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From: John Calixto <john.calixto@modsystems.com>
To: Chris Ball <cjb@laptop.org>
Cc: "Michał Mirosław" <mirqus@gmail.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	linux-mmc@vger.kernel.org,
	"Andrei Warkentin" <andreiw@motorola.com>
Subject: Re: [PATCH v6] mmc: Add mmc CMD+ACMD passthrough ioctl
Date: Wed, 20 Apr 2011 13:47:16 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.1104201341430.28361@peruna> (raw)
In-Reply-To: <BANLkTim4V9J1VahxynPQp_hv+r5j2-yK6w@mail.gmail.com>

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On Wed, 20 Apr 2011, Michał Mirosław wrote:
> >> I'm okay with the anon union + ``compat_ptr(*(u32 *))`` part of your
> >> solution.  If everyone else thinks it is reasonable, I'll submit a v7
> >> with it.
> > No need for a union or a ptr_size member in the struct. Just use
> > a single __u64 and let the user cast the pointer to that. This
> > will work on all architectures.
> 
> Union is just hiding this cast (it will be done in kernel) and allows
> cleaner code for userspace (there's a single kernel and possibly
> multiple applications that will implement this call).
> 

Chris,

Do you have a preference here?  I do not have a preference.  On the one
hand, not having the union makes for a cleaner-to-read struct.  On the
other hand, not having to cast the pointer in 32-bit userspace is nice
especially since I foresee using this ioctl on a lot of ARM SoCs.

John

  reply	other threads:[~2011-04-20 20:47 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-14  0:34 v6 changelog for mmc ioctl patch John Calixto
2011-04-14  0:38 ` [PATCH v6] mmc: Add mmc CMD+ACMD passthrough ioctl John Calixto
2011-04-20 17:12   ` John Calixto
2011-04-20 17:29     ` Chris Ball
2011-04-21 10:47       ` Arnd Bergmann
2011-04-20 17:31   ` Michał Mirosław
2011-04-20 17:38     ` John Calixto
2011-04-20 18:06       ` Michał Mirosław
2011-04-20 18:23     ` Michał Mirosław
2011-04-20 19:06       ` John Calixto
2011-04-20 19:17         ` Arnd Bergmann
2011-04-20 19:34           ` John Calixto
2011-04-20 19:38             ` Arnd Bergmann
2011-04-20 19:46           ` Michał Mirosław
2011-04-20 20:47             ` John Calixto [this message]
2011-04-20 22:28               ` Chris Ball
2011-04-21  5:11             ` Arnd Bergmann
2011-04-21 10:28               ` Michał Mirosław
2011-04-21 11:15                 ` Arnd Bergmann
2011-04-21 11:47                   ` Michał Mirosław
2011-04-21 12:39                     ` Arnd Bergmann
2011-04-21 13:40                       ` Michał Mirosław
2011-04-20 22:13   ` Chris Ball

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