linux-kernel - Re: [PATCH 6/8] bus: mhi: core: Add support for processing priority of event ring

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 24 Jun 2021 20:20:06 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     hemantk@...eaurora.org, bbhatt@...eaurora.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        loic.poulain@...aro.org
Subject: Re: [PATCH 6/8] bus: mhi: core: Add support for processing priority
 of event ring

On Thu, Jun 24, 2021 at 04:40:38PM +0200, Greg KH wrote:
> On Thu, Jun 24, 2021 at 07:54:53PM +0530, Manivannan Sadhasivam wrote:
> > On Thu, Jun 24, 2021 at 03:53:33PM +0200, Greg KH wrote:
> > > On Mon, Jun 21, 2021 at 09:46:14PM +0530, Manivannan Sadhasivam wrote:
> > > > From: Hemant Kumar <hemantk@...eaurora.org>
> > > > 
> > > > Event ring priorities are currently set to 1 and are unused.
> > > > Default processing priority for event rings is set to regular
> > > > tasklet. Controllers can choose to use high priority tasklet
> > > > scheduling for certain event rings critical for processing such
> > > > as ones transporting control information if they wish to avoid
> > > > system scheduling delays for those packets. In order to support
> > > > these use cases, allow controllers to set event ring priority to
> > > > high.
> > > > 
> > > > Signed-off-by: Hemant Kumar <hemantk@...eaurora.org>
> > > > Signed-off-by: Bhaumik Bhatt <bbhatt@...eaurora.org>
> > > > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> > > > Link: https://lore.kernel.org/r/1624053903-24653-2-git-send-email-bbhatt@codeaurora.org
> > > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> > > > ---
> > > >  drivers/bus/mhi/core/init.c | 3 +--
> > > >  drivers/bus/mhi/core/main.c | 9 +++++++--
> > > >  include/linux/mhi.h         | 2 +-
> > > >  3 files changed, 9 insertions(+), 5 deletions(-)
> > > > 
> > > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> > > > index c81b377fca8f..444676034bf0 100644
> > > > --- a/drivers/bus/mhi/core/init.c
> > > > +++ b/drivers/bus/mhi/core/init.c

[...]

> > That's because, "1" was used from the beginning by the controller drivers
> > as the regular priority. And I thought of using "0" as high priority so
> > that we can leave the controller drivers unmodified.
> 
> There's no problem modifying everyone, how much work is that?
> 

I thought of minimizing the diff if we can avoid...err

> > > Shouldn't this be a boolean, or if not, an enumerated type so that
> > > people can read the code over time?
> > > 
> > 
> > Bhaumik proposed an enum but I wanted 0/1 so that the controller drivers
> > can be untouched. Also, I don't see any immediate requirement for other
> > priorities.
> > 
> > Will make it a bool then.
> 
> Rename it when you change it so that you know you catch all existing
> users.
> 

Okay. Bhaumik, can you please use the enum (as you did)?

Thanks,
Mani

> thanks,
> 
> greg k-h