[PATCH] tg3: driver sleeps indefinitely when EEH errors exceed eeh_max_freezes

[David Christensen]

The driver function tg3_io_error_detected() calls napi_disable twice,
without an intervening napi_enable, when the number of EEH errors exceeds
eeh_max_freezes, resulting in an indefinite sleep while holding rtnl_lock.

The function is called once with the PCI state pci_channel_io_frozen and
then called again with the state pci_channel_io_perm_failure when the
number of EEH failures in an hour exceeds eeh_max_freezes.

Protecting the calls to napi_enable/napi_disable with a new state
variable prevents the long sleep.

Signed-off-by: David Christensen <d...@linux.vnet.ibm.com>
---
 drivers/net/ethernet/broadcom/tg3.c | 18 +++++++++++++++---
 drivers/net/ethernet/broadcom/tg3.h |  1 +
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c 
b/drivers/net/ethernet/broadcom/tg3.c
index 7a3b22b35238..953f535e0ceb 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -7373,22 +7373,34 @@ static void tg3_napi_disable(struct tg3 *tp)
 {
        int i;
 
+       if (!tp->napi_enabled)
+               return;
+
        for (i = tp->irq_cnt - 1; i >= 0; i--)
                napi_disable(&tp->napi[i].napi);
+
+       tp->napi_enabled = false;
 }
 
 static void tg3_napi_enable(struct tg3 *tp)
 {
        int i;
 
+       if (tp->napi_enabled)
+               return;
+
        for (i = 0; i < tp->irq_cnt; i++)
                napi_enable(&tp->napi[i].napi);
+
+       tp->napi_enabled = true;
 }
 
 static void tg3_napi_init(struct tg3 *tp)
 {
        int i;
 
+       tp->napi_enabled = false;
+
        netif_napi_add(tp->dev, &tp->napi[0].napi, tg3_poll, 64);
        for (i = 1; i < tp->irq_cnt; i++)
                netif_napi_add(tp->dev, &tp->napi[i].napi, tg3_poll_msix, 64);
@@ -7400,6 +7412,8 @@ static void tg3_napi_fini(struct tg3 *tp)
 
        for (i = 0; i < tp->irq_cnt; i++)
                netif_napi_del(&tp->napi[i].napi);
+
+       tp->napi_enabled = false;
 }
 
 static inline void tg3_netif_stop(struct tg3 *tp)
@@ -18194,10 +18208,8 @@ static pci_ers_result_t tg3_io_error_detected(struct 
pci_dev *pdev,
 
 done:
        if (state == pci_channel_io_perm_failure) {
-               if (netdev) {
-                       tg3_napi_enable(tp);
+               if (netdev)
                        dev_close(netdev);
-               }
                err = PCI_ERS_RESULT_DISCONNECT;
        } else {
                pci_disable_device(pdev);
diff --git a/drivers/net/ethernet/broadcom/tg3.h 
b/drivers/net/ethernet/broadcom/tg3.h
index 6953d0546acb..0681f4b9ec79 100644
--- a/drivers/net/ethernet/broadcom/tg3.h
+++ b/drivers/net/ethernet/broadcom/tg3.h
@@ -3430,6 +3430,7 @@ struct tg3 {
        u32                             ape_hb;
        unsigned long                   ape_hb_interval;
        unsigned long                   ape_hb_jiffies;
+       bool                            napi_enabled;
 };
 
 /* Accessor macros for chip and asic attributes
-- 
2.18.2