From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753916Ab2ATPlk (ORCPT ); Fri, 20 Jan 2012 10:41:40 -0500 Received: from g1t0029.austin.hp.com ([15.216.28.36]:34319 "EHLO g1t0029.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753441Ab2ATPlj (ORCPT ); Fri, 20 Jan 2012 10:41:39 -0500 Date: Fri, 20 Jan 2012 09:41:36 -0600 From: scameron@beardog.cce.hp.com To: Akinobu Mita Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, iss_storagedev@hp.com, "James E.J. Bottomley" , linux-scsi@vger.kernel.org, scameron@beardog.cce.hp.com Subject: Re: [PATCH] hpsa: use find_first_zero_bit Message-ID: <20120120154136.GH21002@beardog.cce.hp.com> References: <1327072528-8479-1-git-send-email-akinobu.mita@gmail.com> <1327072528-8479-5-git-send-email-akinobu.mita@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1327072528-8479-5-git-send-email-akinobu.mita@gmail.com> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 21, 2012 at 12:15:27AM +0900, Akinobu Mita wrote: > Use find_first_zero_bit to find the first cleared bit in a memory region. > > This also includes the following minor changes. > - Use bitmap_zero > - Reduce unnecessary atomic bitops usage Ack. This isn't performance sensitive code though, hpsa_find_target_lun() only gets called during device discovery when a multi-lun device like a tape drive with an auto changer is encountered. I tried it out and it doesn't conflict with any of the patches I sent up yesterday, and it works with a tape drive/autochanger. -- steve > > Signed-off-by: Akinobu Mita > Cc: "Stephen M. Cameron" > Cc: iss_storagedev@hp.com > Cc: "James E.J. Bottomley" > Cc: linux-scsi@vger.kernel.org > --- > drivers/scsi/hpsa.c | 18 ++++++++---------- > 1 files changed, 8 insertions(+), 10 deletions(-) > > diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c > index 7d14443..7f79ed8 100644 > --- a/drivers/scsi/hpsa.c > +++ b/drivers/scsi/hpsa.c > @@ -577,21 +577,19 @@ static int hpsa_find_target_lun(struct ctlr_info *h, > int i, found = 0; > DECLARE_BITMAP(lun_taken, HPSA_MAX_DEVICES); > > - memset(&lun_taken[0], 0, HPSA_MAX_DEVICES >> 3); > + bitmap_zero(lun_taken, HPSA_MAX_DEVICES); > > for (i = 0; i < h->ndevices; i++) { > if (h->dev[i]->bus == bus && h->dev[i]->target != -1) > - set_bit(h->dev[i]->target, lun_taken); > + __set_bit(h->dev[i]->target, lun_taken); > } > > - for (i = 0; i < HPSA_MAX_DEVICES; i++) { > - if (!test_bit(i, lun_taken)) { > - /* *bus = 1; */ > - *target = i; > - *lun = 0; > - found = 1; > - break; > - } > + i = find_first_zero_bit(lun_taken, HPSA_MAX_DEVICES); > + if (i < HPSA_MAX_DEVICES) { > + /* *bus = 1; */ > + *target = i; > + *lun = 0; > + found = 1; > } > return !found; > } > -- > 1.7.4.4