[PATCH 05/10] block: Add bio_copy_data_iter(), zero_fill_bio_iter()

Kent Overstreet
2018-05-09T01:33:53Z

Add versions that take bvec_iter args instead of using bio->bi_iter - to
be used by bcachefs.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---
block/bio.c | 44 ++++++++++++++++++++++++--------------------
include/linux/bio.h | 18 +++++++++++++++---
2 files changed, 39 insertions(+), 23 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index b7cdad6fc4..d7bd765e9e 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -530,20 +530,20 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned int nr_iovecs,
}
EXPORT_SYMBOL(bio_alloc_bioset);

-void zero_fill_bio(struct bio *bio)
+void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start)
{
unsigned long flags;
struct bio_vec bv;
struct bvec_iter iter;

- bio_for_each_segment(bv, bio, iter) {
+ __bio_for_each_segment(bv, bio, iter, start) {
char *data = bvec_kmap_irq(&bv, &flags);
memset(data, 0, bv.bv_len);
flush_dcache_page(bv.bv_page);
bvec_kunmap_irq(data, &flags);
}
}
-EXPORT_SYMBOL(zero_fill_bio);
+EXPORT_SYMBOL(zero_fill_bio_iter);

/**
* bio_put - release a reference to a bio
@@ -971,28 +971,13 @@ void bio_advance(struct bio *bio, unsigned bytes)
}
EXPORT_SYMBOL(bio_advance);

-/**
- * bio_copy_data - copy contents of data buffers from one chain of bios to
- * another
- * @src: source bio list
- * @dst: destination bio list
- *
- * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
- * @src and @dst as linked lists of bios.
- *
- * Stops when it reaches the end of either @src or @dst - that is, copies
- * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
- */
-void bio_copy_data(struct bio *dst, struct bio *src)
+void bio_copy_data_iter(struct bio *dst, struct bvec_iter dst_iter,
+ struct bio *src, struct bvec_iter src_iter)
{
- struct bvec_iter src_iter, dst_iter;
struct bio_vec src_bv, dst_bv;
void *src_p, *dst_p;
unsigned bytes;

- src_iter = src->bi_iter;
- dst_iter = dst->bi_iter;
-
while (1) {
if (!src_iter.bi_size) {
src = src->bi_next;
@@ -1029,6 +1014,25 @@ void bio_copy_data(struct bio *dst, struct bio *src)
bio_advance_iter(dst, &dst_iter, bytes);
}
}
+EXPORT_SYMBOL(bio_copy_data_iter);
+
+/**
+ * bio_copy_data - copy contents of data buffers from one chain of bios to
+ * another
+ * @src: source bio list
+ * @dst: destination bio list
+ *
+ * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
+ * @src and @dst as linked lists of bios.
+ *
+ * Stops when it reaches the end of either @src or @dst - that is, copies
+ * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
+ */
+void bio_copy_data(struct bio *dst, struct bio *src)
+{
+ bio_copy_data_iter(dst, dst->bi_iter,
+ src, src->bi_iter);
+}
EXPORT_SYMBOL(bio_copy_data);

struct bio_map_data {
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 91b02520e2..5a6ee955a8 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -67,8 +67,12 @@

#define bio_multiple_segments(bio) \
((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
-#define bio_sectors(bio) ((bio)->bi_iter.bi_size >> 9)
-#define bio_end_sector(bio) ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
+
+#define bvec_iter_sectors(iter) ((iter).bi_size >> 9)
+#define bvec_iter_end_sector(iter) ((iter).bi_sector + bvec_iter_sectors((iter)))
+
+#define bio_sectors(bio) bvec_iter_sectors((bio)->bi_iter)
+#define bio_end_sector(bio) bvec_iter_end_sector((bio)->bi_iter)

/*
* Return the data direction, READ or WRITE.
@@ -501,6 +505,8 @@ static inline void bio_flush_dcache_pages(struct bio *bi)
}
#endif

+extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter dst_iter,
+ struct bio *src, struct bvec_iter src_iter);
extern void bio_copy_data(struct bio *dst, struct bio *src);
extern void bio_free_pages(struct bio *bio);

@@ -509,7 +515,13 @@ extern struct bio *bio_copy_user_iov(struct request_queue *,
struct iov_iter *,
gfp_t);
extern int bio_uncopy_user(struct bio *);
-void zero_fill_bio(struct bio *bio);
+void zero_fill_bio_iter(struct bio *bio, struct bvec_iter iter);
+
+static inline void zero_fill_bio(struct bio *bio)
+{
+ zero_fill_bio_iter(bio, bio->bi_iter);
+}
+
extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
extern unsigned int bvec_nr_vecs(unsigned short idx);
--
2.17.0