Re: [PATCH 2/4] remoteproc: Split firmware name allocation from rproc_alloc()

From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Alex Elder <elder@linaro.org>, Ohad Ben-Cohen <ohad@wizery.com>,
	Suman Anna <s-anna@ti.com>,
	linux-remoteproc <linux-remoteproc@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/4] remoteproc: Split firmware name allocation from rproc_alloc()
Date: Tue, 14 Apr 2020 09:43:22 -0600	[thread overview]
Message-ID: <CANLsYkx69cZotLUrt170XYiYxpkTGKBNC8FUioBD=OSnDYm46Q@mail.gmail.com> (raw)
In-Reply-To: <20200414005506.GG20625@builder.lan>

Hi guys,

On Mon, 13 Apr 2020 at 18:54, Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
>
> On Mon 13 Apr 13:56 PDT 2020, Alex Elder wrote:
>
> > On 4/13/20 2:33 PM, Mathieu Poirier wrote:
> > > Make the firmware name allocation a function on its own in order to
> > > introduce more flexibility to function rproc_alloc().
> > >
> > > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> >
> > I didn't look at the larger context (MCU series); I'm only looking
> > at this (and the others in this series) in isolation.  I like
> > that you're encapsulating this stuff into functions but doing so
> > doesn't really add any flexibility.
> >
> > Two small suggestions for you to consider but they're truly
> > more about style so it's entirely up to you.  Outside of that
> > this looks straightforward to me, and the result of the series
> > is an improvement.
> >
> > I'll let you comment on my suggestions before offering my
> > "reviewed-by" indication.
> >
> >                                       -Alex
> >
> > > ---
> > >  drivers/remoteproc/remoteproc_core.c | 66 ++++++++++++++++------------
> > >  1 file changed, 39 insertions(+), 27 deletions(-)
> > >
> > > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> > > index 80056513ae71..4dee63f319ba 100644
> > > --- a/drivers/remoteproc/remoteproc_core.c
> > > +++ b/drivers/remoteproc/remoteproc_core.c
> > > @@ -1979,6 +1979,33 @@ static const struct device_type rproc_type = {
> > >     .release        = rproc_type_release,
> > >  };
> > >
> > > +static int rproc_alloc_firmware(struct rproc *rproc,
> > > +                           const char *name, const char *firmware)
> > > +{
> > > +   char *p, *template = "rproc-%s-fw";
> > > +   int name_len;
> >
> > Not a big deal (and maybe it's not consistent with other nearby
> > style) but template and name_len could be defined inside the
> > "if (!firmware)" block.
> >
>
> I prefer variables declared in the beginning of the function, so I'm
> happy with this.
>
> > > +   if (!firmware) {
> > > +           /*
> > > +            * If the caller didn't pass in a firmware name then
> > > +            * construct a default name.
> > > +            */
> > > +           name_len = strlen(name) + strlen(template) - 2 + 1;
> > > +           p = kmalloc(name_len, GFP_KERNEL);
> >
> >
> > I don't know if it would be an improvement, but you could
> > check for a null p value below for both cases.  I.e.:
> >
> >               if (p)
> >                       snprintf(p, ...);
> >
>
> Moving the common NULL check and return out seems nice, but given that
> we then have to have this positive conditional I think the end result is
> more complex.
>
> That said, if we're not just doing a verbatim copy from rproc_alloc() I
> think we should make this function:
>
>         if (!firmware)
>                 p = kasprintf(GFP_KERNEL, "rproc-%s-fw", name);
>         else
>                 p = kstrdup_const(firmware, GFP_KERNEL);
>
>         rproc->firmware = p;
>
>         return p ? 0 : -ENOMEM;

At this time I was going for a pure re-arrangement of the code and
avoiding further improvement.  This is simple enough that it can be
rolled-in the next revision.

Thanks,
Mathieu

>
> Regards,
> Bjorn
>
> > (more below)
> >
> > > +           if (!p)
> > > +                   return -ENOMEM;
> > > +           snprintf(p, name_len, template, name);
> > > +   } else {
> > > +           p = kstrdup(firmware, GFP_KERNEL);
> > > +           if (!p)
> > > +                   return -ENOMEM;
> > > +   }
> > > +
> >
> >       if (!p)
> >               return -ENOMEM;
> >
> > > +   rproc->firmware = p;
> > > +
> > > +   return 0;
> > > +}
> > > +
> > >  /**
> > >   * rproc_alloc() - allocate a remote processor handle
> > >   * @dev: the underlying device
> > > @@ -2007,42 +2034,21 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
> > >                       const char *firmware, int len)
> > >  {
> > >     struct rproc *rproc;
> > > -   char *p, *template = "rproc-%s-fw";
> > > -   int name_len;
> > >
> > >     if (!dev || !name || !ops)
> > >             return NULL;
> > >
> > > -   if (!firmware) {
> > > -           /*
> > > -            * If the caller didn't pass in a firmware name then
> > > -            * construct a default name.
> > > -            */
> > > -           name_len = strlen(name) + strlen(template) - 2 + 1;
> > > -           p = kmalloc(name_len, GFP_KERNEL);
> > > -           if (!p)
> > > -                   return NULL;
> > > -           snprintf(p, name_len, template, name);
> > > -   } else {
> > > -           p = kstrdup(firmware, GFP_KERNEL);
> > > -           if (!p)
> > > -                   return NULL;
> > > -   }
> > > -
> > >     rproc = kzalloc(sizeof(struct rproc) + len, GFP_KERNEL);
> > > -   if (!rproc) {
> > > -           kfree(p);
> > > +   if (!rproc)
> > >             return NULL;
> > > -   }
> > > +
> > > +   if (rproc_alloc_firmware(rproc, name, firmware))
> > > +           goto free_rproc;
> > >
> > >     rproc->ops = kmemdup(ops, sizeof(*ops), GFP_KERNEL);
> > > -   if (!rproc->ops) {
> > > -           kfree(p);
> > > -           kfree(rproc);
> > > -           return NULL;
> > > -   }
> > > +   if (!rproc->ops)
> > > +           goto free_firmware;
> > >
> > > -   rproc->firmware = p;
> > >     rproc->name = name;
> > >     rproc->priv = &rproc[1];
> > >     rproc->auto_boot = true;
> > > @@ -2091,6 +2097,12 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
> > >     rproc->state = RPROC_OFFLINE;
> > >
> > >     return rproc;
> > > +
> > > +free_firmware:
> > > +   kfree(rproc->firmware);
> > > +free_rproc:
> > > +   kfree(rproc);
> > > +   return NULL;
> > >  }
> > >  EXPORT_SYMBOL(rproc_alloc);
> > >
> > >
> >