fs: decouple READ and WRITE from the block layer ops

Move READ and WRITE to kernel.h and don't define them in terms of block
layer ops; they are our generic data direction indicators these days
and have no more resemblance with the block layer ops.

Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

include/linux/bio.h

···
 #define bio_end_sector(bio)	((bio)->bi_iter.bi_sector + bio_sectors((bio)))
 
 /*
+ * Return the data direction, READ or WRITE.
+ */
+#define bio_data_dir(bio) \
+	(op_is_write(bio_op(bio)) ? WRITE : READ)
+
+/*
  * Check whether this bio carries any data or not. A NULL bio is allowed.
  */
 static inline bool bio_has_data(struct bio *bio)

include/linux/fs.h

···
  */
 #define CHECK_IOVEC_ONLY -1
 
-#define RW_MASK			REQ_OP_WRITE
-
-#define READ			REQ_OP_READ
-#define WRITE			REQ_OP_WRITE
-
 /*
  * Attribute flags.  These should be or-ed together to figure out what
  * has been changed!
···
 extern bool is_bad_inode(struct inode *);
 
 #ifdef CONFIG_BLOCK
-/*
- * return data direction, READ or WRITE
- */
-static inline int bio_data_dir(struct bio *bio)
-{
-	return op_is_write(bio_op(bio)) ? WRITE : READ;
-}
-
 extern void check_disk_size_change(struct gendisk *disk,
 				   struct block_device *bdev);
 extern int revalidate_disk(struct gendisk *);

include/linux/kernel.h

···
 #define PTR_ALIGN(p, a)		((typeof(p))ALIGN((unsigned long)(p), (a)))
 #define IS_ALIGNED(x, a)		(((x) & ((typeof(x))(a) - 1)) == 0)
 
+/* generic data direction definitions */
+#define READ			0
+#define WRITE			1
+
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
 
 #define u64_to_user_ptr(x) (		\

include/linux/uio.h

···
  *
  * The ?: is just for type safety.
  */
-#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & RW_MASK)
+#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & (READ | WRITE))
 
 /*
  * Cap the iov_iter by given limit; note that the second argument is