat, 16 Nov 2019 16:20:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99D5521479 for ; Sat, 16 Nov 2019 16:20:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573921229; bh=DYDeOGRcI4kuQWrRA6hmaepxNa+IRLppnQKcvt38DBs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=h2uQuKQyuu05g4xNYwHGPRFgryCeFLsVk+BP+ZJuZjwFC85rvlAy/CyybFze2l10n 8MUZK5Pz5IY1SiCS+3a9wggPjHPXhu3DIvJX0KVChWdaEoG8t+qWrADxWYrLOUEhBa m/kWYV1QQU5xGtD9/JZI2V0vEDjG+pgIElAtS5eo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728992AbfKPPob (ORCPT ); Sat, 16 Nov 2019 10:44:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:49344 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727880AbfKPPo3 (ORCPT ); Sat, 16 Nov 2019 10:44:29 -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 4F52020803; Sat, 16 Nov 2019 15:44:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919068; bh=DYDeOGRcI4kuQWrRA6hmaepxNa+IRLppnQKcvt38DBs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i2TsweSq3Q7NI+TkM2IrnEvvf6i4gWnfpimWLbLTZZ3uVSwfe8yRDoQy6TCMS0opo y/h6DXcMF2/wXSEHUKLnEH3X0ONxRv8BedLNDd1GGV4d4vv99fgqom0WuSBAMh+NO9 T2oSO4UvnLNGKq40MePp9C6nosrY0Kx8qd0a47is= 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 4.19 140/237] um: Make line/tty semantics use true write IRQ Date: Sat, 16 Nov 2019 10:39:35 -0500 Message-Id: <20191116154113.7417-140-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116154113.7417-1-sashal@kernel.org> References: <20191116154113.7417-1-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 | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index 8d80b27502e6a..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; } @@ -284,7 +284,7 @@ int line_setup_irq(int fd, int input, int output, struct line *line, void *data) if (err) return err; if (output) - err = um_request_irq(driver->write_irq, fd, IRQ_NONE, + err = um_request_irq(driver->write_irq, fd, IRQ_WRITE, line_write_interrupt, IRQF_SHARED, driver->write_irq_name, data); return err; -- 2.20.1