rb532: Backport fix to resolve oops during korina_restart

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

diff --git a/target/linux/rb532/patches-4.4/100-korina_fix_napi_disable.patch b/target/linux/rb532/patches-4.4/100-korina_fix_napi_disable.patch
new file mode 100644 (file)
index 0000000..3f80e09
--- /dev/null
+++ b/target/linux/rb532/patches-4.4/100-korina_fix_napi_disable.patch
@@ -0,0 +1,56 @@
+From 5833532b49820aa221248f296c207cc50d20ca2d Mon Sep 17 00:00:00 2001
+From: Florian Fainelli <f.fainelli@gmail.com>
+Date: Fri, 23 Dec 2016 19:36:31 -0800
+Subject: [PATCH net] net: korina: Fix NAPI versus resources freeing
+
+Commit beb0babfb77e ("korina: disable napi on close and restart")
+introduced calls to napi_disable() that were missing before,
+unfortunately this leaves a small window during which NAPI has a chance
+to run, yet we just freed resources since korina_free_ring() has been
+called:
+
+Fix this by disabling NAPI first then freeing resource, and make sure
+that we also cancel the restart taks before doing the resource freeing.
+
+Fixes: beb0babfb77e ("korina: disable napi on close and restart")
+Reported-by: Alexandros C. Couloumbis <alex@ozo.com>
+Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
+---
+ drivers/net/ethernet/korina.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/drivers/net/ethernet/korina.c b/drivers/net/ethernet/korina.c
+index cbeea915f026..8037426ec50f 100644
+--- a/drivers/net/ethernet/korina.c
++++ b/drivers/net/ethernet/korina.c
+@@ -900,10 +900,10 @@ static void korina_restart_task(struct work_struct *work)
+                               DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR,
+                               &lp->rx_dma_regs->dmasm);
+ 
+-      korina_free_ring(dev);
+-
+       napi_disable(&lp->napi);
+ 
++      korina_free_ring(dev);
++
+       if (korina_init(dev) < 0) {
+               printk(KERN_ERR "%s: cannot restart device\n", dev->name);
+               return;
+@@ -1064,12 +1064,12 @@ static int korina_close(struct net_device *dev)
+       tmp = tmp | DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR;
+       writel(tmp, &lp->rx_dma_regs->dmasm);
+ 
+-      korina_free_ring(dev);
+-
+       napi_disable(&lp->napi);
+ 
+       cancel_work_sync(&lp->restart_task);
+ 
++      korina_free_ring(dev);
++
+       free_irq(lp->rx_irq, dev);
+       free_irq(lp->tx_irq, dev);
+       free_irq(lp->ovr_irq, dev);
+-- 
+2.9.3
+