target/linux/rb532/patches-4.4/100-korina_fix_napi_disable.patch

   1 From 5833532b49820aa221248f296c207cc50d20ca2d Mon Sep 17 00:00:00 2001
   2 From: Florian Fainelli <f.fainelli@gmail.com>
   3 Date: Fri, 23 Dec 2016 19:36:31 -0800
   4 Subject: [PATCH net] net: korina: Fix NAPI versus resources freeing
   5
   6 Commit beb0babfb77e ("korina: disable napi on close and restart")
   7 introduced calls to napi_disable() that were missing before,
   8 unfortunately this leaves a small window during which NAPI has a chance
   9 to run, yet we just freed resources since korina_free_ring() has been
  10 called:
  11
  12 Fix this by disabling NAPI first then freeing resource, and make sure
  13 that we also cancel the restart taks before doing the resource freeing.
  14
  15 Fixes: beb0babfb77e ("korina: disable napi on close and restart")
  16 Reported-by: Alexandros C. Couloumbis <alex@ozo.com>
  17 Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
  18 ---
  19  drivers/net/ethernet/korina.c | 8 ++++----
  20  1 file changed, 4 insertions(+), 4 deletions(-)
  21
  22 --- a/drivers/net/ethernet/korina.c
  23 +++ b/drivers/net/ethernet/korina.c
  24 @@ -900,10 +900,10 @@ static void korina_restart_task(struct w
  25                                 DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR,
  26                                 &lp->rx_dma_regs->dmasm);
  27
  28 -       korina_free_ring(dev);
  29 -
  30         napi_disable(&lp->napi);
  31
  32 +       korina_free_ring(dev);
  33 +
  34         if (korina_init(dev) < 0) {
  35                 printk(KERN_ERR "%s: cannot restart device\n", dev->name);
  36                 return;
  37 @@ -1064,12 +1064,12 @@ static int korina_close(struct net_devic
  38         tmp = tmp | DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR;
  39         writel(tmp, &lp->rx_dma_regs->dmasm);
  40
  41 -       korina_free_ring(dev);
  42 -
  43         napi_disable(&lp->napi);
  44
  45         cancel_work_sync(&lp->restart_task);
  46
  47 +       korina_free_ring(dev);
  48 +
  49         free_irq(lp->rx_irq, dev);
  50         free_irq(lp->tx_irq, dev);
  51         free_irq(lp->ovr_irq, dev);