Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755523AbbFQNtu (ORCPT ); Wed, 17 Jun 2015 09:49:50 -0400 Received: from hofr.at ([212.69.189.236]:37993 "EHLO mail.hofr.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754059AbbFQNtl (ORCPT ); Wed, 17 Jun 2015 09:49:41 -0400 Date: Wed, 17 Jun 2015 15:49:39 +0200 From: Nicholas Mc Guire To: Gregory CLEMENT Cc: Wolfram Sang , Nicholas Mc Guire , Thomas Petazzoni , Maxime Ripard , Andrew Lunn , Chen-Yu Tsai , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] i2c: mv64xxx: remove unreachable signal case handling Message-ID: <20150617134939.GA23842@opentech.at> References: <1434036453-23336-1-git-send-email-hofrat@osadl.org> <20150617130030.GG13393@katana> <5581731B.10506@free-electrons.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5581731B.10506@free-electrons.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4004 Lines: 108 On Wed, 17 Jun 2015, Gregory CLEMENT wrote: > Hi Wolfram, Nicholas, > > On 17/06/2015 15:00, Wolfram Sang wrote: > > On Thu, Jun 11, 2015 at 05:27:33PM +0200, Nicholas Mc Guire wrote: > >> 'commit d295a86eab20 ("i2c: mv64xxx: work around signals causing I2C > >> transactions to be aborted")' removed the wait_event_interruptible_timeout > >> to prevent half/mixed i2c messages from being sent/received but forgot to > >> drop the signal received cases in the return handling. This just removes > >> this dead code and simplifies the error message as "time_left" only can be > >> 0 here and thus it conveys no additional information. > >> > >> Signed-off-by: Nicholas Mc Guire > >> --- > >> > >> Patch was compile tested with multi_v7_defconfig > >> (implies CONFIG_I2C_MV64XXX=y) > >> > >> Patch is against 4.1-rc7 (localversion-next is -next-20150611) > > > > Hmm, IMO this patch is too intrusive to be applied without actual > > testing. > > > >> > >> drivers/i2c/busses/i2c-mv64xxx.c | 15 +++------------ > >> 1 file changed, 3 insertions(+), 12 deletions(-) > >> > >> diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c > >> index 30059c1..a4f8ece 100644 > >> --- a/drivers/i2c/busses/i2c-mv64xxx.c > >> +++ b/drivers/i2c/busses/i2c-mv64xxx.c > >> @@ -534,7 +534,6 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data) > >> { > >> long time_left; > >> unsigned long flags; > >> - char abort = 0; > >> > >> time_left = wait_event_timeout(drv_data->waitq, > >> !drv_data->block, drv_data->adapter.timeout); > >> @@ -542,25 +541,17 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data) > >> spin_lock_irqsave(&drv_data->lock, flags); > >> if (!time_left) { /* Timed out */ > >> drv_data->rc = -ETIMEDOUT; > >> - abort = 1; > >> - } else if (time_left < 0) { /* Interrupted/Error */ > >> - drv_data->rc = time_left; /* errno value */ > >> - abort = 1; > >> - } > >> - > >> - if (abort && drv_data->block) { > >> drv_data->aborting = 1; > >> spin_unlock_irqrestore(&drv_data->lock, flags); > >> > >> time_left = wait_event_timeout(drv_data->waitq, > >> !drv_data->block, drv_data->adapter.timeout); > >> > >> - if ((time_left <= 0) && drv_data->block) { > > > > I am especially unsure about the drv_data->block removal. Did you double > > check if we can do this? > > The consideration was * wait_event_timeout was checkign !drv_data->block - so it it returned the condition held OR timeout * since it was a timeout here the condition was NOT met so either both are true or both are wrong I think the current logic only makes sense if one assumes that a signal case is also possible. > >> + if (time_left == 0) { > >> drv_data->state = MV64XXX_I2C_STATE_IDLE; > >> dev_err(&drv_data->adapter.dev, > >> - "mv64xxx: I2C bus locked, block: %d, " > >> - "time_left: %d\n", drv_data->block, > >> - (int)time_left); > >> + "mv64xxx: I2C bus locked, block: %d\n", > >> + drv_data->block); > > > > And if so, shouldn't that also be always 1 in the output here? > > yes drv_data->block is 0 | 1 only - so that probably could be dropped as well > >> mv64xxx_i2c_hw_init(drv_data); > >> } > >> } else > > > > Maybe (not sure) it also helps to split the patch into everything > > dealing with time_left as patch 1) and simplifying by drv_data->block > > removal as patch2? > > I agree. I would like to see 2 patches. The first one should be not controversial > and could be applied whereas the second one will need a deeper review. > thanks - will refactor and split it into two parts and see if I can get this tested somehow - no urgency as its really only cleanup. thx! hofrat -- 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/