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, 193 insertions, 0 deletions

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
new file mode 100644
index 00000000000..118523734af
--- /dev/null
+++ b/include/linux/blk_types.h
@@ -0,0 +1,193 @@
+/*
+ * Block data types and constants.  Directly include this file only to
+ * break include dependency loop.
+ */
+#ifndef __LINUX_BLK_TYPES_H
+#define __LINUX_BLK_TYPES_H
+
+#ifdef CONFIG_BLOCK
+
+#include <linux/types.h>
+
+struct bio_set;
+struct bio;
+struct bio_integrity_payload;
+struct page;
+struct block_device;
+typedef void (bio_end_io_t) (struct bio *, int);
+typedef void (bio_destructor_t) (struct bio *);
+
+/*
+ * was unsigned short, but we might as well be ready for > 64kB I/O pages
+ */
+struct bio_vec {
+	struct page	*bv_page;
+	unsigned int	bv_len;
+	unsigned int	bv_offset;
+};
+
+/*
+ * main unit of I/O for the block layer and lower layers (ie drivers and
+ * stacking drivers)
+ */
+struct bio {
+	sector_t		bi_sector;	/* device address in 512 byte
+						   sectors */
+	struct bio		*bi_next;	/* request queue link */
+	struct block_device	*bi_bdev;
+	unsigned long		bi_flags;	/* status, command, etc */
+	unsigned long		bi_rw;		/* bottom bits READ/WRITE,
+						 * top bits priority
+						 */
+
+	unsigned short		bi_vcnt;	/* how many bio_vec's */
+	unsigned short		bi_idx;		/* current index into bvl_vec */
+
+	/* Number of segments in this BIO after
+	 * physical address coalescing is performed.
+	 */
+	unsigned int		bi_phys_segments;
+
+	unsigned int		bi_size;	/* residual I/O count */
+
+	/*
+	 * To keep track of the max segment size, we account for the
+	 * sizes of the first and last mergeable segments in this bio.
+	 */
+	unsigned int		bi_seg_front_size;
+	unsigned int		bi_seg_back_size;
+
+	unsigned int		bi_max_vecs;	/* max bvl_vecs we can hold */
+
+	unsigned int		bi_comp_cpu;	/* completion CPU */
+
+	atomic_t		bi_cnt;		/* pin count */
+
+	struct bio_vec		*bi_io_vec;	/* the actual vec list */
+
+	bio_end_io_t		*bi_end_io;
+
+	void			*bi_private;
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+	struct bio_integrity_payload *bi_integrity;  /* data integrity */
+#endif
+
+	bio_destructor_t	*bi_destructor;	/* destructor */
+
+	/*
+	 * We can inline a number of vecs at the end of the bio, to avoid
+	 * double allocations for a small number of bio_vecs. This member
+	 * MUST obviously be kept at the very end of the bio.
+	 */
+	struct bio_vec		bi_inline_vecs[0];
+};
+
+/*
+ * bio flags
+ */
+#define BIO_UPTODATE	0	/* ok after I/O completion */
+#define BIO_RW_BLOCK	1	/* RW_AHEAD set, and read/write would block */
+#define BIO_EOF		2	/* out-out-bounds error */
+#define BIO_SEG_VALID	3	/* bi_phys_segments valid */
+#define BIO_CLONED	4	/* doesn't own data */
+#define BIO_BOUNCED	5	/* bio is a bounce bio */
+#define BIO_USER_MAPPED 6	/* contains user pages */
+#define BIO_EOPNOTSUPP	7	/* not supported */
+#define BIO_CPU_AFFINE	8	/* complete bio on same CPU as submitted */
+#define BIO_NULL_MAPPED 9	/* contains invalid user pages */
+#define BIO_FS_INTEGRITY 10	/* fs owns integrity data, not block layer */
+#define BIO_QUIET	11	/* Make BIO Quiet */
+#define bio_flagged(bio, flag)	((bio)->bi_flags & (1 << (flag)))
+
+/*
+ * top 4 bits of bio flags indicate the pool this bio came from
+ */
+#define BIO_POOL_BITS		(4)
+#define BIO_POOL_NONE		((1UL << BIO_POOL_BITS) - 1)
+#define BIO_POOL_OFFSET		(BITS_PER_LONG - BIO_POOL_BITS)
+#define BIO_POOL_MASK		(1UL << BIO_POOL_OFFSET)
+#define BIO_POOL_IDX(bio)	((bio)->bi_flags >> BIO_POOL_OFFSET)
+
+/*
+ * Request flags.  For use in the cmd_flags field of struct request, and in
+ * bi_rw of struct bio.  Note that some flags are only valid in either one.
+ */
+enum rq_flag_bits {
+	/* common flags */
+	__REQ_WRITE,		/* not set, read. set, write */
+	__REQ_FAILFAST_DEV,	/* no driver retries of device errors */
+	__REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
+	__REQ_FAILFAST_DRIVER,	/* no driver retries of driver errors */
+
+	__REQ_HARDBARRIER,	/* may not be passed by drive either */
+	__REQ_SYNC,		/* request is sync (sync write or read) */
+	__REQ_META,		/* metadata io request */
+	__REQ_DISCARD,		/* request to discard sectors */
+	__REQ_NOIDLE,		/* don't anticipate more IO after this one */
+
+	/* bio only flags */
+	__REQ_UNPLUG,		/* unplug the immediately after submission */
+	__REQ_RAHEAD,		/* read ahead, can fail anytime */
+
+	/* request only flags */
+	__REQ_SORTED,		/* elevator knows about this request */
+	__REQ_SOFTBARRIER,	/* may not be passed by ioscheduler */
+	__REQ_FUA,		/* forced unit access */
+	__REQ_NOMERGE,		/* don't touch this for merging */
+	__REQ_STARTED,		/* drive already may have started this one */
+	__REQ_DONTPREP,		/* don't call prep for this one */
+	__REQ_QUEUED,		/* uses queueing */
+	__REQ_ELVPRIV,		/* elevator private data attached */
+	__REQ_FAILED,		/* set if the request failed */
+	__REQ_QUIET,		/* don't worry about errors */
+	__REQ_PREEMPT,		/* set for "ide_preempt" requests */
+	__REQ_ORDERED_COLOR,	/* is before or after barrier */
+	__REQ_ALLOCED,		/* request came from our alloc pool */
+	__REQ_COPY_USER,	/* contains copies of user pages */
+	__REQ_INTEGRITY,	/* integrity metadata has been remapped */
+	__REQ_FLUSH,		/* request for cache flush */
+	__REQ_IO_STAT,		/* account I/O stat */
+	__REQ_MIXED_MERGE,	/* merge of different types, fail separately */
+	__REQ_NR_BITS,		/* stops here */
+};
+
+#define REQ_WRITE		(1 << __REQ_WRITE)
+#define REQ_FAILFAST_DEV	(1 << __REQ_FAILFAST_DEV)
+#define REQ_FAILFAST_TRANSPORT	(1 << __REQ_FAILFAST_TRANSPORT)
+#define REQ_FAILFAST_DRIVER	(1 << __REQ_FAILFAST_DRIVER)
+#define REQ_HARDBARRIER		(1 << __REQ_HARDBARRIER)
+#define REQ_SYNC		(1 << __REQ_SYNC)
+#define REQ_META		(1 << __REQ_META)
+#define REQ_DISCARD		(1 << __REQ_DISCARD)
+#define REQ_NOIDLE		(1 << __REQ_NOIDLE)
+
+#define REQ_FAILFAST_MASK \
+	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
+#define REQ_COMMON_MASK \
+	(REQ_WRITE | REQ_FAILFAST_MASK | REQ_HARDBARRIER | REQ_SYNC | \
+	 REQ_META| REQ_DISCARD | REQ_NOIDLE)
+
+#define REQ_UNPLUG		(1 << __REQ_UNPLUG)
+#define REQ_RAHEAD		(1 << __REQ_RAHEAD)
+
+#define REQ_SORTED		(1 << __REQ_SORTED)
+#define REQ_SOFTBARRIER		(1 << __REQ_SOFTBARRIER)
+#define REQ_FUA			(1 << __REQ_FUA)
+#define REQ_NOMERGE		(1 << __REQ_NOMERGE)
+#define REQ_STARTED		(1 << __REQ_STARTED)
+#define REQ_DONTPREP		(1 << __REQ_DONTPREP)
+#define REQ_QUEUED		(1 << __REQ_QUEUED)
+#define REQ_ELVPRIV		(1 << __REQ_ELVPRIV)
+#define REQ_FAILED		(1 << __REQ_FAILED)
+#define REQ_QUIET		(1 << __REQ_QUIET)
+#define REQ_PREEMPT		(1 << __REQ_PREEMPT)
+#define REQ_ORDERED_COLOR	(1 << __REQ_ORDERED_COLOR)
+#define REQ_ALLOCED		(1 << __REQ_ALLOCED)
+#define REQ_COPY_USER		(1 << __REQ_COPY_USER)
+#define REQ_INTEGRITY		(1 << __REQ_INTEGRITY)
+#define REQ_FLUSH		(1 << __REQ_FLUSH)
+#define REQ_IO_STAT		(1 << __REQ_IO_STAT)
+#define REQ_MIXED_MERGE		(1 << __REQ_MIXED_MERGE)
+
+#endif /* CONFIG_BLOCK */
+#endif /* __LINUX_BLK_TYPES_H */