iommu/s390: Get rid of s390_domain_device

The struct s390_domain_device serves the sole purpose as list entry for
the devices list of a struct s390_domain. As it contains no additional
information besides a list_head and a pointer to the struct zpci_dev we
can simplify things and just thread the device list through struct
zpci_dev directly. This removes the need to allocate during domain
attach and gets rid of one level of indirection during mapping
operations.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20221025115657.1666860-3-schnelle@linux.ibm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 108e732..15f8714 100644 (file)
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -117,6 +117,7 @@ struct zpci_bus {
 struct zpci_dev {
        struct zpci_bus *zbus;
        struct list_head entry;         /* list of all zpci_devices, needed for hotplug, etc. */
+       struct list_head iommu_list;
        struct kref kref;
        struct hotplug_slot hotplug_slot;
 

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index c2e5e81..af83ccd 100644 (file)
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -29,11 +29,6 @@ struct s390_domain {
        spinlock_t              list_lock;
 };
 
-struct s390_domain_device {
-       struct list_head        list;
-       struct zpci_dev         *zdev;
-};
-
 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
 {
        return container_of(dom, struct s390_domain, domain);
@@ -87,21 +82,13 @@ static void s390_domain_free(struct iommu_domain *domain)
 static void __s390_iommu_detach_device(struct zpci_dev *zdev)
 {
        struct s390_domain *s390_domain = zdev->s390_domain;
-       struct s390_domain_device *domain_device, *tmp;
        unsigned long flags;
 
        if (!s390_domain)
                return;
 
        spin_lock_irqsave(&s390_domain->list_lock, flags);
-       list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
-                                list) {
-               if (domain_device->zdev == zdev) {
-                       list_del(&domain_device->list);
-                       kfree(domain_device);
-                       break;
-               }
-       }
+       list_del_init(&zdev->iommu_list);
        spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 
        zpci_unregister_ioat(zdev, 0);
@@ -114,17 +101,12 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 {
        struct s390_domain *s390_domain = to_s390_domain(domain);
        struct zpci_dev *zdev = to_zpci_dev(dev);
-       struct s390_domain_device *domain_device;
        unsigned long flags;
        int cc, rc = 0;
 
        if (!zdev)
                return -ENODEV;
 
-       domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
-       if (!domain_device)
-               return -ENOMEM;
-
        if (zdev->s390_domain)
                __s390_iommu_detach_device(zdev);
        else if (zdev->dma_table)
@@ -132,10 +114,8 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 
        cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
                                virt_to_phys(s390_domain->dma_table));
-       if (cc) {
-               rc = -EIO;
-               goto out_free;
-       }
+       if (cc)
+               return -EIO;
        zdev->dma_table = s390_domain->dma_table;
 
        spin_lock_irqsave(&s390_domain->list_lock, flags);
@@ -151,9 +131,8 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
                rc = -EINVAL;
                goto out_unregister;
        }
-       domain_device->zdev = zdev;
        zdev->s390_domain = s390_domain;
-       list_add(&domain_device->list, &s390_domain->devices);
+       list_add(&zdev->iommu_list, &s390_domain->devices);
        spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 
        return 0;
@@ -161,8 +140,6 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 out_unregister:
        zpci_unregister_ioat(zdev, 0);
        zdev->dma_table = NULL;
-out_free:
-       kfree(domain_device);
 
        return rc;
 }
@@ -206,10 +183,10 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
                                   phys_addr_t pa, dma_addr_t dma_addr,
                                   size_t size, int flags)
 {
-       struct s390_domain_device *domain_device;
        phys_addr_t page_addr = pa & PAGE_MASK;
        dma_addr_t start_dma_addr = dma_addr;
        unsigned long irq_flags, nr_pages, i;
+       struct zpci_dev *zdev;
        unsigned long *entry;
        int rc = 0;
 
@@ -234,8 +211,8 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
        }
 
        spin_lock(&s390_domain->list_lock);
-       list_for_each_entry(domain_device, &s390_domain->devices, list) {
-               rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
+       list_for_each_entry(zdev, &s390_domain->devices, iommu_list) {
+               rc = zpci_refresh_trans((u64)zdev->fh << 32,
                                        start_dma_addr, nr_pages * PAGE_SIZE);
                if (rc)
                        break;