udl-kms: handle allocation failure

commit 542bb9788a1f485eb1a2229178f665d8ea166156 upstream.

Allocations larger than PAGE_ALLOC_COSTLY_ORDER are unreliable and they
may fail anytime. This patch fixes the udl kms driver so that when a large
alloactions fails, it tries to do multiple smaller allocations.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 2d7d7e0..30bfeb1 100644 (file)
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -171,17 +171,22 @@ static void udl_free_urb_list(struct drm_device *dev)
 static int udl_alloc_urb_list(struct drm_device *dev, int count, size_t size)
 {
        struct udl_device *udl = dev->dev_private;
-       int i = 0;
        struct urb *urb;
        struct urb_node *unode;
        char *buf;
+       size_t wanted_size = count * size;
 
        spin_lock_init(&udl->urbs.lock);
 
+retry:
        udl->urbs.size = size;
        INIT_LIST_HEAD(&udl->urbs.list);
 
-       while (i < count) {
+       sema_init(&udl->urbs.limit_sem, 0);
+       udl->urbs.count = 0;
+       udl->urbs.available = 0;
+
+       while (udl->urbs.count * size < wanted_size) {
                unode = kzalloc(sizeof(struct urb_node), GFP_KERNEL);
                if (!unode)
                        break;
@@ -197,11 +202,16 @@ static int udl_alloc_urb_list(struct drm_device *dev, int count, size_t size)
                }
                unode->urb = urb;
 
-               buf = usb_alloc_coherent(udl->udev, MAX_TRANSFER, GFP_KERNEL,
+               buf = usb_alloc_coherent(udl->udev, size, GFP_KERNEL,
                                         &urb->transfer_dma);
                if (!buf) {
                        kfree(unode);
                        usb_free_urb(urb);
+                       if (size > PAGE_SIZE) {
+                               size /= 2;
+                               udl_free_urb_list(dev);
+                               goto retry;
+                       }
                        break;
                }
 
@@ -212,16 +222,14 @@ static int udl_alloc_urb_list(struct drm_device *dev, int count, size_t size)
 
                list_add_tail(&unode->entry, &udl->urbs.list);
 
-               i++;
+               up(&udl->urbs.limit_sem);
+               udl->urbs.count++;
+               udl->urbs.available++;
        }
 
-       sema_init(&udl->urbs.limit_sem, i);
-       udl->urbs.count = i;
-       udl->urbs.available = i;
-
-       DRM_DEBUG("allocated %d %d byte urbs\n", i, (int) size);
+       DRM_DEBUG("allocated %d %d byte urbs\n", udl->urbs.count, (int) size);
 
-       return i;
+       return udl->urbs.count;
 }
 
 struct urb *udl_get_urb(struct drm_device *dev)