NVMe: Simplify nvme_unmap_user_pages
By using the iod->nents field (the same way other I/O paths do), we can
avoid recalculating the number of sg entries at unmap time, and make
nvme_unmap_user_pages() easier to call.
Also, use the 'write' parameter instead of assuming DMA_FROM_DEVICE.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 71fc903..3cf82c2 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -1046,6 +1046,7 @@
offset = 0;
}
sg_mark_end(&sg[i - 1]);
+ iod->nents = count;
err = -ENOMEM;
nents = dma_map_sg(&dev->pci_dev->dev, sg, count,
@@ -1066,16 +1067,15 @@
}
static void nvme_unmap_user_pages(struct nvme_dev *dev, int write,
- unsigned long addr, int length, struct nvme_iod *iod)
+ struct nvme_iod *iod)
{
- struct scatterlist *sg = iod->sg;
- int i, count;
+ int i;
- count = DIV_ROUND_UP(offset_in_page(addr) + length, PAGE_SIZE);
- dma_unmap_sg(&dev->pci_dev->dev, sg, count, DMA_FROM_DEVICE);
+ dma_unmap_sg(&dev->pci_dev->dev, iod->sg, iod->nents,
+ write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
- for (i = 0; i < count; i++)
- put_page(sg_page(&sg[i]));
+ for (i = 0; i < iod->nents; i++)
+ put_page(sg_page(&iod->sg[i]));
}
static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
@@ -1132,7 +1132,7 @@
else
status = nvme_submit_sync_cmd(nvmeq, &c, NULL, NVME_IO_TIMEOUT);
- nvme_unmap_user_pages(dev, io.opcode & 1, io.addr, length, iod);
+ nvme_unmap_user_pages(dev, io.opcode & 1, iod);
nvme_free_iod(dev, iod);
return status;
}
@@ -1180,8 +1180,7 @@
status = nvme_submit_admin_cmd(dev, &c, NULL);
if (cmd.data_len) {
- nvme_unmap_user_pages(dev, cmd.opcode & 1, cmd.addr,
- cmd.data_len, iod);
+ nvme_unmap_user_pages(dev, cmd.opcode & 1, iod);
nvme_free_iod(dev, iod);
}
return status;