Merge branch 'bkl-removal' into next

[pandora-kernel.git] / block / blk-map.c

diff --git a/block/blk-map.c b/block/blk-map.c
index 3c942bd..ddd96fb 100644 (file)
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -210,6 +210,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
        if (!bio_flagged(bio, BIO_USER_MAPPED))
                rq->cmd_flags |= REQ_COPY_USER;
 
+       blk_queue_bounce(q, &bio);
        bio_get(bio);
        blk_rq_bio_prep(q, rq, bio);
        rq->buffer = rq->data = NULL;
@@ -255,24 +256,48 @@ EXPORT_SYMBOL(blk_rq_unmap_user);
  * @kbuf:      the kernel buffer
  * @len:       length of user data
  * @gfp_mask:  memory allocation flags
+ *
+ * Description:
+ *    Data will be mapped directly if possible. Otherwise a bounce
+ *    buffer is used.
  */
 int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
                    unsigned int len, gfp_t gfp_mask)
 {
+       unsigned long kaddr;
+       unsigned int alignment;
+       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;
        if (!len || !kbuf)
                return -EINVAL;
 
-       bio = bio_map_kern(q, kbuf, len, gfp_mask);
+       kaddr = (unsigned long)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
+               bio = bio_map_kern(q, kbuf, len, gfp_mask);
+
        if (IS_ERR(bio))
                return PTR_ERR(bio);
 
        if (rq_data_dir(rq) == WRITE)
                bio->bi_rw |= (1 << BIO_RW);
 
+       if (do_copy)
+               rq->cmd_flags |= REQ_COPY_USER;
+
        blk_rq_bio_prep(q, rq, bio);
        blk_queue_bounce(q, &rq->bio);
        rq->buffer = rq->data = NULL;