s390/pci: remove pdev pointer from arch data

For each PCI function we need to maintain arch specific data in
struct zpci_dev which also contains a pointer to struct pci_dev.

When a function is registered or deregistered (which is triggered by PCI
common code) we need to adjust that pointer which could interfere with
the machine check handler (triggered by FW) using zpci_dev->pdev.

Since multiple instances of the same pdev could exist at a time this can't
be solved with locking.

Fix that by ditching the pdev pointer and use a bus walk to reach
struct pci_dev (only one instance of a pdev can be registered at the bus
at a time).

Signed-off-by: Sebastian Ott <[e-mail]>
Reviewed-by: Gerald Schaefer <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/pci.h

···
 
 /* Private data per function */
 struct zpci_dev {
-	struct pci_dev	*pdev;
 	struct pci_bus	*bus;
 	struct list_head entry;		/* list of all zpci_devices, needed for hotplug, etc. */
 
···
 /* Debug */
 int zpci_debug_init(void);
 void zpci_debug_exit(void);
-void zpci_debug_init_device(struct zpci_dev *);
+void zpci_debug_init_device(struct zpci_dev *, const char *);
 void zpci_debug_exit_device(struct zpci_dev *);
 void zpci_debug_info(struct zpci_dev *, struct seq_file *);
 

arch/s390/pci/pci.c

···
 
 int pcibios_add_device(struct pci_dev *pdev)
 {
-	struct zpci_dev *zdev = to_zpci(pdev);
 	struct resource *res;
 	int i;
 
-	zdev->pdev = pdev;
 	pdev->dev.groups = zpci_attr_groups;
 	zpci_map_resources(pdev);
 
···
 {
 	struct zpci_dev *zdev = to_zpci(pdev);
 
-	zdev->pdev = pdev;
-	zpci_debug_init_device(zdev);
+	zpci_debug_init_device(zdev, dev_name(&pdev->dev));
 	zpci_fmb_enable_device(zdev);
 
 	return pci_enable_resources(pdev, mask);
···
 
 	zpci_fmb_disable_device(zdev);
 	zpci_debug_exit_device(zdev);
-	zdev->pdev = NULL;
 }
 
 #ifdef CONFIG_HIBERNATE_CALLBACKS

arch/s390/pci/pci_debug.c

···
 	.release = single_release,
 };
 
-void zpci_debug_init_device(struct zpci_dev *zdev)
+void zpci_debug_init_device(struct zpci_dev *zdev, const char *name)
 {
-	zdev->debugfs_dev = debugfs_create_dir(dev_name(&zdev->pdev->dev),
-					       debugfs_root);
+	zdev->debugfs_dev = debugfs_create_dir(name, debugfs_root);
 	if (IS_ERR(zdev->debugfs_dev))
 		zdev->debugfs_dev = NULL;
 

arch/s390/pci/pci_dma.c

···
 	dma_free_cpu_table(table);
 }
 
-static unsigned long __dma_alloc_iommu(struct zpci_dev *zdev,
+static unsigned long __dma_alloc_iommu(struct device *dev,
 				       unsigned long start, int size)
 {
+	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long boundary_size;
 
-	boundary_size = ALIGN(dma_get_seg_boundary(&zdev->pdev->dev) + 1,
+	boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
 			      PAGE_SIZE) >> PAGE_SHIFT;
 	return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
 				start, size, 0, boundary_size, 0);
 }
 
-static unsigned long dma_alloc_iommu(struct zpci_dev *zdev, int size)
+static unsigned long dma_alloc_iommu(struct device *dev, int size)
 {
+	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long offset, flags;
 	int wrap = 0;
 
 	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
-	offset = __dma_alloc_iommu(zdev, zdev->next_bit, size);
+	offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
 	if (offset == -1) {
 		/* wrap-around */
-		offset = __dma_alloc_iommu(zdev, 0, size);
+		offset = __dma_alloc_iommu(dev, 0, size);
 		wrap = 1;
 	}
 
···
 	return offset;
 }
 
-static void dma_free_iommu(struct zpci_dev *zdev, unsigned long offset, int size)
+static void dma_free_iommu(struct device *dev, unsigned long offset, int size)
 {
+	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long flags;
 
 	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
···
 
 	/* This rounds up number of pages based on size and offset */
 	nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
-	iommu_page_index = dma_alloc_iommu(zdev, nr_pages);
+	iommu_page_index = dma_alloc_iommu(dev, nr_pages);
 	if (iommu_page_index == -1) {
 		ret = -ENOSPC;
 		goto out_err;
···
 	return dma_addr + (offset & ~PAGE_MASK);
 
 out_free:
-	dma_free_iommu(zdev, iommu_page_index, nr_pages);
+	dma_free_iommu(dev, iommu_page_index, nr_pages);
 out_err:
 	zpci_err("map error:\n");
 	zpci_err_dma(ret, pa);
···
 
 	atomic64_add(npages, &zdev->unmapped_pages);
 	iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
-	dma_free_iommu(zdev, iommu_page_index, npages);
+	dma_free_iommu(dev, iommu_page_index, npages);
 }
 
 static void *s390_dma_alloc(struct device *dev, size_t size,

arch/s390/pci/pci_event.c

···
 static void __zpci_event_error(struct zpci_ccdf_err *ccdf)
 {
 	struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
-	struct pci_dev *pdev = zdev ? zdev->pdev : NULL;
+	struct pci_dev *pdev = NULL;
 
 	zpci_err("error CCDF:\n");
 	zpci_err_hex(ccdf, sizeof(*ccdf));
+
+	if (zdev)
+		pdev = pci_get_slot(zdev->bus, ZPCI_DEVFN);
 
 	pr_err("%s: Event 0x%x reports an error for PCI function 0x%x\n",
 	       pdev ? pci_name(pdev) : "n/a", ccdf->pec, ccdf->fid);
···
 		return;
 
 	pdev->error_state = pci_channel_io_perm_failure;
+	pci_dev_put(pdev);
 }
 
 void zpci_event_error(void *data)
···
 static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 {
 	struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
-	struct pci_dev *pdev = zdev ? zdev->pdev : NULL;
+	struct pci_dev *pdev = NULL;
 	int ret;
+
+	if (zdev)
+		pdev = pci_get_slot(zdev->bus, ZPCI_DEVFN);
 
 	pr_info("%s: Event 0x%x reconfigured PCI function 0x%x\n",
 		pdev ? pci_name(pdev) : "n/a", ccdf->pec, ccdf->fid);
···
 	default:
 		break;
 	}
+	if (pdev)
+		pci_dev_put(pdev);
 }
 
 void zpci_event_availability(void *data)

drivers/pci/hotplug/s390_pci_hpc.c

···
 static int disable_slot(struct hotplug_slot *hotplug_slot)
 {
 	struct slot *slot = hotplug_slot->private;
+	struct pci_dev *pdev;
 	int rc;
 
 	if (!zpci_fn_configured(slot->zdev->state))
 		return -EIO;
 
-	if (slot->zdev->pdev)
-		pci_stop_and_remove_bus_device_locked(slot->zdev->pdev);
+	pdev = pci_get_slot(slot->zdev->bus, ZPCI_DEVFN);
+	if (pdev) {
+		pci_stop_and_remove_bus_device_locked(pdev);
+		pci_dev_put(pdev);
+	}
 
 	rc = zpci_disable_device(slot->zdev);
 	if (rc)