udlfb: handle allocation failure

Allocations larger than PAGE_ALLOC_COSTLY_ORDER are unreliable and they
may fail anytime. This patch fixes the udlfb 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: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c
index 770c1c8..4ab9034 100644 (file)
--- a/drivers/video/fbdev/udlfb.c
+++ b/drivers/video/fbdev/udlfb.c
@@ -1843,17 +1843,22 @@ static void dlfb_free_urb_list(struct dlfb_data *dlfb)
 
 static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size)
 {
-       int i = 0;
        struct urb *urb;
        struct urb_node *unode;
        char *buf;
+       size_t wanted_size = count * size;
 
        spin_lock_init(&dlfb->urbs.lock);
 
+retry:
        dlfb->urbs.size = size;
        INIT_LIST_HEAD(&dlfb->urbs.list);
 
-       while (i < count) {
+       sema_init(&dlfb->urbs.limit_sem, 0);
+       dlfb->urbs.count = 0;
+       dlfb->urbs.available = 0;
+
+       while (dlfb->urbs.count * size < wanted_size) {
                unode = kzalloc(sizeof(*unode), GFP_KERNEL);
                if (!unode)
                        break;
@@ -1866,11 +1871,16 @@ static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size)
                }
                unode->urb = urb;
 
-               buf = usb_alloc_coherent(dlfb->udev, MAX_TRANSFER, GFP_KERNEL,
+               buf = usb_alloc_coherent(dlfb->udev, size, GFP_KERNEL,
                                         &urb->transfer_dma);
                if (!buf) {
                        kfree(unode);
                        usb_free_urb(urb);
+                       if (size > PAGE_SIZE) {
+                               size /= 2;
+                               dlfb_free_urb_list(dlfb);
+                               goto retry;
+                       }
                        break;
                }
 
@@ -1881,14 +1891,12 @@ static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size)
 
                list_add_tail(&unode->entry, &dlfb->urbs.list);
 
-               i++;
+               up(&dlfb->urbs.limit_sem);
+               dlfb->urbs.count++;
+               dlfb->urbs.available++;
        }
 
-       sema_init(&dlfb->urbs.limit_sem, i);
-       dlfb->urbs.count = i;
-       dlfb->urbs.available = i;
-
-       return i;
+       return dlfb->urbs.count;
 }
 
 static struct urb *dlfb_get_urb(struct dlfb_data *dlfb)