Re: [PATCH] misc/cs5535: Fix section mismatch derived fromcs5535_mfgpt_drv variable

[Andres Salomon]

On Mon, 3 Jan 2011 21:50:19 +0100
Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:

> On Mon, Jan 03, 2011 at 12:34:31PM -0800, Andres Salomon wrote:
> > On Mon, 3 Jan 2011 20:51:31 +0100
> > Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
> > 
> > > On Mon, Jan 03, 2011 at 11:43:10AM -0800, Andrew Morton wrote:
> > > > On Mon,  3 Jan 2011 03:51:28 +0100
> > > > Sedat Dilek <sedat.dilek@xxxxxxxxxxxxxx> wrote:
> > > > 
> > > > > >From my build.log:
> > > > > 
> > > > > WARNING: drivers/misc/cs5535-mfgpt.o(.data+0x0): Section
> > > > > mismatch in reference from the variable cs5535_mfgpt_drv to
> > > > > the function .devinit.text:cs5535_mfgpt_probe() The variable
> > > > > cs5535_mfgpt_drv references the function __devinit
> > > > > cs5535_mfgpt_probe() If the reference is valid then annotate
> > > > > the variable with __init* or __refdata (see linux/init.h) or
> > > > > name the variable: *driver, *_template, *_timer, *_sht,
> > > > > *_ops, *_probe, *_probe_one, *_console,
> > > > 
> > > > Confused.  cs5535_mfgpt_probe() _does_ have a name of the form
> > > > "*_probe", so why did it warn?
> > > 
> > > The varibale need to follow the naming scheme.
> > > In this case the function was named *_probe - which has no
> > > significance in the section mismatch checks.
> > > 
> > > > > variable with __init* or __refdata (see linux/init.h) or name
> > > > > the variable:
> > >     ^^^^^^^^
> > > ^^^^^^^^^ 
> > > 
> > > 	Sam
> > 
> > I see.  So it should really be renamed cs5535_mfgpt_driver, or _drv
> > added to the whitelist.  Or the whitelist dropped, and all drivers
> > changed to explicitly mark the structs with __devinitdata.
> 
> It is preferred that the variables are annotated __refdata.

Should they not be devinitdata, since they're structures referencing
devinit (ie, hotplug init) hooks?

The two places where I traditionally went for documentation on such
things was linux/init.h and Documentation/PCI/pci.txt.  The latter
states:

        __devinit       Device initialization code.
                        Identical to __init if the kernel is not
        compiled with CONFIG_HOTPLUG, normal function otherwise.

        o Do not mark the struct pci_driver.

linux/init.h says:

 * modpost not to issue a warning.  Intended semantics is that a code or
 * data tagged __ref* can reference code or data from init section
   without
 * producing a warning (of course, no warning does not mean code is
 * correct, so optimally document why the __ref is needed and why it's
   OK).


It would be nice to know why refdata is correct here, and devinitdata
is not.
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