From d2044a94e80b61f68ee7456f82d9b443e9ff6ac7 Mon Sep 17 00:00:00 2001 From: Alasdair G Kergon Date: Wed, 22 Mar 2006 00:07:42 -0800 Subject: [PATCH] [PATCH] dm: bio split bvec fix The code that handles bios that span table target boundaries by breaking them up into smaller bios will not split an individual struct bio_vec into more than two pieces. Sometimes more than that are required. This patch adds a loop to break the second piece up into as many pieces as are necessary. Cc: "Abhishek Gupta" Cc: Dan Smith Signed-off-by: Alasdair G Kergon Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/dm.c | 43 ++++++++++++++++++++++++------------------- 1 file changed, 24 insertions(+), 19 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 88d60202b9db..26b08ee425c7 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -533,30 +533,35 @@ static void __clone_and_map(struct clone_info *ci) } else { /* - * Create two copy bios to deal with io that has - * been split across a target. + * Handle a bvec that must be split between two or more targets. */ struct bio_vec *bv = bio->bi_io_vec + ci->idx; + sector_t remaining = to_sector(bv->bv_len); + unsigned int offset = 0; - clone = split_bvec(bio, ci->sector, ci->idx, - bv->bv_offset, max); - __map_bio(ti, clone, tio); + do { + if (offset) { + ti = dm_table_find_target(ci->map, ci->sector); + max = max_io_len(ci->md, ci->sector, ti); - ci->sector += max; - ci->sector_count -= max; - ti = dm_table_find_target(ci->map, ci->sector); - - len = to_sector(bv->bv_len) - max; - clone = split_bvec(bio, ci->sector, ci->idx, - bv->bv_offset + to_bytes(max), len); - tio = alloc_tio(ci->md); - tio->io = ci->io; - tio->ti = ti; - memset(&tio->info, 0, sizeof(tio->info)); - __map_bio(ti, clone, tio); + tio = alloc_tio(ci->md); + tio->io = ci->io; + tio->ti = ti; + memset(&tio->info, 0, sizeof(tio->info)); + } + + len = min(remaining, max); + + clone = split_bvec(bio, ci->sector, ci->idx, + bv->bv_offset + offset, len); + + __map_bio(ti, clone, tio); + + ci->sector += len; + ci->sector_count -= len; + offset += to_bytes(len); + } while (remaining -= len); - ci->sector += len; - ci->sector_count -= len; ci->idx++; } } -- 2.30.2