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| author | David Woodhouse <David.Woodhouse@intel.com> | 2008-08-09 16:22:17 +0100 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 08:56:01 +0200 |
| commit | d628eaef310533767ce68664873869c2d7f78f09 (patch) | |
| tree | 12d6a9e6db000d89deb7ab01d55d2e7b9e6f42c5 | |
| parent | 36144077bce9f89763ce994bc631cbd1c9db7785 (diff) | |
| download | lwn-d628eaef310533767ce68664873869c2d7f78f09.tar.gz lwn-d628eaef310533767ce68664873869c2d7f78f09.zip | |
Fix up comments about matching flags between bio and rq
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| -rw-r--r-- | block/blk-core.c | 7 | ||||
| -rw-r--r-- | include/linux/bio.h | 4 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 2 |
3 files changed, 5 insertions, 8 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index b5776c1fd52a..a496727df7ef 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -624,10 +624,6 @@ blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask) blk_rq_init(q, rq); - /* - * first three bits are identical in rq->cmd_flags and bio->bi_rw, - * see bio.h and blkdev.h - */ rq->cmd_flags = rw | REQ_ALLOCED; if (priv) { @@ -2012,7 +2008,8 @@ EXPORT_SYMBOL_GPL(blk_end_request_callback); void blk_rq_bio_prep(struct request_queue *q, struct request *rq, struct bio *bio) { - /* first two bits are identical in rq->cmd_flags and bio->bi_rw */ + /* 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); rq->nr_phys_segments = bio_phys_segments(q, bio); diff --git a/include/linux/bio.h b/include/linux/bio.h index dbeb66f813ab..17f1fbdb31bf 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -150,8 +150,8 @@ struct bio { * bit 3 -- fail fast, don't want low level driver retries * bit 4 -- synchronous I/O hint: the block layer will unplug immediately */ -#define BIO_RW 0 -#define BIO_RW_AHEAD 1 +#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_FAILFAST 3 #define BIO_RW_SYNC 4 diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 53ea933cf60b..e0ba018f5e88 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -84,7 +84,7 @@ enum { }; /* - * request type modified bits. first three bits match BIO_RW* bits, important + * request type modified bits. first two bits match BIO_RW* bits, important */ enum rq_flag_bits { __REQ_RW, /* not set, read. set, write */ |