-stable review patch. If anyone has any objections, please let us know.
------------------
From: Alasdair G Kergon <[email protected]>
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" <[email protected]>
Cc: Dan Smith <[email protected]>
Signed-off-by: Alasdair G Kergon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/md/dm.c | 45 +++++++++++++++++++++++++--------------------
1 file changed, 25 insertions(+), 20 deletions(-)
--- linux-2.6.16.orig/drivers/md/dm.c
+++ linux-2.6.16/drivers/md/dm.c
@@ -533,30 +533,35 @@ static void __clone_and_map(struct clone
} 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);
-
- 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);
+ do {
+ if (offset) {
+ ti = dm_table_find_target(ci->map, ci->sector);
+ max = max_io_len(ci->md, ci->sector, ti);
+
+ 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++;
}
}
--
-
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