From patchwork Wed Apr 21 09:55:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 426117 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 994D7C4363E for ; Wed, 21 Apr 2021 09:55:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6680C6143D for ; Wed, 21 Apr 2021 09:55:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238791AbhDUJ4U (ORCPT ); Wed, 21 Apr 2021 05:56:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:52444 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238651AbhDUJ4K (ORCPT ); Wed, 21 Apr 2021 05:56:10 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5DD9A61461; Wed, 21 Apr 2021 09:55:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618998937; bh=SK9ZenkpY1lkk5Kanf0WI01JeFJUJ3TcM9Wfil0ofYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xsig+VeM6WlC47I1hWI9BUuIoJI0/zMnvSTvn90rMOi8Lrqry1pPJa/5oGcc+buC0 jzZIbQYo0fPHksIZYB/jxDKjXb0rfpKWZ7tFSvFV5+Bax+qk50R29dyZnYBarhV1Jo EYWzcEscQxe79WlL/rXOqHKT1FWnnP85vg2jDOLMekz9fWE380FrAgZLZkqIXfyWNp xvdvZXL7g4zhQuW1cWA0w8Aqw02FOcBDzmz8buMF52JDWgfJeKYAbXrsrzq2I7lML5 407YLQkkGbZ6N7XpnW6TBRczYJ+CJWY2CYJZ4CHhZMZb7T9nxv4jjEOcHAivs8riiR oYOxm5HursiuQ== Received: from johan by xi.lan with local (Exim 4.93.0.4) (envelope-from ) id 1lZ9a8-0000pR-KF; Wed, 21 Apr 2021 11:55:40 +0200 From: Johan Hovold To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , "David S. Miller" Subject: [PATCH 23/26] serial: sunsu: drop low-latency workaround Date: Wed, 21 Apr 2021 11:55:06 +0200 Message-Id: <20210421095509.3024-24-johan@kernel.org> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20210421095509.3024-1-johan@kernel.org> References: <20210421095509.3024-1-johan@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org The sunsu driver has been carrying a workaround for the infamous low_latency behaviour of tty_flip_buffer_push() by dropping and reacquiring the port lock in the interrupt handler since 2004. Since commit a9c3f68f3cd8 ("tty: Fix low_latency BUG"), tty_flip_buffer_push() always schedules a work item to push data to the line discipline and there's no need to keep any low_latency hacks around. Cc: "David S. Miller" Signed-off-by: Johan Hovold --- drivers/tty/serial/sunsu.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/tty/serial/sunsu.c b/drivers/tty/serial/sunsu.c index 319e5ceb6130..12c2468f2b0e 100644 --- a/drivers/tty/serial/sunsu.c +++ b/drivers/tty/serial/sunsu.c @@ -466,12 +466,8 @@ static irqreturn_t sunsu_serial_interrupt(int irq, void *dev_id) if (status & UART_LSR_THRE) transmit_chars(up); - spin_unlock_irqrestore(&up->port.lock, flags); - tty_flip_buffer_push(&up->port.state->port); - spin_lock_irqsave(&up->port.lock, flags); - } while (!(serial_in(up, UART_IIR) & UART_IIR_NO_INT)); spin_unlock_irqrestore(&up->port.lock, flags);