diff options
author | Christoph Hellwig <hch@lst.de> | 2009-04-07 19:55:13 +0200 |
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committer | Jens Axboe <jens.axboe@oracle.com> | 2009-04-15 08:28:09 +0200 |
commit | 8f3d8ba20e67991b531e9c0227dcd1f99271a32c (patch) | |
tree | 337efd46f067ce3b7eeab0c3627b02a7edef4afd /include/linux/bio.h | |
parent | 0882e8dd3aad33eca41696d463bb896e6c8817eb (diff) | |
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block: move bio list helpers into bio.h
It's used by DM and MD and generally useful, so move the bio list
helpers into bio.h.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'include/linux/bio.h')
-rw-r--r-- | include/linux/bio.h | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h index b900d2c6..b89cf2d 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -504,6 +504,115 @@ static inline int bio_has_data(struct bio *bio) return bio && bio->bi_io_vec != NULL; } +/* + * BIO list managment for use by remapping drivers (e.g. DM or MD). + * + * A bio_list anchors a singly-linked list of bios chained through the bi_next + * member of the bio. The bio_list also caches the last list member to allow + * fast access to the tail. + */ +struct bio_list { + struct bio *head; + struct bio *tail; +}; + +static inline int bio_list_empty(const struct bio_list *bl) +{ + return bl->head == NULL; +} + +static inline void bio_list_init(struct bio_list *bl) +{ + bl->head = bl->tail = NULL; +} + +#define bio_list_for_each(bio, bl) \ + for (bio = (bl)->head; bio; bio = bio->bi_next) + +static inline unsigned bio_list_size(const struct bio_list *bl) +{ + unsigned sz = 0; + struct bio *bio; + + bio_list_for_each(bio, bl) + sz++; + + return sz; +} + +static inline void bio_list_add(struct bio_list *bl, struct bio *bio) +{ + bio->bi_next = NULL; + + if (bl->tail) + bl->tail->bi_next = bio; + else + bl->head = bio; + + bl->tail = bio; +} + +static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio) +{ + bio->bi_next = bl->head; + + bl->head = bio; + + if (!bl->tail) + bl->tail = bio; +} + +static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2) +{ + if (!bl2->head) + return; + + if (bl->tail) + bl->tail->bi_next = bl2->head; + else + bl->head = bl2->head; + + bl->tail = bl2->tail; +} + +static inline void bio_list_merge_head(struct bio_list *bl, + struct bio_list *bl2) +{ + if (!bl2->head) + return; + + if (bl->head) + bl2->tail->bi_next = bl->head; + else + bl->tail = bl2->tail; + + bl->head = bl2->head; +} + +static inline struct bio *bio_list_pop(struct bio_list *bl) +{ + struct bio *bio = bl->head; + + if (bio) { + bl->head = bl->head->bi_next; + if (!bl->head) + bl->tail = NULL; + + bio->bi_next = NULL; + } + + return bio; +} + +static inline struct bio *bio_list_get(struct bio_list *bl) +{ + struct bio *bio = bl->head; + + bl->head = bl->tail = NULL; + + return bio; +} + #if defined(CONFIG_BLK_DEV_INTEGRITY) #define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)])) |