From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Stephen Boyd <swboyd@chromium.org>
Cc: Murali Nalajala <mnalajal@codeaurora.org>,
gregkh@linuxfoundation.org, rafael@kernel.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] base: soc: Handle custom soc information sysfs entries
Date: Thu, 3 Oct 2019 22:50:57 -0700 [thread overview]
Message-ID: <20191004055057.GH63675@minitux> (raw)
In-Reply-To: <5d96daca.1c69fb81.fe5e4.e623@mx.google.com>
On Thu 03 Oct 22:38 PDT 2019, Stephen Boyd wrote:
> Quoting Murali Nalajala (2019-10-03 16:51:50)
> > @@ -151,14 +156,16 @@ struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr
> >
> > ret = device_register(&soc_dev->dev);
> > if (ret)
> > - goto out3;
> > + goto out4;
> >
> > return soc_dev;
> >
> > -out3:
> > +out4:
> > ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
> > put_device(&soc_dev->dev);
> > soc_dev = NULL;
> > +out3:
> > + kfree(soc_attr_groups);
>
> This code is tricky. put_device(&soc_dev->dev) will call soc_release()
> so we set soc_dev to NULL before calling kfree() on the error path. This
> way we don't doubly free a pointer that the release function will take
> care of. I wonder if the release function could free the ida as well,
> and then we could just make the device_register() failure path call
> put_device() and return ERR_PTR(ret) directly. Then the error path is
> simpler because we can avoid changing two pointers to NULL to avoid the
> double free twice. Or just inline the ida remove and put_device() call
> in the if and then goto out1 to consolidate the error pointer
> conversion.
>
But if we instead allocates the ida before the soc_dev, wouldn't the
error path be something like?:
foo:
put_device(&soc_dev->dev);
bar:
ida_simple_remove(&soc_ida, soc_num);
return err;
I think we still need two exit paths from soc_device_register()
regardless of moving the ida_simple_remove() into the release, but we
could drop it from the unregister(). So not sure if this is cleaner...
Regards,
Bjorn
> > out2:
> > kfree(soc_dev);
> > out1:
next prev parent reply other threads:[~2019-10-04 5:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-03 23:51 [PATCH v1] base: soc: Handle custom soc information sysfs entries Murali Nalajala
2019-10-04 5:38 ` Stephen Boyd
2019-10-04 5:50 ` Bjorn Andersson [this message]
2019-10-04 6:17 ` Stephen Boyd
2019-10-04 7:05 ` Greg KH
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