Re: [PATCH v3 11/11] nvmet: Optionally use PCI P2P memory

+				  const char *page, size_t count)
+{
+	struct nvmet_port *port = to_nvmet_port(item);
+	struct device *dev;
+	struct pci_dev *p2p_dev = NULL;
+	bool use_p2pmem;
+
+	switch (page[0]) {
+	case 'y':
+	case 'Y':
+	case 'a':
+	case 'A':
+		use_p2pmem = true;
+		break;
+	case 'n':
+	case 'N':
+		use_p2pmem = false;
+		break;
+	default:
+		dev = bus_find_device_by_name(&pci_bus_type, NULL, page);
+		if (!dev) {
+			pr_err("No such PCI device: %s\n", page);
+			return -ENODEV;
+		}
+
+		use_p2pmem = true;
+		p2p_dev = to_pci_dev(dev);
+
+		if (!pci_has_p2pmem(p2p_dev)) {
+			pr_err("PCI device has no peer-to-peer memory: %s\n",
+			       page);
+			pci_dev_put(p2p_dev);
+			return -ENODEV;
+		}
+	}

Yikes.  Shouldn't auto just be the normal yes case instead of this
string parsing mess?

+	if (rsp->req.sg != &rsp->cmd->inline_sg) {
+		if (rsp->req.p2p_dev)
+			pci_p2pmem_free_sgl(rsp->req.p2p_dev, rsp->req.sg,
+					    rsp->req.sg_cnt);
+		else
+			sgl_free(rsp->req.sg);
+	}

Can we factor this into a helper, as the other target drivers (fc for now,
tcp soon) using sgl allocatins should share the code?

(same for the alloc side)