From: Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: [RFC PATCH 1/5] new helper: iov_iter_rw()
Date: Mon, 16 Mar 2015 17:36:05 +0000
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To: Omar Sandoval <osandov@osandov.com>
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On Mon, Mar 16, 2015 at 04:33:49AM -0700, Omar Sandoval wrote:
> Get either READ or WRITE out of iter->type.

Umm...  

> + * Get one of READ or WRITE out of iter->type without any other flags OR'd in
> + * with it.
> + */
> +static inline int iov_iter_rw(const struct iov_iter *i)
> +{
> +	return i->type & RW_MASK;
> +}

TBH, I would turn that into a macro.  Reason: indirect includes.

How about

#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & RW_MASK)

Should do you all the type safety of inline function and avoids the need
to include fs.h in uio.h; _users_ of iov_iter_rw() obviously still need
fs.h, but such places always used to...