vmxnet3: Fix MSI-X/MSI enablement code

This update cleans up the MSI-X/MSI enablement code, fixes
vmxnet3_acquire_msix_vectors() invalid return values and
enables a dead code in case VMXNET3_LINUX_MIN_MSIX_VECT
MSI-X vectors were allocated.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Cc: Shreyas Bhatewara <sbhatewara@vmware.com>
Cc: pv-drivers@vmware.com
Cc: netdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 3be786faaaec222f0226b8285dde01e88b147e59..3a17797e08171cd8aae3ccc5fb65b0acee1abdb4 100644 (file)
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -2729,47 +2729,44 @@ vmxnet3_read_mac_addr(struct vmxnet3_adapter *adapter, u8 *mac)
 /*
  * Enable MSIx vectors.
  * Returns :
- *     0 on successful enabling of required vectors,
  *     VMXNET3_LINUX_MIN_MSIX_VECT when only minimum number of vectors required
- *      could be enabled.
- *     number of vectors which can be enabled otherwise (this number is smaller
+ *      were enabled.
+ *     number of vectors which were enabled otherwise (this number is greater
  *      than VMXNET3_LINUX_MIN_MSIX_VECT)
  */
 
 static int
-vmxnet3_acquire_msix_vectors(struct vmxnet3_adapter *adapter,
-                            int vectors)
+vmxnet3_acquire_msix_vectors(struct vmxnet3_adapter *adapter, int nvec)
 {
-       int err = 0, vector_threshold;
-       vector_threshold = VMXNET3_LINUX_MIN_MSIX_VECT;
-
-       while (vectors >= vector_threshold) {
-               err = pci_enable_msix(adapter->pdev, adapter->intr.msix_entries,
-                                     vectors);
+       do {
+               int err = pci_enable_msix(adapter->pdev,
+                                         adapter->intr.msix_entries, nvec);
                if (!err) {
-                       adapter->intr.num_intrs = vectors;
-                       return 0;
+                       return nvec;
                } else if (err < 0) {
                        dev_err(&adapter->netdev->dev,
-                                  "Failed to enable MSI-X, error: %d\n", err);
-                       vectors = 0;
-               } else if (err < vector_threshold) {
-                       break;
+                               "Failed to enable MSI-X, error: %d\n", err);
+                       return err;
+               } else if (err < VMXNET3_LINUX_MIN_MSIX_VECT) {
+                       dev_info(&adapter->pdev->dev,
+                                "Number of MSI-X which can be allocated "
+                                "is lower than min threshold required.\n");
+                       return -ENOSPC;
                } else {
                        /* If fails to enable required number of MSI-x vectors
                         * try enabling minimum number of vectors required.
                         */
                        dev_err(&adapter->netdev->dev,
-                               "Failed to enable %d MSI-X, trying %d instead\n",
-                                   vectors, vector_threshold);
-                       vectors = vector_threshold;
+                               "Failed to enable %d MSI-X, trying %d\n",
+                               nvec, VMXNET3_LINUX_MIN_MSIX_VECT);
+                       nvec = VMXNET3_LINUX_MIN_MSIX_VECT;
                }
-       }
+       } while (nvec >= VMXNET3_LINUX_MIN_MSIX_VECT);
 
-       dev_info(&adapter->pdev->dev,
-                "Number of MSI-X interrupts which can be allocated "
-                "is lower than min threshold required.\n");
-       return err;
+       /*
+        * Should never get here
+        */
+       return -ENOSPC;
 }
 
 
@@ -2796,56 +2793,50 @@ vmxnet3_alloc_intr_resources(struct vmxnet3_adapter *adapter)
 
 #ifdef CONFIG_PCI_MSI
        if (adapter->intr.type == VMXNET3_IT_MSIX) {
-               int vector, err = 0;
-
-               adapter->intr.num_intrs = (adapter->share_intr ==
-                                          VMXNET3_INTR_TXSHARE) ? 1 :
-                                          adapter->num_tx_queues;
-               adapter->intr.num_intrs += (adapter->share_intr ==
-                                          VMXNET3_INTR_BUDDYSHARE) ? 0 :
-                                          adapter->num_rx_queues;
-               adapter->intr.num_intrs += 1;           /* for link event */
-
-               adapter->intr.num_intrs = (adapter->intr.num_intrs >
-                                          VMXNET3_LINUX_MIN_MSIX_VECT
-                                          ? adapter->intr.num_intrs :
-                                          VMXNET3_LINUX_MIN_MSIX_VECT);
-
-               for (vector = 0; vector < adapter->intr.num_intrs; vector++)
-                       adapter->intr.msix_entries[vector].entry = vector;
-
-               err = vmxnet3_acquire_msix_vectors(adapter,
-                                                  adapter->intr.num_intrs);
+               int i, nvec;
+
+               nvec  = adapter->share_intr == VMXNET3_INTR_TXSHARE ?
+                       1 : adapter->num_tx_queues;
+               nvec += adapter->share_intr == VMXNET3_INTR_BUDDYSHARE ?
+                       0 : adapter->num_rx_queues;
+               nvec += 1;      /* for link event */
+               nvec = nvec > VMXNET3_LINUX_MIN_MSIX_VECT ?
+                      nvec : VMXNET3_LINUX_MIN_MSIX_VECT;
+
+               for (i = 0; i < nvec; i++)
+                       adapter->intr.msix_entries[i].entry = i;
+
+               nvec = vmxnet3_acquire_msix_vectors(adapter, nvec);
+               if (nvec < 0)
+                       goto msix_err;
+
                /* If we cannot allocate one MSIx vector per queue
                 * then limit the number of rx queues to 1
                 */
-               if (err == VMXNET3_LINUX_MIN_MSIX_VECT) {
+               if (nvec == VMXNET3_LINUX_MIN_MSIX_VECT) {
                        if (adapter->share_intr != VMXNET3_INTR_BUDDYSHARE
                            || adapter->num_rx_queues != 1) {
                                adapter->share_intr = VMXNET3_INTR_TXSHARE;
                                netdev_err(adapter->netdev,
                                           "Number of rx queues : 1\n");
                                adapter->num_rx_queues = 1;
-                               adapter->intr.num_intrs =
-                                               VMXNET3_LINUX_MIN_MSIX_VECT;
                        }
-                       return;
                }
-               if (!err)
-                       return;
 
+               adapter->intr.num_intrs = nvec;
+               return;
+
+msix_err:
                /* If we cannot allocate MSIx vectors use only one rx queue */
                dev_info(&adapter->pdev->dev,
                         "Failed to enable MSI-X, error %d. "
-                        "Limiting #rx queues to 1, try MSI.\n", err);
+                        "Limiting #rx queues to 1, try MSI.\n", nvec);
 
                adapter->intr.type = VMXNET3_IT_MSI;
        }
 
        if (adapter->intr.type == VMXNET3_IT_MSI) {
-               int err;
-               err = pci_enable_msi(adapter->pdev);
-               if (!err) {
+               if (!pci_enable_msi(adapter->pdev)) {
                        adapter->num_rx_queues = 1;
                        adapter->intr.num_intrs = 1;
                        return;