block: use the same failfast bits for bio and request

bio and request use the same set of failfast bits.  This patch makes
the following changes to simplify things.

* enumify BIO_RW* bits and reorder bits such that BIOS_RW_FAILFAST_*
  bits coincide with __REQ_FAILFAST_* bits.

* The above pushes BIO_RW_AHEAD out of sync with __REQ_FAILFAST_DEV
  but the matching is useless anyway.  init_request_from_bio() is
  responsible for setting FAILFAST bits on FS requests and non-FS
  requests never use BIO_RW_AHEAD.  Drop the code and comment from
  blk_rq_bio_prep().

* Define REQ_FAILFAST_MASK which is OR of all FAILFAST bits and
  simplify FAILFAST flags handling in init_request_from_bio().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Tejun Heo 2009-07-03 17:48:16 +09:00 committed by Jens Axboe
parent 0d03d59d9b
commit a82afdfcb8
3 changed files with 34 additions and 32 deletions

View file

@ -142,37 +142,40 @@ struct bio {
*
* bit 0 -- data direction
* If not set, bio is a read from device. If set, it's a write to device.
* bit 1 -- rw-ahead when set
* bit 2 -- barrier
* 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 3 -- synchronous I/O hint.
* bit 4 -- Unplug the device immediately after submitting this bio.
* bit 5 -- metadata request
* 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 6 -- discard sectors
* 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.
* bit 7 -- fail fast device errors
* bit 8 -- fail fast transport errors
* bit 9 -- fail fast driver errors
* 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.
*/
#define BIO_RW 0 /* Must match RW in req flags (blkdev.h) */
#define BIO_RW_AHEAD 1 /* Must match FAILFAST in req flags */
#define BIO_RW_BARRIER 2
#define BIO_RW_SYNCIO 3
#define BIO_RW_UNPLUG 4
#define BIO_RW_META 5
#define BIO_RW_DISCARD 6
#define BIO_RW_FAILFAST_DEV 7
#define BIO_RW_FAILFAST_TRANSPORT 8
#define BIO_RW_FAILFAST_DRIVER 9
#define BIO_RW_NOIDLE 10
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,
};
#define bio_rw_flagged(bio, flag) ((bio)->bi_rw & (1 << (flag)))