From a82afdfcb8c0df09776b6458af6b68fc58b2e87b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 3 Jul 2009 17:48:16 +0900 Subject: [PATCH] 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 Signed-off-by: Jens Axboe --- block/blk-core.c | 19 +++++++------------ include/linux/bio.h | 43 ++++++++++++++++++++++-------------------- include/linux/blkdev.h | 4 ++++ 3 files changed, 34 insertions(+), 32 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index e3299a77a0d..4daae1ee2b2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -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); diff --git a/include/linux/bio.h b/include/linux/bio.h index 2892b710771..a299ed38fcd 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -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))) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 69103e053c9..c3015736d81 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -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 /* -- 2.41.0