Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752549AbaFPMkM (ORCPT ); Mon, 16 Jun 2014 08:40:12 -0400 Received: from mail-qa0-f46.google.com ([209.85.216.46]:45557 "EHLO mail-qa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751249AbaFPMkL (ORCPT ); Mon, 16 Jun 2014 08:40:11 -0400 MIME-Version: 1.0 In-Reply-To: <539EB43B.8070707@realsil.com.cn> References: <7b58fb0b0915ea0b0838404c74ec22a3b6e5f5a8.1402037565.git.micky_ching@realsil.com.cn> <539EB43B.8070707@realsil.com.cn> Date: Mon, 16 Jun 2014 14:40:09 +0200 Message-ID: Subject: Re: [PATCH 2/2] mmc: rtsx: add support for async request From: Ulf Hansson To: micky Cc: Samuel Ortiz , Lee Jones , Chris Ball , devel@linuxdriverproject.org, "linux-kernel@vger.kernel.org" , linux-mmc , Greg Kroah-Hartman , Dan Carpenter , Roger , Wei WANG Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16 June 2014 11:09, micky wrote: > On 06/16/2014 04:42 PM, Ulf Hansson wrote: >>> >>> @@ -36,7 +37,10 @@ struct realtek_pci_sdmmc { >>> > struct rtsx_pcr *pcr; >>> > struct mmc_host *mmc; >>> > struct mmc_request *mrq; >>> >+ struct workqueue_struct *workq; >>> >+#define SDMMC_WORKQ_NAME "rtsx_pci_sdmmc_workq" >>> > >>> >+ struct work_struct work; >> >> I am trying to understand why you need a work/workqueue to implement >> this feature. Is that really the case? >> >> Could you elaborate on the reasons? > > Hi Uffe, > > we need return as fast as possible in mmc_host_ops request(ops->request) > callback, > so the mmc core can continue handle next request. > when next request everything is ready, it will wait previous done(if not > done), > then call ops->request(). > > we can't use atomic context, because we use mutex_lock() to protect ops->request should never executed in atomic context. Is that your concern? > resource, and we have to hold the lock during handle request. > So I use workq, we just queue a work and return in ops->request(), > The mmc core can continue without blocking at ops->request(). > > Best Regards. > micky. Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/