From: Joe Perches <joe@perches.com>
To: Russell King - ARM Linux <linux@armlinux.org.uk>,
Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Javier Martinez Canillas <javierm@redhat.com>,
Mark Brown <broonie@kernel.org>,
linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH 1/3] driver core: add probe_err log helper
Date: Wed, 17 Oct 2018 18:45:36 -0700 [thread overview]
Message-ID: <c2c8f5186beff6bdc04cfe79292cedad20f36475.camel@perches.com> (raw)
In-Reply-To: <20181017112914.GH30658@n2100.armlinux.org.uk>
On Wed, 2018-10-17 at 12:29 +0100, Russell King - ARM Linux wrote:
> On Tue, Oct 16, 2018 at 04:55:00PM +0300, Andy Shevchenko wrote:
> > On Tue, Oct 16, 2018 at 3:55 PM Andrzej Hajda <a.hajda@samsung.com> wrote:
> > > On 16.10.2018 13:29, Andrzej Hajda wrote:
> > > > On 16.10.2018 13:01, Andy Shevchenko wrote:
> > > > > On Tue, Oct 16, 2018 at 10:22 AM Andrzej Hajda <a.hajda@samsung.com> wrote:
> > > > > > During probe every time driver gets resource it should usually check for error
> > > > > > printk some message if it is not -EPROBE_DEFER and return the error. This
> > > > > > pattern is simple but requires adding few lines after any resource acquisition
> > > > > > code, as a result it is often omited or implemented only partially.
> > > > > > probe_err helps to replace such code seqences with simple call, so code:
> > > > > > if (err != -EPROBE_DEFER)
> > > > > > dev_err(dev, ...);
> > > > > > return err;
> > > > > > becomes:
> > > > > > return probe_err(dev, err, ...);
> > > > > > + va_start(args, fmt);
> > > > > > +
> > > > > > + vaf.fmt = fmt;
> > > > > > + vaf.va = &args;
> > > > > > +
> > > > > > + __dev_printk(KERN_ERR, dev, &vaf);
> > > > > It would be nice to print an error code as well, wouldn't it?
> > > > Hmm, on probe fail error is printed anyway (with exception of
> > > > EPROBE_DEFER, ENODEV and ENXIO):
> > > > "probe of %s failed with error %d\n"
> > > > On the other side currently some drivers prints the error code anyway
> > > > via dev_err or similar, so I guess during conversion to probe_err it
> > > > should be removed then.
> > > >
> > > > If we add error code to probe_err is it OK to report it this way?
> > > > dev_err(dev, "%V, %d\n", &vaf, err);
> > >
> > > Ups, I forgot that message passed to probe_err will contain already
> > > newline character.
> >
> > You may consider not to pass it.
>
> It's normal to pass the '\n', so by doing this, we create the situation
> where this function becomes the exception to the norm. That's not a
> good idea - we will see people forget that appending '\n' should not
> be done for this particular function.
>
> While we could add a checkpatch rule, that's hassle (extra rework).
It would not be a simple checkpatch rule with high confidence
because of pr_cont uses that may not be in the patch context.
> In I think the message would be much better formatted if we did:
>
> dev_err(dev, "error %d: %V", err, &vaf);
s/%V/%pV/
next prev parent reply other threads:[~2018-10-18 1:45 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20181016072248eucas1p18943ce87e084797cd597afd4edb65a65@eucas1p1.samsung.com>
2018-10-16 7:22 ` [PATCH 0/3] driver core: add probe error check helper Andrzej Hajda
[not found] ` <CGME20181016072249eucas1p2303b8c06a9f7c839a971fe065b0c752e@eucas1p2.samsung.com>
2018-10-16 7:22 ` [PATCH 1/3] driver core: add probe_err log helper Andrzej Hajda
2018-10-16 9:32 ` Javier Martinez Canillas
2018-10-16 10:27 ` Mark Brown
2018-10-16 11:09 ` Greg Kroah-Hartman
2018-10-16 11:01 ` Andy Shevchenko
2018-10-16 11:29 ` Andrzej Hajda
[not found] ` <605bd00e-ed0d-4259-bdc3-1784b2b3b16a@samsung.com>
2018-10-16 12:55 ` Andrzej Hajda
2018-10-16 13:55 ` Andy Shevchenko
[not found] ` <CGME20181017085832eucas1p23dbb86230149a13634b8a091c3b1301f@eucas1p2.samsung.com>
2018-10-17 8:58 ` [PATCH v2 " Andrzej Hajda
2018-10-17 9:56 ` Mark Brown
2018-10-17 11:30 ` Andy Shevchenko
2018-10-17 11:49 ` Greg Kroah-Hartman
2018-10-17 11:29 ` [PATCH " Russell King - ARM Linux
2018-10-17 11:33 ` Andy Shevchenko
[not found] ` <CGME20181017132209eucas1p1d23615adc15663caaffb3c117dc61151@eucas1p1.samsung.com>
2018-10-17 13:22 ` [PATCH v3 1/4] " Andrzej Hajda
2018-10-18 1:45 ` Joe Perches [this message]
[not found] ` <CGME20181016072249eucas1p28855602564eb74a771fe521712962680@eucas1p2.samsung.com>
2018-10-16 7:22 ` [PATCH 2/3] driver core: add deferring probe reason to devices_deferred property Andrzej Hajda
2018-10-16 9:25 ` Mark Brown
2018-10-16 9:47 ` Javier Martinez Canillas
2018-10-16 13:42 ` Andy Shevchenko
[not found] ` <CGME20181017085952eucas1p2ff93b96d300aab2dc70b97bf266978ab@eucas1p2.samsung.com>
2018-10-17 8:59 ` [PATCH v2 " Andrzej Hajda
2018-10-17 11:35 ` Andy Shevchenko
[not found] ` <CGME20181017132404eucas1p2a413f6853af8f11a874650b6289d56cf@eucas1p2.samsung.com>
2018-10-17 13:24 ` [PATCH v3 2/4] " Andrzej Hajda
2018-10-17 14:17 ` Andy Shevchenko
[not found] ` <CGME20181018064916eucas1p22f03a19eb09cecdb0061dc5a4bf99ce6@eucas1p2.samsung.com>
2018-10-18 6:49 ` [PATCH v4 2/3] " Andrzej Hajda
[not found] ` <CGME20181016072250eucas1p1a763670c8509d20a6e6847eadb246817@eucas1p1.samsung.com>
2018-10-16 7:22 ` [PATCH 3/3] drivers: use probe_err function in obvious cases Andrzej Hajda
2018-10-16 9:52 ` Javier Martinez Canillas
2018-10-16 13:51 ` Andy Shevchenko
2018-10-17 9:10 ` Andrzej Hajda
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