From bf2de6f5a4faf0197268f18d08969b003b87b6e8 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 27 Sep 2007 13:01:25 +0200 Subject: block: Initial support for data-less (or empty) barrier support This implements functionality to pass down or insert a barrier in a queue, without having data attached to it. The ->prepare_flush_fn() infrastructure from data barriers are reused to provide this functionality. Signed-off-by: Jens Axboe --- include/linux/bio.h | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) (limited to 'include/linux/bio.h') diff --git a/include/linux/bio.h b/include/linux/bio.h index 089a8bc55dd4..4da441337d6e 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -176,13 +176,28 @@ struct bio { #define bio_offset(bio) bio_iovec((bio))->bv_offset #define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_idx) #define bio_sectors(bio) ((bio)->bi_size >> 9) -#define bio_cur_sectors(bio) (bio_iovec(bio)->bv_len >> 9) -#define bio_data(bio) (page_address(bio_page((bio))) + bio_offset((bio))) #define bio_barrier(bio) ((bio)->bi_rw & (1 << BIO_RW_BARRIER)) #define bio_sync(bio) ((bio)->bi_rw & (1 << BIO_RW_SYNC)) #define bio_failfast(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST)) #define bio_rw_ahead(bio) ((bio)->bi_rw & (1 << BIO_RW_AHEAD)) #define bio_rw_meta(bio) ((bio)->bi_rw & (1 << BIO_RW_META)) +#define bio_empty_barrier(bio) (bio_barrier(bio) && !(bio)->bi_size) + +static inline unsigned int bio_cur_sectors(struct bio *bio) +{ + if (bio->bi_vcnt) + return bio_iovec(bio)->bv_len >> 9; + + return 0; +} + +static inline void *bio_data(struct bio *bio) +{ + if (bio->bi_vcnt) + return page_address(bio_page(bio)) + bio_offset(bio); + + return NULL; +} /* * will die -- cgit v1.2.3