virtio: Add transport feature handling stub for virtio_ring.

[linux-2.6-omap-h63xx.git] / block / blk-map.c

diff --git a/block/blk-map.c b/block/blk-map.c
index 813011ef8276e8e2f7c7858a5d70eeb86255574a..ddd96fb11a7d71638a32e3e9060aac1f1adac808 100644 (file)
--- 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