From: "Ardelean, Alexandru" <alexandru.Ardelean@analog.com>
To: "keescook@chromium.org" <keescook@chromium.org>,
"andy.shevchenko@gmail.com" <andy.shevchenko@gmail.com>
Cc: "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
"Grozav, Andrei" <Andrei.Grozav@analog.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"jic23@kernel.org" <jic23@kernel.org>,
"lars@metafoo.de" <lars@metafoo.de>,
"Hennerich, Michael" <Michael.Hennerich@analog.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Csomortani, Istvan" <Istvan.Csomortani@analog.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"Bogdan, Dragos" <Dragos.Bogdan@analog.com>,
"Nagy, Laszlo" <Laszlo.Nagy@analog.com>,
"Costina, Adrian" <Adrian.Costina@analog.com>
Subject: Re: [PATCH v11 5/8] iio: adc: adi-axi-adc: add support for AXI ADC IP core
Date: Sun, 22 Mar 2020 16:44:16 +0000 [thread overview]
Message-ID: <80fa6f767f0a1f7f26564050bfd88b880bdecc1e.camel@analog.com> (raw)
In-Reply-To: <db236d3feebf1a84e17787bd519e76f265199ea9.camel@analog.com>
On Sun, 2020-03-22 at 16:31 +0000, Ardelean, Alexandru wrote:
> [External]
>
> On Sun, 2020-03-22 at 09:16 -0700, Kees Cook wrote:
> > On Sun, Mar 22, 2020 at 12:45:39PM +0200, Andy Shevchenko wrote:
> > > +Cc Kees (see below about allocation size checks)
> > >
> > > On Sun, Mar 22, 2020 at 11:36 AM Ardelean, Alexandru
> > > <alexandru.Ardelean@analog.com> wrote:
> > > > On Sat, 2020-03-21 at 23:38 +0200, Andy Shevchenko wrote:
> > > > > On Sat, Mar 21, 2020 at 10:55 AM Alexandru Ardelean
> > > > > <alexandru.ardelean@analog.com> wrote:
> > >
> > > ...
> > >
> > > > > > +static struct adi_axi_adc_conv *adi_axi_adc_conv_register(struct
> > > > > > device
> > > > > > *dev,
> > > > > > + int
> > > > > > sizeof_priv)
> > > > > > +{
> > > > > > + struct adi_axi_adc_client *cl;
> > > > > > + size_t alloc_size;
> > > > > > +
> > > > > > + alloc_size = sizeof(struct adi_axi_adc_client);
> > > > > > + if (sizeof_priv) {
> > > > > > + alloc_size = ALIGN(alloc_size, IIO_ALIGN);
> > > > > > + alloc_size += sizeof_priv;
> > > > > > + }
> > > > > > + alloc_size += IIO_ALIGN - 1;
> > > > >
> > > > > Have you looked at linux/overflow.h?
> > > >
> > > > i did now;
> > > > any hints where i should look closer?
> > >
> > > It seems it lacks of this kind of allocation size checks... Perhaps add
> > > one?
> > > Kees, what do you think?
> > >
> > > > > > + cl = kzalloc(alloc_size, GFP_KERNEL);
> > > > > > + if (!cl)
> > > > > > + return ERR_PTR(-ENOMEM);
> >
> > My head hurts trying to read this! ;) Okay, so the base size is
> > sizeof(struct adi_axi_adc_client). But if sizeof_priv is non-zero
> > (this arg should be size_t not int), then we need to make the struct
> > size ALIGNed? And then what is the "+= IIO_ALIGN - 1" for?
> >
> > It's not clear to me what the expect alignment/padding is here.
> >
> > I would probably construct this as:
> >
> > sizeof_self = sizeof(struct adi_axi_adc_client);
> > if (sizeof_priv)
> > sizeof_self = ALIGN(sizeof_self, IIO_ALIGN);
> > if (check_add_overflow(sizeof_self, sizeof_priv, &sizeof_alloc))
> > return ERR_PTR(-ENOMEM);
> > if (check_add_overflow(sizeof_alloc, IIO_ALIGN - 1, &sizeof_alloc))
> > return ERR_PTR(-ENOMEM);
>
> Ok, but the question is: shouldn't this be done in kmalloc()/kzalloc?
> Why do it in each driver?
> I don't see this done in many drivers.
Disregard this comment.
It's late here, and I'm having trouble reading the code.
But, this feels a bit weird popping up now, when trying to re-use code that
already existed in parts of IIO.
All I did was copy bits from iio_device_alloc(), and now it seems I have to
write compiler/overflow checks.
>
> > But I don't understand the "IIO_ALIGN - 1" part, so I assume this could
> > be shortened with better use of ALIGN()?
> >
> > Also, this feels like a weird driver allocation overall:
> >
> > + struct adi_axi_adc_conv **ptr, *conv;
> > +
> > + ptr = devres_alloc(devm_adi_axi_adc_conv_release, sizeof(*ptr),
> > + GFP_KERNEL);
> > + if (!ptr)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + conv = adi_axi_adc_conv_register(dev, sizeof_priv);
> >
> > devres_alloc() allocates storage for a _single pointer_. :P That's not
> > useful for resource tracking. Why is devres_alloc() being called here
> > and not down in adi_axi_adc_conv_register() and just passing the pointer
> > back up?
This was initially implemented as having 2 parts: 1 adi_axi_adc_conv_register()
and 1 devm_adi_axi_adc_conv_register() which were both exported.
It was deciced earlier to remove the adi_axi_adc_conv_register() part.
> >
next prev parent reply other threads:[~2020-03-22 16:44 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-21 8:53 [PATCH v11 0/8] iio: adi-axi-adc,ad9647: Add support for AD9467 ADC Alexandru Ardelean
2020-03-21 8:53 ` [PATCH v11 1/8] include: fpga: adi-axi-common.h: fixup whitespace tab -> space Alexandru Ardelean
2020-03-21 8:53 ` [PATCH v11 2/8] include: fpga: adi-axi-common.h: add version helper macros Alexandru Ardelean
2020-03-21 17:21 ` Jonathan Cameron
2020-03-21 8:53 ` [PATCH v11 3/8] iio: buffer-dmaengine: use %zu specifier for sprintf(align) Alexandru Ardelean
2020-03-21 17:22 ` Jonathan Cameron
2020-03-21 8:53 ` [PATCH v11 4/8] iio: buffer-dmaengine: add dev-managed calls for buffer alloc Alexandru Ardelean
2020-03-21 17:22 ` Jonathan Cameron
2020-03-21 8:53 ` [PATCH v11 5/8] iio: adc: adi-axi-adc: add support for AXI ADC IP core Alexandru Ardelean
2020-03-21 17:15 ` Jonathan Cameron
2020-03-21 21:38 ` Andy Shevchenko
2020-03-22 9:35 ` Ardelean, Alexandru
2020-03-22 10:45 ` Andy Shevchenko
2020-03-22 16:11 ` Ardelean, Alexandru
2020-03-22 16:16 ` Kees Cook
2020-03-22 16:31 ` Ardelean, Alexandru
2020-03-22 16:44 ` Ardelean, Alexandru [this message]
2020-03-22 16:53 ` Jonathan Cameron
2020-03-22 17:40 ` Ardelean, Alexandru
2020-03-22 18:26 ` Jonathan Cameron
2020-03-24 7:10 ` Ardelean, Alexandru
2020-03-22 15:20 ` Jonathan Cameron
2020-03-21 8:53 ` [PATCH v11 6/8] dt-bindings: iio: adc: add bindings doc for AXI ADC driver Alexandru Ardelean
2020-03-21 17:23 ` Jonathan Cameron
2020-03-21 8:53 ` [PATCH v11 7/8] iio: adc: ad9467: add support AD9467 ADC Alexandru Ardelean
2020-03-21 17:23 ` Jonathan Cameron
2020-03-21 8:53 ` [PATCH v11 8/8] dt-bindings: iio: adc: add bindings doc for " Alexandru Ardelean
2020-03-21 17:24 ` Jonathan Cameron
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