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authorChristoph Hellwig <hch@lst.de>2009-04-07 19:55:13 +0200
committerJens Axboe <jens.axboe@oracle.com>2009-04-15 08:28:09 +0200
commit8f3d8ba20e67991b531e9c0227dcd1f99271a32c (patch)
tree337efd46f067ce3b7eeab0c3627b02a7edef4afd /include
parent0882e8dd3aad33eca41696d463bb896e6c8817eb (diff)
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')
-rw-r--r--include/linux/bio.h109
1 files changed, 109 insertions, 0 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h
index b900d2c67d2..b89cf2d8289 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)]))