vfio-pci: Cleanup read/write functions

The read and write functions are nearly identical, combine them
and convert to a switch statement.  This also makes it easy to
narrow the scope of when we use the io/mem accessors in case new
regions are added.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 29 insertions, 30 deletions

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index b28e66c4376a..469e110d7ea6 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -366,8 +366,8 @@ static long vfio_pci_ioctl(void *device_data,
         return -ENOTTY;
 }
 
-static ssize_t vfio_pci_read(void *device_data, char __user *buf,
-                             size_t count, loff_t *ppos)
+static ssize_t vfio_pci_rw(void *device_data, char __user *buf,
+                           size_t count, loff_t *ppos, bool iswrite)
 {
         unsigned int index = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
         struct vfio_pci_device *vdev = device_data;
@@ -376,42 +376,41 @@ static ssize_t vfio_pci_read(void *device_data, char __user *buf,
         if (index >= VFIO_PCI_NUM_REGIONS)
                 return -EINVAL;
 
-        if (index == VFIO_PCI_CONFIG_REGION_INDEX)
-                return vfio_pci_config_readwrite(vdev, buf, count, ppos, false);
-        else if (index == VFIO_PCI_ROM_REGION_INDEX)
-                return vfio_pci_mem_readwrite(vdev, buf, count, ppos, false);
-        else if (pci_resource_flags(pdev, index) & IORESOURCE_IO)
-                return vfio_pci_io_readwrite(vdev, buf, count, ppos, false);
-        else if (pci_resource_flags(pdev, index) & IORESOURCE_MEM)
+        switch (index) {
+        case VFIO_PCI_CONFIG_REGION_INDEX:
+                return vfio_pci_config_readwrite(vdev, buf, count,
+                                                 ppos, iswrite);
+        case VFIO_PCI_ROM_REGION_INDEX:
+                if (iswrite)
+                        return -EINVAL;
                 return vfio_pci_mem_readwrite(vdev, buf, count, ppos, false);
 
+        case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
+        {
+                unsigned long flags = pci_resource_flags(pdev, index);
+
+                if (flags & IORESOURCE_IO)
+                        return vfio_pci_io_readwrite(vdev, buf, count,
+                                                     ppos, iswrite);
+                if (flags & IORESOURCE_MEM)
+                        return vfio_pci_mem_readwrite(vdev, buf, count,
+                                                      ppos, iswrite);
+        }
+        }
+
         return -EINVAL;
 }
 
+static ssize_t vfio_pci_read(void *device_data, char __user *buf,
+                             size_t count, loff_t *ppos)
+{
+        return vfio_pci_rw(device_data, buf, count, ppos, false);
+}
+
 static ssize_t vfio_pci_write(void *device_data, const char __user *buf,
                               size_t count, loff_t *ppos)
 {
-        unsigned int index = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
-        struct vfio_pci_device *vdev = device_data;
-        struct pci_dev *pdev = vdev->pdev;
-
-        if (index >= VFIO_PCI_NUM_REGIONS)
-                return -EINVAL;
-
-        if (index == VFIO_PCI_CONFIG_REGION_INDEX)
-                return vfio_pci_config_readwrite(vdev, (char __user *)buf,
-                                                 count, ppos, true);
-        else if (index == VFIO_PCI_ROM_REGION_INDEX)
-                return -EINVAL;
-        else if (pci_resource_flags(pdev, index) & IORESOURCE_IO)
-                return vfio_pci_io_readwrite(vdev, (char __user *)buf,
-                                             count, ppos, true);
-        else if (pci_resource_flags(pdev, index) & IORESOURCE_MEM) {
-                return vfio_pci_mem_readwrite(vdev, (char __user *)buf,
-                                              count, ppos, true);
-        }
-
-        return -EINVAL;
+        return vfio_pci_rw(device_data, buf, count, ppos, true);
 }
 
 static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)