diff options
| author | Jens Axboe <jens.axboe@oracle.com> | 2007-10-23 09:49:25 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2007-10-23 09:49:25 +0200 |
| commit | 7aeacf982203fb4dea2f3434eefdc268cfd5d6d9 (patch) | |
| tree | 93a3991d5ab854fce477d9e28e55b720fd6ac81a | |
| parent | ad0d4083e65d9f223275adbfb9a7927e2120dc6c (diff) | |
[BLOCK] blk_rq_map_sg: force clear termination bit
Since blk_rq_map_sg() sets the termination bit at the end of the sg
table, we could see it prematurely on the next mapping unless we
force drivers to do a full sg_init_table() prior to each mapping. So
force clear the termination bit to avoid having to put that clear in
the driver for every mapping.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| -rw-r--r-- | block/ll_rw_blk.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index fb8fb8852c3..de5ba479c22 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -1351,8 +1351,20 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, new_segment: if (!sg) sg = sglist; - else + else { + /* + * If the driver previously mapped a shorter + * list, we could see a termination bit + * prematurely unless it fully inits the sg + * table on each mapping. We KNOW that there + * must be more entries here or the driver + * would be buggy, so force clear the + * termination bit to avoid doing a full + * sg_init_table() in drivers for each command. + */ + sg->page_link &= ~0x02; sg = sg_next(sg); + } sg_set_page(sg, bvec->bv_page); sg->length = nbytes; |