NVMe: Initialize iod nents to 0

For commands that do not map a scatter list, we need to initilaize the iod's
number of sg entries (nents) to 0 and not unmap in this case.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 270805cf8d42e642ffb7164cadbbe7cc1d99e732..993c014d195ac403cd1f3547b6de6ae4b41d0584 100644 (file)
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -337,6 +337,7 @@ nvme_alloc_iod(unsigned nseg, unsigned nbytes, gfp_t gfp)
                iod->offset = offsetof(struct nvme_iod, sg[nseg]);
                iod->npages = -1;
                iod->length = nbytes;
+               iod->nents = 0;
        }
 
        return iod;
@@ -377,7 +378,8 @@ static void bio_completion(struct nvme_dev *dev, void *ctx,
        struct bio *bio = iod->private;
        u16 status = le16_to_cpup(&cqe->status) >> 1;
 
-       dma_unmap_sg(&dev->pci_dev->dev, iod->sg, iod->nents,
+       if (iod->nents)
+               dma_unmap_sg(&dev->pci_dev->dev, iod->sg, iod->nents,
                        bio_data_dir(bio) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
        nvme_free_iod(dev, iod);
        if (status) {