virtio_blk: don't bounce highmem requests

commit 4eff3cae9c9809720c636e64bc72f212258e0bd5 upstream

virtio_blk: don't bounce highmem requests

By default a block driver bounces highmem requests, but virtio-blk is
perfectly fine with any request that fit into it's 64 bit addressing scheme,
mapped in the kernel virtual space or not.

Besides improving performance on highmem systems this also makes the
reproducible oops in __bounce_end_io go away (but hiding the real cause).

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 5d34764c8a8726d5103e6e723eaae6ab28a6a422..69c6dbdd2511a06a939d2a00fb9228cb9900b290 100644 (file)
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -308,6 +308,9 @@ static int virtblk_probe(struct virtio_device *vdev)
        else
                blk_queue_max_segment_size(vblk->disk->queue, -1U);
 
+       /* No need to bounce any requests */
+       blk_queue_bounce_limit(vblk->disk->queue, BLK_BOUNCE_ANY);
+
        /* Host can optionally specify the block size of the device */
        err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
                                offsetof(struct virtio_blk_config, blk_size),