2014-01-31 15:09:29

by Alexander Gordeev

[permalink] [raw]
Subject: [PATCH 33/34] 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 <[email protected]>
---
drivers/net/vmxnet3/vmxnet3_drv.c | 101 +++++++++++++++++--------------------
1 files changed, 46 insertions(+), 55 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 3be786f..3a17797 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;
--
1.7.7.6