Message-ID: <1458250430.9556.39.camel@perches.com>
Subject: Re: [PATCH v9 2/3] kernel.h: add to_user_ptr()
From: Joe Perches <joe@perches.com>
To: Gustavo Padovan <gustavo@padovan.org>
Cc: Rob Clark <robdclark@gmail.com>,
        Gustavo Padovan <gustavo.padovan@collabora.co.uk>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        devel@driverdev.osuosl.org,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        Daniel Stone <daniels@collabora.com>,
        Arve =?ISO-8859-1?Q?Hj=F8nnev=E5g?= <arve@android.com>,
        Riley Andrews <riandrews@android.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Greg Hackmann <ghackmann@google.com>,
        John Harrison <John.C.Harrison@intel.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel.vetter@intel.com>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Date: Thu, 17 Mar 2016 14:33:50 -0700
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On Thu, 2016-03-17 at 18:19 -0300, Gustavo Padovan wrote:
> 2016-03-17 Joe Perches <joe@perches.com>:
> > On Thu, 2016-03-17 at 16:50 -0400, Rob Clark wrote:
> > > On Thu, Mar 17, 2016 at 4:40 PM, Joe Perches <joe@perches.com> wrote:
> > []
> > > > It's a name that seems like it should be a straightforward
> > > > cast of a kernel pointer to a __user pointer like:
> > > > 
> > > > static inline void __user *to_user_ptr(void *p)
> > > > {
> > > > ????????return (void __user *)p;
> > > > }
> > > ahh, ok.??I guess I was used to using it in the context of ioctl
> > > structs..??in that context u64 -> (void __user *) made more sense.
> > > 
> > > Maybe uapi_to_ptr()???(ok, not super-creative.. maybe someone has a
> > > better idea)
> > Maybe u64_to_user_ptr?
> That is a good name. If everyone agrees I can resend this patch
> changing it to u64_to_user_ptr. Then should we still keep it on
> kernel.h?

I've no particular opinion about location,
but maybe compat.h might be appropriate.

Maybe add all variants:

	void __user *u32_to_user_ptr(u32 val)
	void __user *u64_to_user_ptr(u64 val)
	u32 user_ptr_to_u32(void __user *p)
	u64 user_ptr_to_u64(void __user *p)

Maybe there's something about 32 bit userspace on
64 OS that should be done too.