NVMe: Create nvme_map_user_pages() and nvme_unmap_user_pages() (7fc3cdab) · Commits · 戴 / test

drivers/block/nvme.c

+53 −15

Original line number	Diff line number	Diff line
		@@ -677,17 +677,22 @@ static int __devinit nvme_configure_admin_queue(struct nvme_dev *dev)
		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) {
		@@ -695,27 +700,60 @@ static int nvme_submit_user_admin_command(struct nvme_dev *dev, unsigned long ad
		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);
		put_pages:
		for (i = 0; i < count; i++)
		put_page(pages[i]);
		kfree(pages);
		return err;
		}

		if (err)
		err = -EIO;
		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);
		put_pages:

		for (i = 0; i < count; i++)
		put_page(pages[i]);
		put_page(sg_page(&sg[i]));
		}

		return err;
		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)

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