From 4550dd6c6b062fc5e5b647296d55da22616123c3 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Wed, 7 Aug 2013 14:26:21 -0700 Subject: block: Immutable bio vecs This adds a mechanism by which we can advance a bio by an arbitrary number of bytes without modifying the biovec: bio->bi_iter.bi_bvec_done indicates the number of bytes completed in the current bvec. Various driver code still needs to be updated to not refer to the bvec directly before we can use this for interesting things, like efficient bio splitting. Signed-off-by: Kent Overstreet Cc: Jens Axboe Cc: Lars Ellenberg Cc: Paul Clements Cc: drbd-user@lists.linbit.com Cc: nbd-general@lists.sourceforge.net --- fs/bio.c | 27 ++------------------------- 1 file changed, 2 insertions(+), 25 deletions(-) (limited to 'fs/bio.c') diff --git a/fs/bio.c b/fs/bio.c index 8b7f14a95503..07b4b7afa695 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -532,13 +532,11 @@ void __bio_clone(struct bio *bio, struct bio *bio_src) * most users will be overriding ->bi_bdev with a new target, * so we don't set nor calculate new physical/hw segment counts here */ - bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector; bio->bi_bdev = bio_src->bi_bdev; bio->bi_flags |= 1 << BIO_CLONED; bio->bi_rw = bio_src->bi_rw; bio->bi_vcnt = bio_src->bi_vcnt; - bio->bi_iter.bi_size = bio_src->bi_iter.bi_size; - bio->bi_iter.bi_idx = bio_src->bi_iter.bi_idx; + bio->bi_iter = bio_src->bi_iter; } EXPORT_SYMBOL(__bio_clone); @@ -808,28 +806,7 @@ void bio_advance(struct bio *bio, unsigned bytes) if (bio_integrity(bio)) bio_integrity_advance(bio, bytes); - bio->bi_iter.bi_sector += bytes >> 9; - bio->bi_iter.bi_size -= bytes; - - if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK) - return; - - while (bytes) { - if (unlikely(bio->bi_iter.bi_idx >= bio->bi_vcnt)) { - WARN_ONCE(1, "bio idx %d >= vcnt %d\n", - bio->bi_iter.bi_idx, bio->bi_vcnt); - break; - } - - if (bytes >= bio_iovec(bio).bv_len) { - bytes -= bio_iovec(bio).bv_len; - bio->bi_iter.bi_idx++; - } else { - bio_iovec(bio).bv_len -= bytes; - bio_iovec(bio).bv_offset += bytes; - bytes = 0; - } - } + bio_advance_iter(bio, &bio->bi_iter, bytes); } EXPORT_SYMBOL(bio_advance); -- cgit v1.2.3