From f79ea4161434b31e351658283b24e92c3e570142 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Thu, 20 Sep 2012 16:38:30 -0700 Subject: [PATCH] block: Refactor blk_update_request() Converts it to use bio_advance(), simplifying it quite a bit in the process. Note that req_bio_endio() now always calls bio_advance() - which means it always loops over the biovec, not just on partial completions. Don't expect it to affect performance, but worth noting. Tested it by forcing partial updates, and dumping before and after on various bio/bvec fields when doing a partial update. Signed-off-by: Kent Overstreet CC: Jens Axboe --- block/blk-core.c | 80 +++++++++----------------------------------------------- 1 file changed, 12 insertions(+), 68 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 074b758..86a1afe 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -158,20 +158,10 @@ static void req_bio_endio(struct request *rq, struct bio *bio, else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) error = -EIO; - if (unlikely(nbytes > bio->bi_size)) { - printk(KERN_ERR "%s: want %u bytes done, %u left\n", - __func__, nbytes, bio->bi_size); - nbytes = bio->bi_size; - } - if (unlikely(rq->cmd_flags & REQ_QUIET)) set_bit(BIO_QUIET, &bio->bi_flags); - bio->bi_size -= nbytes; - bio->bi_sector += (nbytes >> 9); - - if (bio_integrity(bio)) - bio_integrity_advance(bio, nbytes); + bio_advance(bio, nbytes); /* don't actually finish bio if it's part of flush sequence */ if (bio->bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ)) @@ -2252,8 +2242,7 @@ EXPORT_SYMBOL(blk_fetch_request); **/ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) { - int total_bytes, bio_nbytes, next_idx = 0; - struct bio *bio; + int total_bytes; if (!req->bio) return false; @@ -2299,56 +2288,21 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) blk_account_io_completion(req, nr_bytes); - total_bytes = bio_nbytes = 0; - while ((bio = req->bio) != NULL) { - int nbytes; + total_bytes = 0; + while (req->bio) { + struct bio *bio = req->bio; + unsigned bio_bytes = min(bio->bi_size, nr_bytes); - if (nr_bytes >= bio->bi_size) { + if (bio_bytes == bio->bi_size) req->bio = bio->bi_next; - nbytes = bio->bi_size; - req_bio_endio(req, bio, nbytes, error); - next_idx = 0; - bio_nbytes = 0; - } else { - int idx = bio->bi_idx + next_idx; - - if (unlikely(idx >= bio->bi_vcnt)) { - blk_dump_rq_flags(req, "__end_that"); - printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n", - __func__, idx, bio->bi_vcnt); - break; - } - - nbytes = bio_iovec_idx(bio, idx)->bv_len; - BIO_BUG_ON(nbytes > bio->bi_size); - - /* - * not a complete bvec done - */ - if (unlikely(nbytes > nr_bytes)) { - bio_nbytes += nr_bytes; - total_bytes += nr_bytes; - break; - } - /* - * advance to the next vector - */ - next_idx++; - bio_nbytes += nbytes; - } + req_bio_endio(req, bio, bio_bytes, error); - total_bytes += nbytes; - nr_bytes -= nbytes; + total_bytes += bio_bytes; + nr_bytes -= bio_bytes; - bio = req->bio; - if (bio) { - /* - * end more in this run, or just return 'not-done' - */ - if (unlikely(nr_bytes <= 0)) - break; - } + if (!nr_bytes) + break; } /* @@ -2364,16 +2318,6 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) return false; } - /* - * if the request wasn't completed, update state - */ - if (bio_nbytes) { - req_bio_endio(req, bio, bio_nbytes, error); - bio->bi_idx += next_idx; - bio_iovec(bio)->bv_offset += nr_bytes; - bio_iovec(bio)->bv_len -= nr_bytes; - } - req->__data_len -= total_bytes; req->buffer = bio_data(req->bio); -- 2.7.4