Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757422Ab0KJX2N (ORCPT ); Wed, 10 Nov 2010 18:28:13 -0500 Received: from mail-vw0-f46.google.com ([209.85.212.46]:45492 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757010Ab0KJX2L (ORCPT ); Wed, 10 Nov 2010 18:28:11 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=MSdoPs3EQrUg+ulNPv9lWb/8fo1b6x7fNo4bPz3O3zEZ33HR2wtTtvYcDMJDtnL1yx jijzKo9Z/8r2tJyNuSQFtT2MZ4bryuY1Lwfiw8g+PAbxy1QSd4ZA4YYNeBIQCsrxPSXJ E4H46Qtpp37r8GYGG+41t8bGqCpBR4JAnM7yU= Message-ID: <4CDB2A81.5030100@garzik.org> Date: Wed, 10 Nov 2010 18:28:01 -0500 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.12) Gecko/20101027 Fedora/3.1.6-1.fc13 Thunderbird/3.1.6 MIME-Version: 1.0 To: James Bottomley CC: linux-scsi , James Bottomley , LKML Subject: Re: Patch added to scsi-rc-fixes-2.6: [SCSI] host lock push-down References: <201011102240.oAAMe86a001486@hera.kernel.org> In-Reply-To: <201011102240.oAAMe86a001486@hera.kernel.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1809 Lines: 43 On 11/10/2010 05:40 PM, James Bottomley wrote: > Your commit: > > [SCSI] host lock push-down > > Move the mid-layer's ->queuecommand() invocation from being locked > with the host lock to being unlocked to facilitate speeding up the > critical path for drivers who don't need this lock taken anyway. > > The patch below presents a simple SCSI host lock push-down as an > equivalent transformation. No locking or other behavior should change > with this patch. All existing bugs and locking orders are preserved. > > Minimal code disturbance was attempted with this change. Most drivers > needed only two one-line modifications for their host lock push-down. > > Signed-off-by: Jeff Garzik > Signed-off-by: James Bottomley > > has been added to the upstream SCSI tree > You can find it here: No comments on renaming ->queuecommand to something else? The consequences are rather dire if this goes unnoticed, yes? Jeff In http://marc.info/?l=linux-ide&m=128891665713984&w=2 I wrote: > An alternate arrangement, not presented by this patch, might > be preferred: in order to make it clear that queuecommand > locking has changed, one could s/queuecommand/queuecommand_nl/ in > Scsi_Host_Template, in order to guarantee that drivers are either > (a) upgraded or (b) broken at compile time. Compile-time detection of > new locking may be desirable, and I'll volunteer to change my patch to > do that, if community members prefer that route instead of below. -- 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/