Re: [PATCH 1/4] uaccess: add copy_word_from_user

From: Steven Rostedt
Date: Wed Feb 25 2009 - 20:46:23 EST




On Wed, 25 Feb 2009, Andrew Morton wrote:

> btw,
>
> On Wed, 25 Feb 2009 15:30:08 -0500
> Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> > +int copy_word_from_user(void *to, const void __user *from,
> > + unsigned int copy, unsigned int read,
> > + unsigned int *copied, int skip)
>
> You presently have this not-exported-to-modules. Was that deliberate?

Nope, I didn't even think about it. I usually do the EXPORT_SYMBOL when
I have a need to export to a module. Not saying I left it out on purpose.
I left it out simply because I did not think about using it in a module
:-/

>
> There are arguments either way. Lately we've tended to take the
> position that a whole interface either is or is not wholly exported.
> The uaccess functions are exported, so this one should be as well.
>
> We can of course do that later on, when there's a user - I have no
> particular preference personally.
>
> <looks at probe_kernel_read and probe_kernel_write>
>
> These are really part of the uaccess interface too. I don't see a need
> for both lib/uaccess.c and mm/maccess.c?

Ah, I didn't notice that file. I could move this to that file, or move the
maccess to this file. I just thought lib would be a better location.
What would you suggest?

>
> probe_kernel_read() and probe_kernel_write() are EXPORT_SYMBOL_GPL,
> whereas the rest of the uaccess interface is EXPORT_SYMBOL. Ho hum.

Looks like another clean up. I guess probe_kernel is because it is more
kernel internals and should not be used by binary modules? Although
nothing prevents a kernel module from using the uaccess code for the
kernel. Or even make a fault section themselves.

-- Steve

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