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>

1 files changed, 46 insertions, 55 deletions

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 3be786faaaec..3a17797e0817 100644
--- 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;