This abstracts out a way to reuse a bio without destroying the
data pointers.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/bio.c | 20 ++++++++++++++++++++
include/linux/bio.h | 1 +
2 files changed, 21 insertions(+)
diff --git a/block/bio.c b/block/bio.c
index 70c4e1b6dd45..fa1b7ab50784 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -308,6 +308,26 @@ void bio_reset(struct bio *bio)
}
EXPORT_SYMBOL(bio_reset);
+/**
+ * bio_reuse - prepare a bio for reuse
+ * @bio: bio to reuse
+ *
+ * Prepares an already setup and possible used bio for reusing it another
+ * time. Compared to bio_reset() this preserves the bio size and the
+ * layout and contents of the bio vectors.
+ */
+void bio_reuse(struct bio *bio)
+{
+ unsigned int size = bio->bi_iter.bi_size;
+ unsigned short vcnt = bio->bi_vcnt;
+
+ bio_reset(bio);
+
+ bio->bi_iter.bi_size = size;
+ bio->bi_vcnt = vcnt;
+}
+EXPORT_SYMBOL_GPL(bio_reuse);
+
static struct bio *__bio_chain_endio(struct bio *bio)
{
struct bio *parent = bio->bi_private;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index f08f5fe7bd08..15c871ab50db 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -475,6 +475,7 @@ extern void bio_init(struct bio *bio, struct bio_vec *table,
unsigned short max_vecs);
extern void bio_uninit(struct bio *);
extern void bio_reset(struct bio *);
+void bio_reuse(struct bio *);
void bio_chain(struct bio *, struct bio *);
extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
--
2.17.1
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