Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756848Ab1CRPMT (ORCPT ); Fri, 18 Mar 2011 11:12:19 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:47157 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752724Ab1CRPMO (ORCPT ); Fri, 18 Mar 2011 11:12:14 -0400 Date: Fri, 18 Mar 2011 15:12:19 +0000 From: Alan Cox To: Cc: , , , , , Subject: Re: [PATCH] NFC: Driver for Inside Secure MicroRead NFC chip Message-ID: <20110318151219.7aedc765@lxorguk.ukuu.org.uk> In-Reply-To: <99B09243E1A5DA4898CDD8B7001114481085881963@EXMB04.eu.tieto.com> References: <1300444824-13713-1-git-send-email-waldemar.rymarkiewicz@tieto.com> <1300444824-13713-2-git-send-email-waldemar.rymarkiewicz@tieto.com> <20110318110348.728f6036@lxorguk.ukuu.org.uk> <99B09243E1A5DA4898CDD8B7001114481085881963@EXMB04.eu.tieto.com> X-Mailer: Claws Mail 3.7.8 (GTK+ 2.22.0; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 972 Lines: 34 > >Would it not be lighter to use atomic bit ops ? > > Do you mean in order to remove rx_mutex? > > mutex_lock(&info->rx_mutex); > atomic_set(info->irq_state ,1); > mutex_unlock(&info->rx_mutex); > > looks a bit strange. I still need the rx_mutex to protect irq_state while reading i2c. > > mutex_lock(&info->rx_mutex); > ret = i2c_master_recv(client, info->buf, info->buflen); > info->irq_state = 0; > mutex_unlock(&info->rx_mutex); > I was thinking clear_bit/test_and_set_bit rather than atomic_t operations. ie in the IRQ clear_bit(0, &info->irq_state); in the main path if (test_and_set_bit(0, &info->state)) i2c_master_recv(...) but if the mutex is needed anyway it doesn't help make the code saner. -- 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/