From 36c14ed9caa957c686d4a48fd598a5ec2aa0331b Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 24 Jan 2011 07:52:07 -0500 Subject: [PATCH] NVMe: Use PRP2 for the nvme_identify ioctl DMA the result straight to userspace instead of bounce-buffering in the kernel. Signed-off-by: Matthew Wilcox --- drivers/block/nvme.c | 58 +++++++++++++++++++++++++++++++------------- 1 file changed, 41 insertions(+), 17 deletions(-) diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c index 44a9d5edd8db..c0ef1dd1cc90 100644 --- a/drivers/block/nvme.c +++ b/drivers/block/nvme.c @@ -647,33 +647,57 @@ static int __devinit nvme_configure_admin_queue(struct nvme_dev *dev) return result; } -static int nvme_identify(struct nvme_ns *ns, void __user *addr, int cns) +static int nvme_identify(struct nvme_ns *ns, unsigned long addr, int cns) { struct nvme_dev *dev = ns->dev; - int status; + int i, err, count, nents, offset; struct nvme_command c; - void *page; - dma_addr_t dma_addr; - - page = dma_alloc_coherent(&dev->pci_dev->dev, 4096, &dma_addr, - GFP_KERNEL); + struct scatterlist sg[2]; + struct page *pages[2]; + + if (addr & 3) + return -EINVAL; + offset = offset_in_page(addr); + count = offset ? 2 : 1; + + err = get_user_pages_fast(addr, count, 1, pages); + if (err < count) { + count = err; + err = -EFAULT; + goto put_pages; + } + sg_init_table(sg, count); + for (i = 0; i < count; i++) + sg_set_page(&sg[i], pages[i], PAGE_SIZE, 0); + nents = dma_map_sg(&dev->pci_dev->dev, sg, count, DMA_FROM_DEVICE); + if (!nents) + goto put_pages; memset(&c, 0, sizeof(c)); c.identify.opcode = nvme_admin_identify; c.identify.nsid = cns ? 0 : cpu_to_le32(ns->ns_id); - c.identify.prp1 = cpu_to_le64(dma_addr); + c.identify.prp1 = cpu_to_le64(sg_dma_address(&sg[0]) + offset); + if (count > 1) { + u64 dma_addr; + if (nents > 1) + dma_addr = sg_dma_address(&sg[1]); + else + dma_addr = sg_dma_address(&sg[0]) + PAGE_SIZE; + c.identify.prp2 = cpu_to_le64(dma_addr); + } c.identify.cns = cpu_to_le32(cns); - status = nvme_submit_admin_cmd(dev, &c, NULL); + err = nvme_submit_admin_cmd(dev, &c, NULL); - if (status) - status = -EIO; - else if (copy_to_user(addr, page, 4096)) - status = -EFAULT; + if (err) + err = -EIO; - dma_free_coherent(&dev->pci_dev->dev, 4096, page, dma_addr); + dma_unmap_sg(&dev->pci_dev->dev, sg, nents, DMA_FROM_DEVICE); + put_pages: + for (i = 0; i < count; i++) + put_page(pages[i]); - return status; + return err; } static int nvme_get_range_type(struct nvme_ns *ns, void __user *addr) @@ -713,9 +737,9 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, switch (cmd) { case NVME_IOCTL_IDENTIFY_NS: - return nvme_identify(ns, (void __user *)arg, 0); + return nvme_identify(ns, arg, 0); case NVME_IOCTL_IDENTIFY_CTRL: - return nvme_identify(ns, (void __user *)arg, 1); + return nvme_identify(ns, arg, 1); case NVME_IOCTL_GET_RANGE_TYPE: return nvme_get_range_type(ns, (void __user *)arg); default: -- 2.34.1