From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Axtens Subject: Re: [PATCH v4 29/32] cxlflash: Fix to double the delay each time Date: Tue, 29 Sep 2015 11:40:32 +1000 Message-ID: <87wpvat33j.fsf@gamma.ozlabs.ibm.com> References: <1443222593-8828-1-git-send-email-mrochs@linux.vnet.ibm.com> <1443223157-10039-1-git-send-email-mrochs@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: Received: from mail-pa0-f47.google.com ([209.85.220.47]:35940 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753712AbbI2Bkq convert rfc822-to-8bit (ORCPT ); Mon, 28 Sep 2015 21:40:46 -0400 Received: by pablk4 with SMTP id lk4so92961733pab.3 for ; Mon, 28 Sep 2015 18:40:46 -0700 (PDT) In-Reply-To: <1443223157-10039-1-git-send-email-mrochs@linux.vnet.ibm.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Matthew R. Ochs" , linux-scsi@vger.kernel.org, James Bottomley , "Nicholas A. Bellinger" , Brian King , Ian Munsie , Andrew Donnellan , Tomas Henzl , David Laight Cc: Michael Neuling , linuxppc-dev@lists.ozlabs.org, Manoj Kumar -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 "Matthew R. Ochs" writes: > From: Manoj Kumar > > The operator used to double the delay is incorrect and > does not result in delay doubling. > > To fix, use a left shift instead of the XOR operator. > I can see that the patch is correct, but this commit message is a bit confusing. What delay? In what circumstances are you doubling it? Why? Regards, Daniel > Reported-by: Tomas Henzl > Signed-off-by: Matthew R. Ochs > Signed-off-by: Manoj N. Kumar > Reviewed-by: Brian King > --- > drivers/scsi/cxlflash/main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c > index ab11ee6..be78906 100644 > --- a/drivers/scsi/cxlflash/main.c > +++ b/drivers/scsi/cxlflash/main.c > @@ -303,7 +303,7 @@ write_rrin: > if (rrin != 0x1) > break; > /* Double delay each time */ > - udelay(2 ^ nretry); > + udelay(2 << nretry); > } while (nretry++ < MC_ROOM_RETRY_CNT); > } > > -- > 2.1.0 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJWCewRAAoJEPC3R3P2I92F7xQQAKxvcnUpB/xLeq6CyB3LwsB/ cqFMP7OwDRfmQZG5ld5uqfXsjCCW4c0BaVknMgpD5gAdHbrwbc5gFgYuC0kIDUrH aEwTyXwaH7+o82agjxf7TRrsh2NtLzdSB6NN1UNL73aPVXJFKWITajIKUAnYF5d1 AvB3yb4KtX0qklo205igVceuLbBBaXY6Lz3V58XDSG2JAtVlVkamJK7M8zySrNTY Y627zTVkbopOGaBMLmu0q92dWDk2saU2wqKolo+pRy1NpOmY2XOU9hSRqCqAhnS4 xOWj7Bdrh1HdnQX26EC+f485nOijf0zddpJ6LsgPWMElJ04N4siQwmrwG55FbOs4 QDFKPdsVdZ8qmVueGCLRdTsMNAxcobi44P1/QXxGTmsn9xqyQBgZUzbd5oRUVswI md21qir3xjRN7g4R78084I88dM1yrHpJ6NuHDxFeXbtrw8087lKgU05Ys6m+ebuC 7nPnYRJ54frAi6a7mmBq+Xc4IbVnaGl9IZi1gujM2mkTaAk7/wl7oRMYyUTKlblp BeoQN0cdG1fChP1yLHzZV6G1JXwSw7nP6otf7YfUIrmjbzeZ5zWovSqJjnvNYBCT zgW681gIF3GwaN9z9I+XY9BO1P6EkYp+dgAQM7PqdR00GjFjTJO0yn8WHh113lmE L2sC0Nezuq8V4/qtspmh =Km/z -----END PGP SIGNATURE----- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-x230.google.com (mail-pa0-x230.google.com [IPv6:2607:f8b0:400e:c03::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 0A3271A05F2 for ; Tue, 29 Sep 2015 11:40:48 +1000 (AEST) Received: by pablk4 with SMTP id lk4so92961746pab.3 for ; Mon, 28 Sep 2015 18:40:46 -0700 (PDT) From: Daniel Axtens To: "Matthew R. Ochs" , linux-scsi@vger.kernel.org, James Bottomley , "Nicholas A. Bellinger" , Brian King , Ian Munsie , Andrew Donnellan , Tomas Henzl , David Laight Cc: Michael Neuling , linuxppc-dev@lists.ozlabs.org, Manoj Kumar Subject: Re: [PATCH v4 29/32] cxlflash: Fix to double the delay each time In-Reply-To: <1443223157-10039-1-git-send-email-mrochs@linux.vnet.ibm.com> References: <1443222593-8828-1-git-send-email-mrochs@linux.vnet.ibm.com> <1443223157-10039-1-git-send-email-mrochs@linux.vnet.ibm.com> Date: Tue, 29 Sep 2015 11:40:32 +1000 Message-ID: <87wpvat33j.fsf@gamma.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , =2D----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 "Matthew R. Ochs" writes: > From: Manoj Kumar > > The operator used to double the delay is incorrect and > does not result in delay doubling. > > To fix, use a left shift instead of the XOR operator. > I can see that the patch is correct, but this commit message is a bit confusing. What delay? In what circumstances are you doubling it? Why? Regards, Daniel > Reported-by: Tomas Henzl > Signed-off-by: Matthew R. Ochs > Signed-off-by: Manoj N. Kumar > Reviewed-by: Brian King > --- > drivers/scsi/cxlflash/main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c > index ab11ee6..be78906 100644 > --- a/drivers/scsi/cxlflash/main.c > +++ b/drivers/scsi/cxlflash/main.c > @@ -303,7 +303,7 @@ write_rrin: > if (rrin !=3D 0x1) > break; > /* Double delay each time */ > - udelay(2 ^ nretry); > + udelay(2 << nretry); > } while (nretry++ < MC_ROOM_RETRY_CNT); > } >=20=20 > --=20 > 2.1.0 =2D----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJWCewRAAoJEPC3R3P2I92F7xQQAKxvcnUpB/xLeq6CyB3LwsB/ cqFMP7OwDRfmQZG5ld5uqfXsjCCW4c0BaVknMgpD5gAdHbrwbc5gFgYuC0kIDUrH aEwTyXwaH7+o82agjxf7TRrsh2NtLzdSB6NN1UNL73aPVXJFKWITajIKUAnYF5d1 AvB3yb4KtX0qklo205igVceuLbBBaXY6Lz3V58XDSG2JAtVlVkamJK7M8zySrNTY Y627zTVkbopOGaBMLmu0q92dWDk2saU2wqKolo+pRy1NpOmY2XOU9hSRqCqAhnS4 xOWj7Bdrh1HdnQX26EC+f485nOijf0zddpJ6LsgPWMElJ04N4siQwmrwG55FbOs4 QDFKPdsVdZ8qmVueGCLRdTsMNAxcobi44P1/QXxGTmsn9xqyQBgZUzbd5oRUVswI md21qir3xjRN7g4R78084I88dM1yrHpJ6NuHDxFeXbtrw8087lKgU05Ys6m+ebuC 7nPnYRJ54frAi6a7mmBq+Xc4IbVnaGl9IZi1gujM2mkTaAk7/wl7oRMYyUTKlblp BeoQN0cdG1fChP1yLHzZV6G1JXwSw7nP6otf7YfUIrmjbzeZ5zWovSqJjnvNYBCT zgW681gIF3GwaN9z9I+XY9BO1P6EkYp+dgAQM7PqdR00GjFjTJO0yn8WHh113lmE L2sC0Nezuq8V4/qtspmh =3DKm/z =2D----END PGP SIGNATURE-----