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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
