ibmvnic: Make CRQ interrupt tasklet wait for all capabilities crqs

After sending device capability queries and requests to the vNIC Server,
an interrupt is triggered and the responses are written to the driver's
CRQ response buffer. Since the interrupt can be triggered before all
responses are written and visible to the partition, there is a danger
that the interrupt handler or tasklet can terminate before all responses
are read, resulting in a failure to initialize the device.

To avoid this scenario, when capability commands are sent, we set
a flag that will be checked in the following interrupt tasklet that
will handle the capability responses from the server. Once all
responses have been handled, the flag is disabled; and the tasklet
is allowed to terminate.

Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index b9fbc2dd47cf88f9d589a0ba9c31c6b6de66e3d2..9198e6bd5160f9559075f348a6d595252ea88819 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2418,6 +2418,7 @@ static void handle_request_cap_rsp(union ibmvnic_crq *crq,
                struct ibmvnic_query_ip_offload_buffer *ip_offload_buf =
                    &adapter->ip_offload_buf;
 
+               adapter->wait_capability = false;
                adapter->ip_offload_tok = dma_map_single(dev, ip_offload_buf,
                                                         buf_sz,
                                                         DMA_FROM_DEVICE);
@@ -2713,9 +2714,11 @@ static void handle_query_cap_rsp(union ibmvnic_crq *crq,
        }
 
 out:
-       if (atomic_read(&adapter->running_cap_crqs) == 0)
+       if (atomic_read(&adapter->running_cap_crqs) == 0) {
+               adapter->wait_capability = false;
                init_sub_crqs(adapter, 0);
                /* We're done querying the capabilities, initialize sub-crqs */
+       }
 }
 
 static void handle_control_ras_rsp(union ibmvnic_crq *crq,
@@ -3458,9 +3461,18 @@ static void ibmvnic_tasklet(void *data)
                        ibmvnic_handle_crq(crq, adapter);
                        crq->generic.first = 0;
                } else {
-                       done = true;
+                       /* remain in tasklet until all
+                        * capabilities responses are received
+                        */
+                       if (!adapter->wait_capability)
+                               done = true;
                }
        }
+       /* if capabilities CRQ's were sent in this tasklet, the following
+        * tasklet must wait until all responses are received
+        */
+       if (atomic_read(&adapter->running_cap_crqs) != 0)
+               adapter->wait_capability = true;
        spin_unlock_irqrestore(&queue->lock, flags);
 }
 

diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index 504d05c452e6224ce1d021a68b9e568bcf1d00b7..422824f1f42a8accdbbe7a97c70baa9882fbcce8 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -977,6 +977,7 @@ struct ibmvnic_adapter {
        int login_rsp_buf_sz;
 
        atomic_t running_cap_crqs;
+       bool wait_capability;
 
        struct ibmvnic_sub_crq_queue **tx_scrq;
        struct ibmvnic_sub_crq_queue **rx_scrq;