linux-kernel - [PATCH net-next] vmxnet3: fix minimum vectors alloc issue

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Message-ID: <20211207081737.14000-1-doshir@vmware.com>
Date:   Tue, 7 Dec 2021 00:17:37 -0800
From:   Ronak Doshi <doshir@...are.com>
To:     <netdev@...r.kernel.org>
CC:     Ronak Doshi <doshir@...are.com>,
        "maintainer:VMWARE VMXNET3 ETHERNET DRIVER" <pv-drivers@...are.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Guolin Yang <gyang@...are.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: [PATCH net-next] vmxnet3: fix minimum vectors alloc issue

'Commit 39f9895a00f4 ("vmxnet3: add support for 32 Tx/Rx queues")'
added support for 32Tx/Rx queues. Within that patch, value of
VMXNET3_LINUX_MIN_MSIX_VECT was updated.

However, there is a case (numvcpus = 2) which actually requires 3
intrs which matches VMXNET3_LINUX_MIN_MSIX_VECT which then is
treated as failure by stack to allocate more vectors. This patch
fixes this issue.

Fixes: 39f9895a00f4 ("vmxnet3: add support for 32 Tx/Rx queues")
Signed-off-by: Ronak Doshi <doshir@...are.com>
Acked-by: Guolin Yang <gyang@...are.com>
---
 drivers/net/vmxnet3/vmxnet3_drv.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 14fae317bc70..fd407c0e2856 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -3261,7 +3261,7 @@ vmxnet3_alloc_intr_resources(struct vmxnet3_adapter *adapter)
 
 #ifdef CONFIG_PCI_MSI
 	if (adapter->intr.type == VMXNET3_IT_MSIX) {
-		int i, nvec;
+		int i, nvec, nvec_allocated;
 
 		nvec  = adapter->share_intr == VMXNET3_INTR_TXSHARE ?
 			1 : adapter->num_tx_queues;
@@ -3274,14 +3274,15 @@ vmxnet3_alloc_intr_resources(struct vmxnet3_adapter *adapter)
 		for (i = 0; i < nvec; i++)
 			adapter->intr.msix_entries[i].entry = i;
 
-		nvec = vmxnet3_acquire_msix_vectors(adapter, nvec);
-		if (nvec < 0)
+		nvec_allocated = vmxnet3_acquire_msix_vectors(adapter, nvec);
+		if (nvec_allocated < 0)
 			goto msix_err;
 
 		/* If we cannot allocate one MSIx vector per queue
 		 * then limit the number of rx queues to 1
 		 */
-		if (nvec == VMXNET3_LINUX_MIN_MSIX_VECT) {
+		if (nvec_allocated == VMXNET3_LINUX_MIN_MSIX_VECT &&
+		    nvec != VMXNET3_LINUX_MIN_MSIX_VECT) {
 			if (adapter->share_intr != VMXNET3_INTR_BUDDYSHARE
 			    || adapter->num_rx_queues != 1) {
 				adapter->share_intr = VMXNET3_INTR_TXSHARE;
@@ -3291,14 +3292,14 @@ vmxnet3_alloc_intr_resources(struct vmxnet3_adapter *adapter)
 			}
 		}
 
-		adapter->intr.num_intrs = nvec;
+		adapter->intr.num_intrs = nvec_allocated;
 		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", nvec);
+			 "Limiting #rx queues to 1, try MSI.\n", nvec_allocated);
 
 		adapter->intr.type = VMXNET3_IT_MSI;
 	}
-- 
2.11.0