From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Subject: Re: [PATCH 2/4] tty: serial: 8250: add optional spinlock arg to serial8250_rx_chars Date: Fri, 22 Jan 2016 08:18:53 -0800 Message-ID: <56A2566D.6010408@hurleysoftware.com> References: <877fj1rjs0.fsf@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <877fj1rjs0.fsf@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org To: John Ogness , gregkh@linuxfoundation.org Cc: vinod.koul@intel.com, dan.j.williams@intel.com, bigeasy@linutronix.de, tony@atomide.com, nsekhar@ti.com, peter.ujfalusi@ti.com, dmaengine@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-serial@vger.kernel.org Hi John, On 01/22/2016 02:27 AM, John Ogness wrote: > serial8250_rx_chars() must be called from interrupt context and with > the port lock held. The port lock is released temporarily within that > function to call tty_flip_buffer_push(). However, there may be other > drivers that need to synchronize the tty_flip_buffer_push() call within > serial8250_rx_chars() with other contexts. Since the port lock cannot > be used for this synchronization, an optional spinlock argument is added. > If non-NULL, this will be locked during the tty_flip_buffer_push() call. I removed the port lock drop-claim in serial8250_rx_chars in patch "serial: 8250: Remove low_latency workaround" (Greg has this patch in his inbox but not in next because of the merge window). IOW, you can drop this patch. Regards, Peter Hurley