s390/pci: consolidate SR-IOV specific code

currently we have multiple #ifdef CONFIG_PCI_IOV blocks spread over
different compliation units and headers, all dealing with SR-IOV
specific behavior.
This violates the style guide which discourages conditionally compiled
code blocks and hinders maintainability by speading SR-IOV functionality
over many files.

Let's move all of this into a conditionally compiled pci_iov.c file and
local header and prefix SR-IOV specific functions with zpci_iov_*.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/pci/Makefile

@@ -6,3 +6,4 @@
 obj-$(CONFIG_PCI)	+= pci.o pci_irq.o pci_dma.o pci_clp.o pci_sysfs.o \
 			   pci_event.o pci_debug.o pci_insn.o pci_mmio.o \
 			   pci_bus.o
+obj-$(CONFIG_PCI_IOV)	+= pci_iov.o

arch/s390/pci/pci.c

@@ -37,6 +37,7 @@
 #include <asm/pci_dma.h>
 
 #include "pci_bus.h"
+#include "pci_iov.h"
 
 /* list of all detected zpci devices */
 static LIST_HEAD(zpci_list);
@@ -413,15 +414,6 @@ static struct pci_ops pci_root_ops = {
 	.write = pci_write,
 };
 
-#ifdef CONFIG_PCI_IOV
-static struct resource iov_res = {
-	.name	= "PCI IOV res",
-	.start	= 0,
-	.end	= -1,
-	.flags	= IORESOURCE_MEM,
-};
-#endif
-
 static void zpci_map_resources(struct pci_dev *pdev)
 {
 	struct zpci_dev *zdev = to_zpci(pdev);
@@ -442,16 +434,7 @@ static void zpci_map_resources(struct pci_dev *pdev)
 		pdev->resource[i].end = pdev->resource[i].start + len - 1;
 	}
 
-#ifdef CONFIG_PCI_IOV
+	zpci_iov_map_resources(pdev);
-	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
-		int bar = i + PCI_IOV_RESOURCES;
-
-		len = pci_resource_len(pdev, bar);
-		if (!len)
-			continue;
-		pdev->resource[bar].parent = &iov_res;
-	}
-#endif
 }
 
 static void zpci_unmap_resources(struct pci_dev *pdev)
@@ -703,7 +686,7 @@ void zpci_remove_device(struct zpci_dev *zdev)
 	pdev = pci_get_slot(zbus->bus, zdev->devfn);
 	if (pdev) {
 		if (pdev->is_virtfn)
-			return zpci_remove_virtfn(pdev, zdev->vfn);
+			return zpci_iov_remove_virtfn(pdev, zdev->vfn);
 		pci_stop_and_remove_bus_device_locked(pdev);
 	}
 }

arch/s390/pci/pci_bus.c

@@ -24,6 +24,7 @@
 #include <asm/pci_dma.h>
 
 #include "pci_bus.h"
+#include "pci_iov.h"
 
 static LIST_HEAD(zbus_list);
 static DEFINE_SPINLOCK(zbus_list_lock);
@@ -126,69 +127,6 @@ static struct zpci_bus *zpci_bus_alloc(int pchid)
 	return zbus;
 }
 
-#ifdef CONFIG_PCI_IOV
-static int zpci_bus_link_virtfn(struct pci_dev *pdev,
-		struct pci_dev *virtfn, int vfid)
-{
-	int rc;
-
-	rc = pci_iov_sysfs_link(pdev, virtfn, vfid);
-	if (rc)
-		return rc;
-
-	virtfn->is_virtfn = 1;
-	virtfn->multifunction = 0;
-	virtfn->physfn = pci_dev_get(pdev);
-
-	return 0;
-}
-
-static int zpci_bus_setup_virtfn(struct zpci_bus *zbus,
-		struct pci_dev *virtfn, int vfn)
-{
-	int i, cand_devfn;
-	struct zpci_dev *zdev;
-	struct pci_dev *pdev;
-	int vfid = vfn - 1; /* Linux' vfid's start at 0 vfn at 1*/
-	int rc = 0;
-
-	if (!zbus->multifunction)
-		return 0;
-
-	/* If the parent PF for the given VF is also configured in the
-	 * instance, it must be on the same zbus.
-	 * We can then identify the parent PF by checking what
-	 * devfn the VF would have if it belonged to that PF using the PF's
-	 * stride and offset. Only if this candidate devfn matches the
-	 * actual devfn will we link both functions.
-	 */
-	for (i = 0; i < ZPCI_FUNCTIONS_PER_BUS; i++) {
-		zdev = zbus->function[i];
-		if (zdev && zdev->is_physfn) {
-			pdev = pci_get_slot(zbus->bus, zdev->devfn);
-			if (!pdev)
-				continue;
-			cand_devfn = pci_iov_virtfn_devfn(pdev, vfid);
-			if (cand_devfn == virtfn->devfn) {
-				rc = zpci_bus_link_virtfn(pdev, virtfn, vfid);
-				/* balance pci_get_slot() */
-				pci_dev_put(pdev);
-				break;
-			}
-			/* balance pci_get_slot() */
-			pci_dev_put(pdev);
-		}
-	}
-	return rc;
-}
-#else
-static inline int zpci_bus_setup_virtfn(struct zpci_bus *zbus,
-		struct pci_dev *virtfn, int vfn)
-{
-	return 0;
-}
-#endif
-
 void pcibios_bus_add_device(struct pci_dev *pdev)
 {
 	struct zpci_dev *zdev = to_zpci(pdev);
@@ -198,7 +136,7 @@ void pcibios_bus_add_device(struct pci_dev *pdev)
 	 * perform PF/VF linking.
 	 */
 	if (zdev->vfn)
-		zpci_bus_setup_virtfn(zdev->zbus, pdev, zdev->vfn);
+		zpci_iov_setup_virtfn(zdev->zbus, pdev, zdev->vfn);
 
 }
 

arch/s390/pci/pci_bus.h

@@ -30,15 +30,3 @@ static inline struct zpci_dev *get_zdev_by_bus(struct pci_bus *bus,
 	return (devfn >= ZPCI_FUNCTIONS_PER_BUS) ? NULL : zbus->function[devfn];
 }
 
-#ifdef CONFIG_PCI_IOV
-static inline void zpci_remove_virtfn(struct pci_dev *pdev, int vfn)
-{
-
-	pci_lock_rescan_remove();
-	/* Linux' vfid's start at 0 vfn at 1 */
-	pci_iov_remove_virtfn(pdev->physfn, vfn - 1);
-	pci_unlock_rescan_remove();
-}
-#else /* CONFIG_PCI_IOV */
-static inline void zpci_remove_virtfn(struct pci_dev *pdev, int vfn) {}
-#endif /* CONFIG_PCI_IOV */

arch/s390/pci/pci_iov.c

@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2020
+ *
+ * Author(s):
+ *   Niklas Schnelle <schnelle@linux.ibm.com>
+ *
+ */
+
+#define KMSG_COMPONENT "zpci"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+
+static struct resource iov_res = {
+	.name	= "PCI IOV res",
+	.start	= 0,
+	.end	= -1,
+	.flags	= IORESOURCE_MEM,
+};
+
+void zpci_iov_map_resources(struct pci_dev *pdev)
+{
+	resource_size_t len;
+	int i;
+
+	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
+		int bar = i + PCI_IOV_RESOURCES;
+
+		len = pci_resource_len(pdev, bar);
+		if (!len)
+			continue;
+		pdev->resource[bar].parent = &iov_res;
+	}
+}
+
+void zpci_iov_remove_virtfn(struct pci_dev *pdev, int vfn)
+{
+	pci_lock_rescan_remove();
+	/* Linux' vfid's start at 0 vfn at 1 */
+	pci_iov_remove_virtfn(pdev->physfn, vfn - 1);
+	pci_unlock_rescan_remove();
+}
+
+static int zpci_iov_link_virtfn(struct pci_dev *pdev, struct pci_dev *virtfn, int vfid)
+{
+	int rc;
+
+	rc = pci_iov_sysfs_link(pdev, virtfn, vfid);
+	if (rc)
+		return rc;
+
+	virtfn->is_virtfn = 1;
+	virtfn->multifunction = 0;
+	virtfn->physfn = pci_dev_get(pdev);
+
+	return 0;
+}
+
+int zpci_iov_setup_virtfn(struct zpci_bus *zbus, struct pci_dev *virtfn, int vfn)
+{
+	int i, cand_devfn;
+	struct zpci_dev *zdev;
+	struct pci_dev *pdev;
+	int vfid = vfn - 1; /* Linux' vfid's start at 0 vfn at 1*/
+	int rc = 0;
+
+	if (!zbus->multifunction)
+		return 0;
+
+	/* If the parent PF for the given VF is also configured in the
+	 * instance, it must be on the same zbus.
+	 * We can then identify the parent PF by checking what
+	 * devfn the VF would have if it belonged to that PF using the PF's
+	 * stride and offset. Only if this candidate devfn matches the
+	 * actual devfn will we link both functions.
+	 */
+	for (i = 0; i < ZPCI_FUNCTIONS_PER_BUS; i++) {
+		zdev = zbus->function[i];
+		if (zdev && zdev->is_physfn) {
+			pdev = pci_get_slot(zbus->bus, zdev->devfn);
+			if (!pdev)
+				continue;
+			cand_devfn = pci_iov_virtfn_devfn(pdev, vfid);
+			if (cand_devfn == virtfn->devfn) {
+				rc = zpci_iov_link_virtfn(pdev, virtfn, vfid);
+				/* balance pci_get_slot() */
+				pci_dev_put(pdev);
+				break;
+			}
+			/* balance pci_get_slot() */
+			pci_dev_put(pdev);
+		}
+	}
+	return rc;
+}

arch/s390/pci/pci_iov.h

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright IBM Corp. 2020
+ *
+ * Author(s):
+ *   Niklas Schnelle <schnelle@linux.ibm.com>
+ *
+ */
+
+#ifndef __S390_PCI_IOV_H
+#define __S390_PCI_IOV_H
+
+#ifdef CONFIG_PCI_IOV
+void zpci_iov_remove_virtfn(struct pci_dev *pdev, int vfn);
+
+void zpci_iov_map_resources(struct pci_dev *pdev);
+
+int zpci_iov_setup_virtfn(struct zpci_bus *zbus, struct pci_dev *virtfn, int vfn);
+
+#else /* CONFIG_PCI_IOV */
+static inline void zpci_iov_remove_virtfn(struct pci_dev *pdev, int vfn) {}
+
+static inline void zpci_iov_map_resources(struct pci_dev *pdev) {}
+
+static inline int zpci_iov_setup_virtfn(struct zpci_bus *zbus, struct pci_dev *virtfn, int vfn)
+{
+	return 0;
+}
+#endif /* CONFIG_PCI_IOV */
+#endif /* __S390_PCI_IOV_h */