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From: "Nuno Sá" <noname.nuno@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Rodrigo Alencar <455.rodrigo.alencar@gmail.com>,
	 rodrigo.alencar@analog.com, linux-iio@vger.kernel.org,
	devicetree@vger.kernel.org,  linux-kernel@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-hardening@vger.kernel.org,
	 Lars-Peter Clausen <lars@metafoo.de>,
	Michael Hennerich <Michael.Hennerich@analog.com>,
	 Jonathan Cameron <jic23@kernel.org>,
	David Lechner <dlechner@baylibre.com>,
	 Andy Shevchenko <andy@kernel.org>, Rob Herring <robh@kernel.org>,
	 Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	 Philipp Zabel <p.zabel@pengutronix.de>,
	Jonathan Corbet <corbet@lwn.net>,
	 Shuah Khan <skhan@linuxfoundation.org>,
	Kees Cook <kees@kernel.org>,
	 "Gustavo A. R. Silva" <gustavoars@kernel.org>
Subject: Re: [PATCH v6 06/16] iio: core: create local __iio_chan_prefix_emit() for reuse
Date: Fri, 19 Jun 2026 10:19:13 +0100	[thread overview]
Message-ID: <ajUI9nNvTS3sZsB-@nsa> (raw)
In-Reply-To: <ajQ1bZSNHQ96pyJx@ashevche-desk.local>

On Thu, Jun 18, 2026 at 09:14:05PM +0300, Andy Shevchenko wrote:
> On Thu, Jun 18, 2026 at 05:14:19PM +0100, Rodrigo Alencar wrote:
> > On 18/06/26 16:06, Nuno Sá wrote:
> > > On Thu, Jun 18, 2026 at 02:27:22PM +0100, Rodrigo Alencar via B4 Relay wrote:
> 
> ...
> 
> > > > +	dev_attr->attr.name = kasprintf(GFP_KERNEL, "%s%s", prefix, postfix);
> > > > +	if (!dev_attr->attr.name)
> > > >  		return -ENOMEM;
> > > 
> > > I don't oppose the change. Looks like a nice cleanup.
> 
> May I oppose it? I found use scnprintf() is harder to follow in comparison to
> nice kasprintf() that takes care for the dynamically allocated buffer.

Tend to agree a bit given I was used to the older code. So matching the
old logic with the new one is an exercise, yes.

> 
> Also there is a chance to get a name silently cut due to insufficient space.
> Besides that this function can't be used (again due to 'c') in kasprintf()-like
> wrapper. I do not consider this as a good approach. Have you looked at seq_buf
> instead?

Not so sure the above bothers me that much.

> 
> > > But bear in mind this very sensible as any subtle mistake means ABI breakage.
> 
> Which immediately raises a question of test coverage. Do we have one? If not,
> this code must be accompanied with one.

The above is the more concerning part to me.

- Nuno Sá

> 
> > Yes! I tried to be careful... this is dangerous stuff!
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

  parent reply	other threads:[~2026-06-19  9:18 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-18 13:27 [PATCH v6 00/16] AD9910 Direct Digital Synthesizer Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 01/16] iio: ABI: add attributes for altcurrent channels Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 02/16] iio: ABI: scale and offset for frequency/phase channels Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 03/16] iio: ABI: add parent entry for iio channels Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 04/16] iio: add IIO_FREQUENCY channel type Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 05/16] iio: core: support 64-bit register through debugfs Rodrigo Alencar via B4 Relay
2026-06-18 14:45   ` Nuno Sá
2026-06-18 13:27 ` [PATCH v6 06/16] iio: core: create local __iio_chan_prefix_emit() for reuse Rodrigo Alencar via B4 Relay
2026-06-18 15:06   ` Nuno Sá
2026-06-18 16:14     ` Rodrigo Alencar
2026-06-18 18:14       ` Andy Shevchenko
2026-06-19  7:43         ` Rodrigo Alencar
2026-06-19  9:20           ` Nuno Sá
2026-06-19  9:19         ` Nuno Sá [this message]
2026-06-19  9:16       ` Nuno Sá
2026-06-18 13:27 ` [PATCH v6 07/16] iio: core: add hierarchical channel relationships Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 08/16] dt-bindings: iio: frequency: add ad9910 Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 09/16] iio: frequency: ad9910: initial driver implementation Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 10/16] iio: frequency: ad9910: add basic parallel port support Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 11/16] iio: frequency: ad9910: add digital ramp generator support Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 12/16] iio: frequency: ad9910: add RAM mode support Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 13/16] iio: frequency: ad9910: add output shift keying support Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 14/16] iio: frequency: ad9910: show channel priority in debugfs Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 15/16] iio: ABI: add docs for ad9910 sysfs entries Rodrigo Alencar via B4 Relay
2026-06-18 13:27 ` [PATCH v6 16/16] docs: iio: add documentation for ad9910 driver Rodrigo Alencar via B4 Relay

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