[PATCH 5/5 net-next] ibmvnic: Do not attempt to login if RX or TX queues are not allocated

[Thomas Falcon]

If a device reset fails for some reason, TX and RX queue resources
could be released. If a user attempts to open the device in this scenario,
it may result in a kernel panic as the driver tries to access this
memory. To fix this, include a check before device login that TX/RX
queues are still there before enabling the device. In addition, return a
value that can be checked in case of any errors to avoid waiting for a
completion that will never come.

Signed-off-by: Thomas Falcon <tlfal...@linux.vnet.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c 
b/drivers/net/ethernet/ibm/ibmvnic.c
index 53b2c91fa786..765407179fdd 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -111,7 +111,7 @@ static int ibmvnic_poll(struct napi_struct *napi, int data);
 static void send_map_query(struct ibmvnic_adapter *adapter);
 static void send_request_map(struct ibmvnic_adapter *, dma_addr_t, __be32, u8);
 static void send_request_unmap(struct ibmvnic_adapter *, u8);
-static void send_login(struct ibmvnic_adapter *adapter);
+static int send_login(struct ibmvnic_adapter *adapter);
 static void send_cap_queries(struct ibmvnic_adapter *adapter);
 static int init_sub_crqs(struct ibmvnic_adapter *);
 static int init_sub_crq_irqs(struct ibmvnic_adapter *adapter);
@@ -809,8 +809,11 @@ static int ibmvnic_login(struct net_device *netdev)
                }
 
                reinit_completion(&adapter->init_done);
-               send_login(adapter);
-               if (!wait_for_completion_timeout(&adapter->init_done,
+               rc = send_login(adapter);
+               if (rc) {
+                       dev_err(dev, "Unable to attempt device login\n");
+                       return rc;
+               } else if (!wait_for_completion_timeout(&adapter->init_done,
                                                 timeout)) {
                        dev_err(dev, "Login timeout\n");
                        return -1;
@@ -3074,7 +3077,7 @@ static void vnic_add_client_data(struct ibmvnic_adapter 
*adapter,
        strncpy(&vlcd->name, adapter->netdev->name, len);
 }
 
-static void send_login(struct ibmvnic_adapter *adapter)
+static int send_login(struct ibmvnic_adapter *adapter)
 {
        struct ibmvnic_login_rsp_buffer *login_rsp_buffer;
        struct ibmvnic_login_buffer *login_buffer;
@@ -3090,6 +3093,12 @@ static void send_login(struct ibmvnic_adapter *adapter)
        struct vnic_login_client_data *vlcd;
        int i;
 
+       if (!adapter->tx_scrq || !adapter->rx_scrq) {
+               netdev_err(adapter->netdev,
+                          "RX or TX queues are not allocated, device login 
failed\n");
+               return -1;
+       }
+
        release_login_rsp_buffer(adapter);
        client_data_len = vnic_client_data_len(adapter);
 
@@ -3187,7 +3196,7 @@ static void send_login(struct ibmvnic_adapter *adapter)
        crq.login.len = cpu_to_be32(buffer_size);
        ibmvnic_send_crq(adapter, &crq);
 
-       return;
+       return 0;
 
 buf_rsp_map_failed:
        kfree(login_rsp_buffer);
@@ -3196,7 +3205,7 @@ static void send_login(struct ibmvnic_adapter *adapter)
 buf_map_failed:
        kfree(login_buffer);
 buf_alloc_failed:
-       return;
+       return -1;
 }
 
 static void send_request_map(struct ibmvnic_adapter *adapter, dma_addr_t addr,
-- 
2.15.0