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    Subject[PATCH 4.18 126/145] udlfb: handle allocation failure
    Date
    4.18-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Mikulas Patocka <mpatocka@redhat.com>

    commit 080fb5240bdcabed7387b814139c3ea172d59fc5 upstream.

    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>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/video/fbdev/udlfb.c | 26 +++++++++++++++++---------
    1 file changed, 17 insertions(+), 9 deletions(-)

    --- a/drivers/video/fbdev/udlfb.c
    +++ b/drivers/video/fbdev/udlfb.c
    @@ -1843,17 +1843,22 @@ static void dlfb_free_urb_list(struct dl

    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 dl
    }
    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 dl

    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)

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