Ocfs2 devel - Mar 2015 - [RFC PATCH 1/5] new helper: iov_iter_rw()

Get either READ or WRITE out of iter->type.

Signed-off-by: Omar Sandoval <osandov at osandov.com>
---
 include/linux/uio.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 7188029..87a47b3 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -10,6 +10,7 @@
 #define __LINUX_UIO_H
 
 #include <linux/kernel.h>
+#include <linux/fs.h>
 #include <uapi/linux/uio.h>
 
 struct page;
@@ -111,6 +112,15 @@ static inline bool iter_is_iovec(struct iov_iter *i)
 }
 
 /*
+ * 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;
+}
+
+/*
  * Cap the iov_iter by given limit; note that the second argument is
  * *not* the new size - it's upper limit for such.  Passing it a value
  * greater than the amount of data in iov_iter is fine - it'll just do
-- 
2.3.3

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...