From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753262AbeDJMdU (ORCPT ); Tue, 10 Apr 2018 08:33:20 -0400 Received: from mga18.intel.com ([134.134.136.126]:23314 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753203AbeDJMdO (ORCPT ); Tue, 10 Apr 2018 08:33:14 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,432,1517904000"; d="scan'208";a="32244242" Message-ID: <4984305eae452b7a72b8a13aa20cecec420df580.camel@linux.intel.com> Subject: Re: [PATCH] tpm: tpm_crb: relinquish locality on error path. From: Jarkko Sakkinen To: "Winkler, Tomas" , Jason Gunthorpe Cc: "Usyskin, Alexander" , "linux-integrity@vger.kernel.org" , "linux-security-module@vger.kernel.org" , "linux-kernel@vger.kernel.org" Date: Tue, 10 Apr 2018 15:33:08 +0300 In-Reply-To: <5B8DA87D05A7694D9FA63FD143655C1B94252660@hasmsx108.ger.corp.intel.com> References: <20180407161236.22969-1-tomas.winkler@intel.com> <5B8DA87D05A7694D9FA63FD143655C1B94252660@hasmsx108.ger.corp.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.0-4 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2018-04-10 at 09:00 +0000, Winkler, Tomas wrote: > > > > On Sat, 2018-04-07 at 19:12 +0300, Tomas Winkler wrote: > > > In crb_map_io() function, __crb_request_locality() is called prior to > > > crb_cmd_ready(), but if one of the consecutive function fails the flow > > > bails out instead of trying to relinquish locality. > > > This patch adds goto jump to __crb_relinquish_locality() on the error > > > path. > > > > > > Fixes: 888d867df441 (tpm: cmd_ready command can be issued only after > > > granting > > > locality) > > > Signed-off-by: Tomas Winkler > > > --- > > > drivers/char/tpm/tpm_crb.c | 10 +++++++--- > > > 1 file changed, 7 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c > > > index 7f78482cd157..34fbc6cb097b 100644 > > > --- a/drivers/char/tpm/tpm_crb.c > > > +++ b/drivers/char/tpm/tpm_crb.c > > > @@ -511,8 +511,10 @@ static int crb_map_io(struct acpi_device *device, > > > struct crb_priv *priv, > > > > > > priv->regs_t = crb_map_res(dev, priv, &io_res, buf- > > > >control_address, > > > sizeof(struct crb_regs_tail)); > > > - if (IS_ERR(priv->regs_t)) > > > - return PTR_ERR(priv->regs_t); > > > + if (IS_ERR(priv->regs_t)) { > > > + ret = PTR_ERR(priv->regs_t); > > > + goto out_relinquish_locality; > > > + } > > > > > > /* > > > * PTT HW bug w/a: wake up the device to access @@ -520,7 +522,7 > > > > @@ > > > static int crb_map_io(struct acpi_device *device, struct crb_priv > > > *priv, > > > */ > > > ret = crb_cmd_ready(dev, priv); > > > if (ret) > > > - return ret; > > > + goto out_relinquish_locality; > > > > > > pa_high = ioread32(&priv->regs_t->ctrl_cmd_pa_high); > > > pa_low = ioread32(&priv->regs_t->ctrl_cmd_pa_low); > > > @@ -565,6 +567,8 @@ static int crb_map_io(struct acpi_device *device, > > > struct crb_priv *priv, > > > > > > crb_go_idle(dev, priv); > > > > > > +out_relinquish_locality: > > > + > > > __crb_relinquish_locality(dev, priv, 0); > > > > > > return ret; > > > > Thanks, please just call it before returning in the error path. > > Can you please elaborate why, isn't the centralized exiting of functions > preferred kernel coding style? > https://www.kernel.org/doc/html/v4.11/process/coding-style.html#centralized-ex > iting-of-functions You exit only from one location (not multiple) and not from a nested context. Here you just add more complexity by doing this. /Jarkko