LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Greg KH <greg@kroah.com>
To: Grant Grundler <grundler@parisc-linux.org>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
linux-pci@atrey.karlin.mff.cuni.cz, Andrew Morton <akpm@osdl.org>,
e1000-devel@lists.sourceforge.net, linux-scsi@vger.kernel.org,
Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Subject: Re: [PATCH 1/5] Update Documentation/pci.txt
Date: Fri, 15 Dec 2006 09:02:07 -0800 [thread overview]
Message-ID: <20061215170207.GB15058@kroah.com> (raw)
In-Reply-To: <20061210072508.GA12272@colo.lackof.org>
On Sun, Dec 10, 2006 at 12:25:08AM -0700, Grant Grundler wrote:
> On Tue, Dec 05, 2006 at 11:26:51PM -0800, Greg KH wrote:
> ...
> > I do have a few minor comments:
> ...
> > > Please mark the initialization and cleanup functions where appropriate
> > > (the corresponding macros are defined in <linux/init.h>):
> > >
> > > __init Initialization code. Thrown away after the driver
> > > initializes.
> > > __exit Exit code. Ignored for non-modular drivers.
> > > __devinit Device initialization code. Identical to __init if
> > > the kernel is not compiled with CONFIG_HOTPLUG, normal
> > > function otherwise.
> > > __devexit The same for __exit.
> > >
> > > Tips on marks:
> > > o The module_init()/module_exit() functions (and all initialization
> > > functions called _only_ from these) should be marked __init/__exit.
> > >
> > > o The struct pci_driver shouldn't be marked with any of these tags.
> > >
> > > o The ID table array should be marked __devinitdata.
> > >
> > > o The probe() and remove() functions (and all initialization
> > > functions called only from these) should be marked __devinit
> > > and __devexit.
> > >
> > > o If the driver is not a hotplug driver then use only
> > > __init/__exit and __initdata/__exitdata.
> >
> > No, don't say this, pci drivers are not "hotplug drivers",
>
> agreed - removed that bullet item.
>
> > and since CONFIG_HOTPLUG is really hard to turn off these days,
> > don't confuse people with the devinit stuff. Everyone gets it wrong...
>
> While revisiting this bit, I started thinking:
>
> o While I agree HOTPLUG is essential to desktop and server,
> I don't think that's true for "embedded" (e.g. routers/switches).
Agreed, but those are the minority.
> o drivers should use __dev* exactly because HOTPLUG is defined.
Yes, they should, but it is confusing as to why it should be used in
places, and __init used in others. If you want to detail the
differences better than the current documentation does, please do.
> o Why does everyone get __dev* wrong? Bad API? Missing or bad Documentation?
> [ This is not a free-for-all...I'd like a clear answer from
> Greg what would help driver writers get this right. ]
They get it wrong usually because they cut-and-paste from others. The
proof of that is seeing __dev* used in pci hotplug controller drivers :)
I'm just pointing out that about every 6 months I have to sweep the tree
and fix up all of the improper usages. And the whole __devexit_p()
stuff is usually used incorrectly too.
> o Prefer a seperate patch to clean this up?
> Take what I have for now and sort out the __devinit handling in
> another round?
>
> o Note what I have is essentially the original text - just reformatted
> to be a bit more readable.
>
> o Hrm...what did greg mean with "it"? All of the markers?
> Or just the __dev* markers?
Just the __dev stuff.
> > > o Pointers to functions marked as __devexit must be created using
> > > __devexit_p(function_name). That will generate the function
> > > name or NULL if the __devexit function will be discarded.
> >
> > I really recommend just not using any of these for almost all PCI
> > drivers, as the space savings just really isn't there...
>
> It's a bit too late for that, no?
> And even if it's more of a PITA than it's worth, we do save something:
>
> # hppa64-linux-gnu-readelf -S vmlinux
> ...
> [26] .init.text PROGBITS 0000000040598000 00457000
> 0000000000022280 0000000000000000 AX 0 0 8
> [27] .init.data PROGBITS 00000000405ba280 00479280
> 000000000001faf0 0000000000000000 WA 0 0 8
> ...
>
> Reality is they are used in _alot_ of drivers.
> I checked 2.6.19:
> grundler <514>find -name \*.c | xargs fgrep __devinit | wc
> 2723 16812 235863
>
> I'd prefer to keep the short references here if you
> don't mind too much. At least until you can get some
> consensus that __init and __exit should go away
> or get replaced by easier-to-get-right markers.
Ok, just describe them properly and we should be fine.
thanks,
greg k-h
next prev parent reply other threads:[~2006-12-15 17:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-22 8:05 Hidetoshi Seto
2006-11-22 8:54 ` Arjan van de Ven
2006-11-22 18:28 ` Grant Grundler
2006-11-24 0:38 ` Hidetoshi Seto
2006-11-24 5:12 ` Grant Grundler
2006-11-24 6:05 ` Hidetoshi Seto
2006-12-06 7:26 ` Greg KH
2006-12-07 3:55 ` Grant Grundler
2006-12-10 7:25 ` Grant Grundler
2006-12-15 17:02 ` Greg KH [this message]
2006-12-18 7:11 ` Grant Grundler
2006-12-22 19:46 ` Randy Dunlap
2006-12-22 21:52 ` Stefan Richter
2006-12-24 6:11 ` Grant Grundler
2006-12-24 6:07 ` [PATCH] Update Documentation/pci.txt v7 Grant Grundler
2006-12-24 19:16 ` Randy Dunlap
2006-12-25 7:59 ` Grant Grundler
2006-12-25 8:06 ` Grant Grundler
2006-12-25 8:08 ` Grant Grundler
2007-01-02 21:45 ` Greg KH
2007-01-03 7:15 ` Grant Grundler
2006-12-25 9:04 ` Kenji Kaneshige
2007-01-16 22:26 ` patch pci-rework-documentation-pci.txt.patch added to gregkh-2.6 tree gregkh
2007-01-17 9:10 ` Jiri Slaby
2007-01-17 19:21 ` Greg KH
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20061215170207.GB15058@kroah.com \
--to=greg@kroah.com \
--cc=akpm@osdl.org \
--cc=e1000-devel@lists.sourceforge.net \
--cc=grundler@parisc-linux.org \
--cc=kaneshige.kenji@jp.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@atrey.karlin.mff.cuni.cz \
--cc=linux-scsi@vger.kernel.org \
--cc=seto.hidetoshi@jp.fujitsu.com \
--subject='Re: [PATCH 1/5] Update Documentation/pci.txt' \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).