bio, fs: separate out bio_types.h and define READ/WRITE constants in terms of BIO_RW_* flags

linux/fs.h hard coded READ/WRITE constants which should match BIO_RW_*
flags.  This is fragile and caused breakage during BIO_RW_* flag
rearrangement.  The hardcoding is to avoid include dependency hell.

Create linux/bio_types.h which contatins definitions for bio data
structures and flags and include it from bio.h and fs.h, and make fs.h
define all READ/WRITE related constants in terms of BIO_RW_* flags.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 7 insertions, 8 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 55dad7bca25b..c53911277210 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -8,6 +8,7 @@
 
 #include <linux/limits.h>
 #include <linux/ioctl.h>
+#include <linux/blk_types.h>
 
 /*
  * It's silly to have NR_OPEN bigger than NR_FILE, but you can change
@@ -117,7 +118,7 @@ struct inodes_stat_t {
  *                      immediately wait on this read without caring about
  *                      unplugging.
  * READA                Used for read-ahead operations. Lower priority, and the
- *                       block layer could (in theory) choose to ignore this
+ *                      block layer could (in theory) choose to ignore this
  *                      request if it runs into resource problems.
  * WRITE                A normal async write. Device will be plugged.
  * SWRITE               Like WRITE, but a special case for ll_rw_block() that
@@ -144,13 +145,13 @@ struct inodes_stat_t {
  *                      of this IO.
  *
  */
-#define RW_MASK                 1
-#define RWA_MASK                16
+#define RW_MASK                 REQ_WRITE
+#define RWA_MASK                REQ_RAHEAD
 
 #define READ                    0
-#define WRITE                   1
-#define READA                   16 /* readahead - don't block if no resources */
-#define SWRITE                  17 /* for ll_rw_block(), wait for buffer lock */
+#define WRITE                   RW_MASK
+#define READA                   RWA_MASK
+#define SWRITE                  (WRITE | READA)
 
 #define READ_SYNC               (READ | REQ_SYNC | REQ_UNPLUG)
 #define READ_META               (READ | REQ_META)
@@ -2200,7 +2201,6 @@ static inline void insert_inode_hash(struct inode *inode) {
 extern void file_move(struct file *f, struct list_head *list);
 extern void file_kill(struct file *f);
 #ifdef CONFIG_BLOCK
-struct bio;
 extern void submit_bio(int, struct bio *);
 extern int bdev_read_only(struct block_device *);
 #endif
@@ -2267,7 +2267,6 @@ static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
 #endif
 
 #ifdef CONFIG_BLOCK
-struct bio;
 typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode,
                             loff_t file_offset);
 void dio_end_io(struct bio *bio, int error);