cxgb4: fix BUG() on interrupt deallocating path of ULD

Since the introduction of ULD (Upper-Layer Drivers), the MSI-X
deallocating path changed in cxgb4: the driver frees the interrupts
of ULD when unregistering it or on shutdown PCI handler.

Problem is that if a MSI-X is not freed before deallocated in the PCI
layer, it will trigger a BUG() due to still "alive" interrupt being
tentatively quiesced.

The below trace was observed when doing a simple unbind of Chelsio's
adapter PCI function, like:
  "echo 001e:80:00.4 > /sys/bus/pci/drivers/cxgb4/unbind"

Trace:

  kernel BUG at drivers/pci/msi.c:352!
  Oops: Exception in kernel mode, sig: 5 [#1]
  ...
  NIP [c0000000005a5e60] free_msi_irqs+0xa0/0x250
  LR [c0000000005a5e50] free_msi_irqs+0x90/0x250
  Call Trace:
  [c0000000005a5e50] free_msi_irqs+0x90/0x250 (unreliable)
  [c0000000005a72c4] pci_disable_msix+0x124/0x180
  [d000000011e06708] disable_msi+0x88/0xb0 [cxgb4]
  [d000000011e06948] free_some_resources+0xa8/0x160 [cxgb4]
  [d000000011e06d60] remove_one+0x170/0x3c0 [cxgb4]
  [c00000000058a910] pci_device_remove+0x70/0x110
  [c00000000064ef04] device_release_driver_internal+0x1f4/0x2c0
  ...

This patch fixes the issue by refactoring the shutdown path of ULD on
cxgb4 driver, by properly freeing and disabling interrupts on PCI
remove handler too.

Fixes: 0fbc81b3ad51 ("Allocate resources dynamically for all cxgb4 ULD's")
Reported-by: Harsha Thyagaraja <hathyaga@in.ibm.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index 86f92e31e8aa6bc042e97aa131da01bb17765a44..e403fa18f1b15e570748b2136ae1bf8b54d14afb 100644 (file)
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -2083,12 +2083,12 @@ static void detach_ulds(struct adapter *adap)
 
        mutex_lock(&uld_mutex);
        list_del(&adap->list_node);
+
        for (i = 0; i < CXGB4_ULD_MAX; i++)
-               if (adap->uld && adap->uld[i].handle) {
+               if (adap->uld && adap->uld[i].handle)
                        adap->uld[i].state_change(adap->uld[i].handle,
                                             CXGB4_STATE_DETACH);
-                       adap->uld[i].handle = NULL;
-               }
+
        if (netevent_registered && list_empty(&adapter_list)) {
                unregister_netevent_notifier(&cxgb4_netevent_nb);
                netevent_registered = false;
@@ -5303,8 +5303,10 @@ static void remove_one(struct pci_dev *pdev)
                 */
                destroy_workqueue(adapter->workq);
 
-               if (is_uld(adapter))
+               if (is_uld(adapter)) {
                        detach_ulds(adapter);
+                       t4_uld_clean_up(adapter);
+               }
 
                disable_interrupts(adapter);
 
@@ -5385,7 +5387,11 @@ static void shutdown_one(struct pci_dev *pdev)
                        if (adapter->port[i]->reg_state == NETREG_REGISTERED)
                                cxgb_close(adapter->port[i]);
 
-               t4_uld_clean_up(adapter);
+               if (is_uld(adapter)) {
+                       detach_ulds(adapter);
+                       t4_uld_clean_up(adapter);
+               }
+
                disable_interrupts(adapter);
                disable_msi(adapter);
 

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c
index ec53fe9dec6887369f3d97c0b67e305bf6906749..71a315bc14097908aba2f8f7437759a7445778cb 100644 (file)
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c
@@ -589,22 +589,37 @@ void t4_uld_mem_free(struct adapter *adap)
        kfree(adap->uld);
 }
 
+/* This function should be called with uld_mutex taken. */
+static void cxgb4_shutdown_uld_adapter(struct adapter *adap, enum cxgb4_uld type)
+{
+       if (adap->uld[type].handle) {
+               adap->uld[type].handle = NULL;
+               adap->uld[type].add = NULL;
+               release_sge_txq_uld(adap, type);
+
+               if (adap->flags & FULL_INIT_DONE)
+                       quiesce_rx_uld(adap, type);
+
+               if (adap->flags & USING_MSIX)
+                       free_msix_queue_irqs_uld(adap, type);
+
+               free_sge_queues_uld(adap, type);
+               free_queues_uld(adap, type);
+       }
+}
+
 void t4_uld_clean_up(struct adapter *adap)
 {
        unsigned int i;
 
-       if (!adap->uld)
-               return;
+       mutex_lock(&uld_mutex);
        for (i = 0; i < CXGB4_ULD_MAX; i++) {
                if (!adap->uld[i].handle)
                        continue;
-               if (adap->flags & FULL_INIT_DONE)
-                       quiesce_rx_uld(adap, i);
-               if (adap->flags & USING_MSIX)
-                       free_msix_queue_irqs_uld(adap, i);
-               free_sge_queues_uld(adap, i);
-               free_queues_uld(adap, i);
+
+               cxgb4_shutdown_uld_adapter(adap, i);
        }
+       mutex_unlock(&uld_mutex);
 }
 
 static void uld_init(struct adapter *adap, struct cxgb4_lld_info *lld)
@@ -783,15 +798,8 @@ int cxgb4_unregister_uld(enum cxgb4_uld type)
                        continue;
                if (type == CXGB4_ULD_ISCSIT && is_t4(adap->params.chip))
                        continue;
-               adap->uld[type].handle = NULL;
-               adap->uld[type].add = NULL;
-               release_sge_txq_uld(adap, type);
-               if (adap->flags & FULL_INIT_DONE)
-                       quiesce_rx_uld(adap, type);
-               if (adap->flags & USING_MSIX)
-                       free_msix_queue_irqs_uld(adap, type);
-               free_sge_queues_uld(adap, type);
-               free_queues_uld(adap, type);
+
+               cxgb4_shutdown_uld_adapter(adap, type);
        }
        mutex_unlock(&uld_mutex);