drm: Cleanup after failing to create master->unique and dev->name

v2: Userspace (notably xf86-video-{intel,ati}) became confused when
drmSetInterfaceVersion() started returning -EBUSY as they used a second
call (the first done in drmOpen()) to check their master credentials.
Since userspace wants to be able to repeatedly call
drmSetInterfaceVersion() allow them to do so.

v3: Rebase to drm-core-next.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 66 insertions, 19 deletions

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 76d3d18056dd..7b03b197fc00 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -64,6 +64,19 @@ int drm_getunique(struct drm_device *dev, void *data,
         return 0;
 }
 
+static void
+drm_unset_busid(struct drm_device *dev,
+                struct drm_master *master)
+{
+        kfree(dev->devname);
+        dev->devname = NULL;
+
+        kfree(master->unique);
+        master->unique = NULL;
+        master->unique_len = 0;
+        master->unique_size = 0;
+}
+
 /**
  * Set the bus id.
  *
@@ -94,17 +107,24 @@ int drm_setunique(struct drm_device *dev, void *data,
         master->unique_len = u->unique_len;
         master->unique_size = u->unique_len + 1;
         master->unique = kmalloc(master->unique_size, GFP_KERNEL);
-        if (!master->unique)
-                return -ENOMEM;
-        if (copy_from_user(master->unique, u->unique, master->unique_len))
-                return -EFAULT;
+        if (!master->unique) {
+                ret = -ENOMEM;
+                goto err;
+        }
+
+        if (copy_from_user(master->unique, u->unique, master->unique_len)) {
+                ret = -EFAULT;
+                goto err;
+        }
 
         master->unique[master->unique_len] = '\0';
 
         dev->devname = kmalloc(strlen(dev->driver->pci_driver.name) +
                                strlen(master->unique) + 2, GFP_KERNEL);
-        if (!dev->devname)
-                return -ENOMEM;
+        if (!dev->devname) {
+                ret = -ENOMEM;
+                goto err;
+        }
 
         sprintf(dev->devname, "%s@%s", dev->driver->pci_driver.name,
                 master->unique);
@@ -113,24 +133,36 @@ int drm_setunique(struct drm_device *dev, void *data,
          * busid.
          */
         ret = sscanf(master->unique, "PCI:%d:%d:%d", &bus, &slot, &func);
-        if (ret != 3)
-                return -EINVAL;
+        if (ret != 3) {
+                ret = -EINVAL;
+                goto err;
+        }
+
         domain = bus >> 8;
         bus &= 0xff;
 
         if ((domain != drm_get_pci_domain(dev)) ||
             (bus != dev->pdev->bus->number) ||
             (slot != PCI_SLOT(dev->pdev->devfn)) ||
-            (func != PCI_FUNC(dev->pdev->devfn)))
-                return -EINVAL;
+            (func != PCI_FUNC(dev->pdev->devfn))) {
+                ret = -EINVAL;
+                goto err;
+        }
 
         return 0;
+
+err:
+        drm_unset_busid(dev, master);
+        return ret;
 }
 
 static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
 {
         struct drm_master *master = file_priv->master;
-        int len;
+        int len, ret;
+
+        if (master->unique != NULL)
+                drm_unset_busid(dev, master);
 
         if (drm_core_check_feature(dev, DRIVER_USE_PLATFORM_DEVICE)) {
                 master->unique_len = 10 + strlen(dev->platformdev->name);
@@ -142,15 +174,20 @@ static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
                 len = snprintf(master->unique, master->unique_len,
                         "platform:%s", dev->platformdev->name);
 
-                if (len > master->unique_len)
+                if (len > master->unique_len) {
                         DRM_ERROR("Unique buffer overflowed\n");
+                        ret = -EINVAL;
+                        goto err;
+                }
 
                 dev->devname =
                         kmalloc(strlen(dev->platformdev->name) +
                                 master->unique_len + 2, GFP_KERNEL);
 
-                if (dev->devname == NULL)
-                        return -ENOMEM;
+                if (dev->devname == NULL) {
+                        ret = -ENOMEM;
+                        goto err;
+                }
 
                 sprintf(dev->devname, "%s@%s", dev->platformdev->name,
                         master->unique);
@@ -168,23 +205,31 @@ static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
                         dev->pdev->bus->number,
                         PCI_SLOT(dev->pdev->devfn),
                         PCI_FUNC(dev->pdev->devfn));
-                if (len >= master->unique_len)
+                if (len >= master->unique_len) {
                         DRM_ERROR("buffer overflow");
-                else
+                        ret = -EINVAL;
+                        goto err;
+                } else
                         master->unique_len = len;
 
                 dev->devname =
                         kmalloc(strlen(dev->driver->pci_driver.name) +
                                 master->unique_len + 2, GFP_KERNEL);
 
-                if (dev->devname == NULL)
-                        return -ENOMEM;
+                if (dev->devname == NULL) {
+                        ret = -ENOMEM;
+                        goto err;
+                }
 
                 sprintf(dev->devname, "%s@%s", dev->driver->pci_driver.name,
                         master->unique);
         }
 
         return 0;
+
+err:
+        drm_unset_busid(dev, master);
+        return ret;
 }
 
 /**
@@ -348,7 +393,9 @@ int drm_setversion(struct drm_device *dev, void *data, struct drm_file *file_pri
                         /*
                          * Version 1.1 includes tying of DRM to specific device
                          */
-                        drm_set_busid(dev, file_priv);
+                        retcode = drm_set_busid(dev, file_priv);
+                        if (retcode)
+                                goto done;
                 }
         }