nvme: fix uninitialized prp2 value on small transfers

The value of iod->first_dma ends up as prp2 in NVMe commands. In case
there is not enough data to cross a page boundary, iod->first_dma is
never initialized and contains random data.

Comply with the NVMe specification and fill in 0 in that case.

Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index e628374..544805a 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -555,8 +555,10 @@ static blk_status_t nvme_setup_prps(struct nvme_dev *dev, struct request *req)
        int nprps, i;
 
        length -= (page_size - offset);
-       if (length <= 0)
+       if (length <= 0) {
+               iod->first_dma = 0;
                return BLK_STS_OK;
+       }
 
        dma_len -= (page_size - offset);
        if (dma_len) {