linux-kernel - Re: [PATCH v5] i2c: imx: support DMA defer probing

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z2UK4rMxrtNsPw5V@pengutronix.de>
Date: Fri, 20 Dec 2024 07:12:50 +0100
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: Carlos Song <carlos.song@....com>
Cc: Andi Shyti <andi.shyti@...nel.org>, Frank Li <frank.li@....com>,
	"kernel@...gutronix.de" <kernel@...gutronix.de>,
	"shawnguo@...nel.org" <shawnguo@...nel.org>,
	"s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
	"festevam@...il.com" <festevam@...il.com>,
	"linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
	"imx@...ts.linux.dev" <imx@...ts.linux.dev>,
	"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Clark Wang <xiaoning.wang@....com>,
	Ahmad Fatoum <a.fatoum@...gutronix.de>
Subject: Re: [PATCH v5] i2c: imx: support DMA defer probing

On Fri, Dec 20, 2024 at 05:59:38AM +0000, Carlos Song wrote:
> > > So we make this logic. Anyway we let the I2C controller registered whether
> > DMA is available or not(except defer probe).
> > > Ignoring ENODEV and EPROBE_DEFER makes it looks like nothing happened if
> > DMA is defer probed or not enabled(This is an expected).
> > > However we still need i2c DMA status is known when meet an unexpected
> > error, so we use dev_err_probe() to print error.
> >
> > Why dev_err_probe() instead of dev_err()?
> >
> Hi,
> In patch V2 discussion, Marc suggested just return dev_err_probe(), but I don't accept it so I choose to use dev_err_probe() to print error in V3.[1]
> In this case, the two APIs have the same function, do you mean dev_err() is more suitable?

Yes, dev_err_probe() should be used in combination with return. For
example:
  return dev_err_probe(...);

It will pass the return value on exit of the function and optionally
print of the error message if it is not EPROBE_DEFER. Practically it
replace commonly used coding pattern:
  if (ret == -EPROBE_DEFER) {
    return ret;
  } else if (ret) {
    dev_err(..);
    return ret;
  }

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |