NVMe: Create nvme_map_user_pages() and nvme_unmap_user_pages()
These are generalisations of the code that was in
nvme_submit_user_admin_command().
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index b28d188..f44d6cd 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -677,17 +677,22 @@
return result;
}
-static int nvme_submit_user_admin_command(struct nvme_dev *dev, unsigned long addr,
- unsigned length, struct nvme_command *cmd)
+static int nvme_map_user_pages(struct nvme_dev *dev, int write,
+ unsigned long addr, unsigned length,
+ struct scatterlist **sgp)
{
int i, err, count, nents, offset;
- struct scatterlist sg[2];
- struct page *pages[2];
+ struct scatterlist *sg;
+ struct page **pages;
if (addr & 3)
return -EINVAL;
+ if (!length)
+ return -EINVAL;
+
offset = offset_in_page(addr);
- count = ((offset + length) > PAGE_SIZE) ? 2 : 1;
+ count = DIV_ROUND_UP(offset + length, PAGE_SIZE);
+ pages = kcalloc(count, sizeof(*pages), GFP_KERNEL);
err = get_user_pages_fast(addr, count, 1, pages);
if (err < count) {
@@ -695,29 +700,62 @@
err = -EFAULT;
goto put_pages;
}
+
+ sg = kcalloc(count, sizeof(*sg), GFP_KERNEL);
sg_init_table(sg, count);
sg_set_page(&sg[0], pages[0], PAGE_SIZE - offset, offset);
- if (count > 1)
- sg_set_page(&sg[1], pages[1], offset, 0);
- nents = dma_map_sg(&dev->pci_dev->dev, sg, count, DMA_FROM_DEVICE);
+ length -= (PAGE_SIZE - offset);
+ for (i = 1; i < count; i++) {
+ sg_set_page(&sg[i], pages[i], min_t(int, length, PAGE_SIZE), 0);
+ length -= PAGE_SIZE;
+ }
+
+ err = -ENOMEM;
+ nents = dma_map_sg(&dev->pci_dev->dev, sg, count,
+ write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
if (!nents)
goto put_pages;
- nvme_setup_prps(&cmd->common, sg, length);
+ kfree(pages);
+ *sgp = sg;
+ return nents;
- err = nvme_submit_admin_cmd(dev, cmd, NULL);
-
- if (err)
- err = -EIO;
-
- dma_unmap_sg(&dev->pci_dev->dev, sg, nents, DMA_FROM_DEVICE);
put_pages:
for (i = 0; i < count; i++)
put_page(pages[i]);
-
+ kfree(pages);
return err;
}
+static void nvme_unmap_user_pages(struct nvme_dev *dev, int write,
+ unsigned long addr, int length,
+ struct scatterlist *sg, int nents)
+{
+ int i, count;
+
+ count = DIV_ROUND_UP(offset_in_page(addr) + length, PAGE_SIZE);
+ dma_unmap_sg(&dev->pci_dev->dev, sg, nents, DMA_FROM_DEVICE);
+
+ for (i = 0; i < count; i++)
+ put_page(sg_page(&sg[i]));
+}
+
+static int nvme_submit_user_admin_command(struct nvme_dev *dev,
+ unsigned long addr, unsigned length,
+ struct nvme_command *cmd)
+{
+ int err, nents;
+ struct scatterlist *sg;
+
+ nents = nvme_map_user_pages(dev, 0, addr, length, &sg);
+ if (nents < 0)
+ return nents;
+ nvme_setup_prps(&cmd->common, sg, length);
+ err = nvme_submit_admin_cmd(dev, cmd, NULL);
+ nvme_unmap_user_pages(dev, 0, addr, length, sg, nents);
+ return err ? -EIO : 0;
+}
+
static int nvme_identify(struct nvme_ns *ns, unsigned long addr, int cns)
{
struct nvme_command c;