linux-kernel - Re: [PATCH 1/2] Staging: gasket: implement apex_get

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Date:   Tue, 29 Oct 2019 17:22:24 +0200
From:   Samuil Ivanov <samuil.ivanovbg@...il.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        rspringer@...gle.com, toddpoynor@...gle.com, benchan@...omium.org
Subject: Re: [PATCH 1/2] Staging: gasket: implement apex_get_status() to
 check driver status

On Tue, Oct 29, 2019 at 09:10:07AM +0100, Greg KH wrote:
> On Tue, Oct 29, 2019 at 12:59:25AM +0200, Samuil Ivanov wrote:
> > >From the TODO:
> > - apex_get_status() should actually check status
> > 
> > The function now checkes the status of the driver
> > 
> > Signed-off-by: Samuil Ivanov <samuil.ivanovbg@...il.com>
> > ---
> >  drivers/staging/gasket/apex_driver.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/staging/gasket/apex_driver.c b/drivers/staging/gasket/apex_driver.c
> > index 46199c8ca441..a5dd6f3c367d 100644
> > --- a/drivers/staging/gasket/apex_driver.c
> > +++ b/drivers/staging/gasket/apex_driver.c
> > @@ -247,6 +247,9 @@ module_param(bypass_top_level, int, 0644);
> >  static int apex_get_status(struct gasket_dev *gasket_dev)
> >  {
> >  	/* TODO: Check device status. */
> > +	if (gasket_dev->status == GASKET_STATUS_DEAD)
> > +		return GASKET_STATUS_DEAD;
> > +
> 
> Have you tested this to verify that this is what is needed here?
> 
> thanks,
> 
> greg k-h

Hello Greg,

After going through the code again, I am sure this not what is needed here.

I thought that gasket_dev->status is already set to either
GASKET_STATUS_ALIVE of GASKET_STATUS_DEAD,
and all I needed to do is check it. It turns out that status
has to be set before that.

So what I found is that function gasket_get_hw_status()
in file gasket_core.c is used to determine the health of the Gasket device,
and other function use it to set gasket_dev->status and then check
the device status.

I think it should be something like this.
...
gasket_dev->status = gasket_get_hw_status(gasket_dev);
if (gasket_dev->status == GASKET_STATUS_DEAD) {
        dev_dbg(gasket_dev->dev, "Device reported as dead.\n");
        return -EINVAL;
}
return GASKET_STATUS_ALIVE;
...

I can try this, but I have no means of testing it.

Grt,
Samuil