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Go Back   Linux Archive > Redhat > Device-mapper Development

 
 
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Old 08-02-2010, 02:13 PM
Tejun Heo
 
Default 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>
Cc: Jens Axobe <axboe@kernel.dk>
---
include/linux/bio.h | 153 +-----------------------------------------
include/linux/bio_types.h | 164 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 17 ++--
3 files changed, 176 insertions(+), 158 deletions(-)

Index: work/include/linux/bio.h
================================================== =================
--- work.orig/include/linux/bio.h
+++ work/include/linux/bio.h
@@ -9,7 +9,7 @@
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
-
+ *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
@@ -28,6 +28,9 @@

#include <asm/io.h>

+/* struct bio, bio_vec and BIO_* flags are defined in bio_types.h */
+#include <linux/bio_types.h>
+
#define BIO_DEBUG

#ifdef BIO_DEBUG
@@ -41,154 +44,6 @@
#define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)

/*
- * 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;
-};
-
-struct bio_set;
-struct bio;
-struct bio_integrity_payload;
-typedef void (bio_end_io_t) (struct bio *, int);
-typedef void (bio_destructor_t) (struct bio *);
-
-/*
- * 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)
-
-/*
- * bio bi_rw flags
- *
- * bit 0 -- data direction
- * If not set, bio is a read from device. If set, it's a write to device.
- * bit 1 -- fail fast device errors
- * bit 2 -- fail fast transport errors
- * bit 3 -- fail fast driver errors
- * bit 4 -- rw-ahead when set
- * bit 5 -- barrier
- * Insert a serialization point in the IO queue, forcing previously
- * submitted IO to be completed before this one is issued.
- * bit 6 -- synchronous I/O hint.
- * bit 7 -- Unplug the device immediately after submitting this bio.
- * bit 8 -- metadata request
- * Used for tracing to differentiate metadata and data IO. May also
- * get some preferential treatment in the IO scheduler
- * bit 9 -- discard sectors
- * Informs the lower level device that this range of sectors is no longer
- * used by the file system and may thus be freed by the device. Used
- * for flash based storage.
- * Don't want driver retries for any fast fail whatever the reason.
- * bit 10 -- Tell the IO scheduler not to wait for more requests after this
- one has been submitted, even if it is a SYNC request.
- */
-enum bio_rw_flags {
- BIO_RW,
- BIO_RW_FAILFAST_DEV,
- BIO_RW_FAILFAST_TRANSPORT,
- BIO_RW_FAILFAST_DRIVER,
- /* above flags must match REQ_* */
- BIO_RW_AHEAD,
- BIO_RW_BARRIER,
- BIO_RW_SYNCIO,
- BIO_RW_UNPLUG,
- BIO_RW_META,
- BIO_RW_DISCARD,
- BIO_RW_NOIDLE,
-};
-
-/*
- * First four bits must match between bio->bi_rw and rq->cmd_flags, make
- * that explicit here.
- */
-#define BIO_RW_RQ_MASK 0xf
-
-static inline bool bio_rw_flagged(struct bio *bio, enum bio_rw_flags flag)
-{
- return (bio->bi_rw & (1 << flag)) != 0;
-}
-
-/*
* upper 16 bits of bi_rw define the io priority of this bio
*/
#define BIO_PRIO_SHIFT (8 * sizeof(unsigned long) - IOPRIO_BITS)
Index: work/include/linux/bio_types.h
================================================== =================
--- /dev/null
+++ work/include/linux/bio_types.h
@@ -0,0 +1,164 @@
+/*
+ * BIO data types and constants. Include linux/bio.h for usual cases.
+ * Directly include this file only to break include dependency loop.
+ */
+#ifndef __LINUX_BIO_TYPES_H
+#define __LINUX_BIO_TYPES_H
+
+#ifdef CONFIG_BLOCK
+
+#include <linux/types.h>
+
+struct bio_set;
+struct bio;
+struct bio_integrity_payload;
+struct page;
+struct block_device;
+
+/*
+ * 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;
+};
+
+typedef void (bio_end_io_t) (struct bio *, int);
+typedef void (bio_destructor_t) (struct bio *);
+
+/*
+ * 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)
+
+/*
+ * bio bi_rw flags
+ *
+ * bit 0 -- data direction
+ * If not set, bio is a read from device. If set, it's a write to device.
+ * bit 1 -- fail fast device errors
+ * bit 2 -- fail fast transport errors
+ * bit 3 -- fail fast driver errors
+ * bit 4 -- rw-ahead when set
+ * bit 5 -- barrier
+ * Insert a serialization point in the IO queue, forcing previously
+ * submitted IO to be completed before this one is issued.
+ * bit 6 -- synchronous I/O hint.
+ * bit 7 -- Unplug the device immediately after submitting this bio.
+ * bit 8 -- metadata request
+ * Used for tracing to differentiate metadata and data IO. May also
+ * get some preferential treatment in the IO scheduler
+ * bit 9 -- discard sectors
+ * Informs the lower level device that this range of sectors is no longer
+ * used by the file system and may thus be freed by the device. Used
+ * for flash based storage.
+ * Don't want driver retries for any fast fail whatever the reason.
+ * bit 10 -- Tell the IO scheduler not to wait for more requests after this
+ one has been submitted, even if it is a SYNC request.
+ */
+enum bio_rw_flags {
+ BIO_RW,
+ BIO_RW_FAILFAST_DEV,
+ BIO_RW_FAILFAST_TRANSPORT,
+ BIO_RW_FAILFAST_DRIVER,
+ /* above flags must match REQ_* */
+ BIO_RW_AHEAD,
+ BIO_RW_BARRIER,
+ BIO_RW_SYNCIO,
+ BIO_RW_UNPLUG,
+ BIO_RW_META,
+ BIO_RW_DISCARD,
+ BIO_RW_NOIDLE,
+};
+
+/*
+ * First four bits must match between bio->bi_rw and rq->cmd_flags, make
+ * that explicit here.
+ */
+#define BIO_RW_RQ_MASK 0xf
+
+static inline bool bio_rw_flagged(struct bio *bio, enum bio_rw_flags flag)
+{
+ return (bio->bi_rw & (1 << flag)) != 0;
+}
+
+#endif /* CONFIG_BLOCK */
+#endif /* __LINUX_BIO_TYPES_H */
Index: work/include/linux/fs.h
================================================== =================
--- work.orig/include/linux/fs.h
+++ work/include/linux/fs.h
@@ -8,6 +8,7 @@

#include <linux/limits.h>
#include <linux/ioctl.h>
+#include <linux/bio_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
@@ -144,12 +145,12 @@ struct inodes_stat_t {
* of this IO.
*
*/
-#define RW_MASK 1
-#define RWA_MASK 2
-#define READ 0
-#define WRITE 1
-#define READA 16 /* read-ahead - don't block if no resources */
-#define SWRITE 17 /* for ll_rw_block() - wait for buffer lock */
+#define RW_MASK (1 << BIO_RW)
+#define RWA_MASK (1 << BIO_RW_AHEAD)
+#define READ 0
+#define WRITE RW_MASK
+#define READA RWA_MASK
+#define SWRITE (WRITE | READA)
#define READ_SYNC (READ | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG))
#define READ_META (READ | (1 << BIO_RW_META))
#define WRITE_SYNC_PLUG (WRITE | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_NOIDLE))
@@ -2198,7 +2199,6 @@ static inline void insert_inode_hash(str
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
@@ -2265,7 +2265,6 @@ static inline int xip_truncate_page(stru
#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);

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