From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: Re: [PATCH] scsi: sr.c use unaligned access helpers Date: Tue, 07 Oct 2008 14:19:14 +0200 Message-ID: <48EB53C2.6050101@panasas.com> References: <1223081173.6778.4.camel@brick> <20081007121025.GY19428@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from gw-ca.panasas.com ([66.104.249.162]:10753 "EHLO laguna.int.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752718AbYJGMTT (ORCPT ); Tue, 7 Oct 2008 08:19:19 -0400 In-Reply-To: <20081007121025.GY19428@kernel.dk> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jens Axboe Cc: Harvey Harrison , James Bottomley , Andrew Morton , linux-scsi Jens Axboe wrote: > On Fri, Oct 03 2008, Harvey Harrison wrote: >> Preserve the cd->capacity indentation near the #if 0'd if() statement. >> >> Signed-off-by: Harvey Harrison >> --- >> drivers/scsi/sr.c | 26 ++++++++------------------ >> 1 files changed, 8 insertions(+), 18 deletions(-) >> >> diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c >> index 27f5bfd..f1b650e 100644 >> --- a/drivers/scsi/sr.c >> +++ b/drivers/scsi/sr.c >> @@ -45,6 +45,7 @@ >> #include >> #include >> #include >> +#include >> >> #include >> #include >> @@ -280,10 +281,7 @@ static int sr_done(struct scsi_cmnd *SCpnt) >> case ILLEGAL_REQUEST: >> if (!(SCpnt->sense_buffer[0] & 0x90)) >> break; >> - error_sector = (SCpnt->sense_buffer[3] << 24) | >> - (SCpnt->sense_buffer[4] << 16) | >> - (SCpnt->sense_buffer[5] << 8) | >> - SCpnt->sense_buffer[6]; >> + error_sector = get_unaligned_be32(SCpnt->sense_buffer + 3); >> if (SCpnt->request->bio != NULL) >> block_sectors = >> bio_sectors(SCpnt->request->bio); >> @@ -445,13 +443,9 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq) >> SCpnt->sdb.length = this_count * s_size; >> } >> >> - SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff; >> - SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff; >> - SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff; >> - SCpnt->cmnd[5] = (unsigned char) block & 0xff; >> + put_unaligned_be32(block, SCpnt->cmnd + 2); >> SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0; >> - SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff; >> - SCpnt->cmnd[8] = (unsigned char) this_count & 0xff; >> + put_unaligned_be16(this_count, SCpnt->cmnd + 7); >> >> /* >> * We shouldn't disconnect in the middle of a sector, so with a dumb > > Lets not please, it reduces readability a lot when you are used to SCSI > cdb filling. > > I feel the opposite. That is: put_unaligned_be32(block, SCpnt->cmnd + 2); is much more readable for me. Coming from the spec, I'm looking for a __b32 at offset CDB+2 and not: "SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;" At offset CDB+4 the 2nd-or-3rd? order byte of "block". And for BE systems it's a gain. So please DO My $0.017 Boaz