diff options
| -rw-r--r-- | block/blk-map.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/block/blk-map.c b/block/blk-map.c index 813011ef827..ddd96fb11a7 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -269,6 +269,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, int reading = rq_data_dir(rq) == READ; int do_copy = 0; struct bio *bio; + unsigned long stack_mask = ~(THREAD_SIZE - 1); if (len > (q->max_hw_sectors << 9)) return -EINVAL; @@ -279,6 +280,10 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, alignment = queue_dma_alignment(q) | q->dma_pad_mask; do_copy = ((kaddr & alignment) || (len & alignment)); + if (!((kaddr & stack_mask) ^ + ((unsigned long)current->stack & stack_mask))) + do_copy = 1; + if (do_copy) bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); else |