powerpc/eeh: Rework pci_dev lookup in debugfs attributes

Pull the string -> pci_dev lookup stuff into a helper function. No functional change.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201103051512.919333-1-oohall@gmail.com

arch/powerpc/kernel/eeh.c

@@ -1596,6 +1596,35 @@ static int proc_eeh_show(struct seq_file *m, void *v)
 }
 
 #ifdef CONFIG_DEBUG_FS
+
+
+static struct pci_dev *eeh_debug_lookup_pdev(struct file *filp,
+					     const char __user *user_buf,
+					     size_t count, loff_t *ppos)
+{
+	uint32_t domain, bus, dev, fn;
+	struct pci_dev *pdev;
+	char buf[20];
+	int ret;
+
+	memset(buf, 0, sizeof(buf));
+	ret = simple_write_to_buffer(buf, sizeof(buf)-1, ppos, user_buf, count);
+	if (!ret)
+		return ERR_PTR(-EFAULT);
+
+	ret = sscanf(buf, "%x:%x:%x.%x", &domain, &bus, &dev, &fn);
+	if (ret != 4) {
+		pr_err("%s: expected 4 args, got %d\n", __func__, ret);
+		return ERR_PTR(-EINVAL);
+	}
+
+	pdev = pci_get_domain_bus_and_slot(domain, bus, (dev << 3) | fn);
+	if (!pdev)
+		return ERR_PTR(-ENODEV);
+
+	return pdev;
+}
+
 static int eeh_enable_dbgfs_set(void *data, u64 val)
 {
 	if (val)
@@ -1688,26 +1717,13 @@ static ssize_t eeh_dev_check_write(struct file *filp,
 				const char __user *user_buf,
 				size_t count, loff_t *ppos)
 {
-	uint32_t domain, bus, dev, fn;
 	struct pci_dev *pdev;
 	struct eeh_dev *edev;
-	char buf[20];
 	int ret;
 
-	memset(buf, 0, sizeof(buf));
-	ret = simple_write_to_buffer(buf, sizeof(buf)-1, ppos, user_buf, count);
-	if (!ret)
-		return -EFAULT;
-
-	ret = sscanf(buf, "%x:%x:%x.%x", &domain, &bus, &dev, &fn);
-	if (ret != 4) {
-		pr_err("%s: expected 4 args, got %d\n", __func__, ret);
-		return -EINVAL;
-	}
-
-	pdev = pci_get_domain_bus_and_slot(domain, bus, (dev << 3) | fn);
-	if (!pdev)
-		return -ENODEV;
+	pdev = eeh_debug_lookup_pdev(filp, user_buf, count, ppos);
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
 
 	edev = pci_dev_to_eeh_dev(pdev);
 	if (!edev) {
@@ -1717,8 +1733,8 @@ static ssize_t eeh_dev_check_write(struct file *filp,
 	}
 
 	ret = eeh_dev_check_failure(edev);
-	pci_info(pdev, "eeh_dev_check_failure(%04x:%02x:%02x.%01x) = %d\n",
-			domain, bus, dev, fn, ret);
+	pci_info(pdev, "eeh_dev_check_failure(%s) = %d\n",
+			pci_name(pdev), ret);
 
 	pci_dev_put(pdev);
 
@@ -1829,25 +1845,12 @@ static ssize_t eeh_dev_break_write(struct file *filp,
 				const char __user *user_buf,
 				size_t count, loff_t *ppos)
 {
-	uint32_t domain, bus, dev, fn;
 	struct pci_dev *pdev;
-	char buf[20];
 	int ret;
 
-	memset(buf, 0, sizeof(buf));
-	ret = simple_write_to_buffer(buf, sizeof(buf)-1, ppos, user_buf, count);
-	if (!ret)
-		return -EFAULT;
-
-	ret = sscanf(buf, "%x:%x:%x.%x", &domain, &bus, &dev, &fn);
-	if (ret != 4) {
-		pr_err("%s: expected 4 args, got %d\n", __func__, ret);
-		return -EINVAL;
-	}
-
-	pdev = pci_get_domain_bus_and_slot(domain, bus, (dev << 3) | fn);
-	if (!pdev)
-		return -ENODEV;
+	pdev = eeh_debug_lookup_pdev(filp, user_buf, count, ppos);
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
 
 	ret = eeh_debugfs_break_device(pdev);
 	pci_dev_put(pdev);