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Commit a82afdfc authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 0d03d59d

block/blk-core.c

+7 −12
Original line number Diff line number Diff line
@@ -1111,17 +1111,13 @@ void init_request_from_bio(struct request *req, struct bio *bio) 
	req->cmd_type = REQ_TYPE_FS;



	/*

	 * inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST)

	 * Inherit FAILFAST from bio (for read-ahead, and explicit

	 * FAILFAST).  FAILFAST flags are identical for req and bio.

	 */

	if (bio_rw_ahead(bio))

		req->cmd_flags |= (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |

				   REQ_FAILFAST_DRIVER);

	if (bio_failfast_dev(bio))

		req->cmd_flags |= REQ_FAILFAST_DEV;

	if (bio_failfast_transport(bio))

		req->cmd_flags |= REQ_FAILFAST_TRANSPORT;

	if (bio_failfast_driver(bio))

		req->cmd_flags |= REQ_FAILFAST_DRIVER;

		req->cmd_flags |= REQ_FAILFAST_MASK;

	else

		req->cmd_flags |= bio->bi_rw & REQ_FAILFAST_MASK;



	if (unlikely(bio_discard(bio))) {

		req->cmd_flags |= REQ_DISCARD;
@@ -2239,9 +2235,8 @@ EXPORT_SYMBOL(__blk_end_request_cur); 
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,

		     struct bio *bio)

{

	/* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw, and

	   we want BIO_RW_AHEAD (bit 1) to imply REQ_FAILFAST (bit 1). */

	rq->cmd_flags |= (bio->bi_rw & 3);

	/* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */

	rq->cmd_flags |= bio->bi_rw & REQ_RW;



	if (bio_has_data(bio)) {

		rq->nr_phys_segments = bio_phys_segments(q, bio);

include/linux/bio.h

+23 −20
Original line number Diff line number Diff line
@@ -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)))

include/linux/blkdev.h

+4 −0
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ enum rq_flag_bits { 
	__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 */

	/* above flags must match BIO_RW_* */

	__REQ_DISCARD,		/* request to discard sectors */

	__REQ_SORTED,		/* elevator knows about this request */

	__REQ_SOFTBARRIER,	/* may not be passed by ioscheduler */
@@ -143,6 +144,9 @@ enum rq_flag_bits { 
#define REQ_NOIDLE	(1 << __REQ_NOIDLE)

#define REQ_IO_STAT	(1 << __REQ_IO_STAT)



#define REQ_FAILFAST_MASK	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | \

				 REQ_FAILFAST_DRIVER)



#define BLK_MAX_CDB	16



/*