2017-04-06 22:00:32

by kys

Subject: [PATCH net-next 1/1] netvsc: Initialize all channel related state prior to opening the channel

From: K. Y. Srinivasan <[email protected]>

Prior to opening the channel we should have all the state setup to handle
interrupts. The current code does not do that; fix the bug. This bug
can result in faults in the interrupt path.

Signed-off-by: K. Y. Srinivasan <[email protected]>
---
drivers/net/hyperv/netvsc.c | 27 +++++++++++++++------------
drivers/net/hyperv/rndis_filter.c | 5 +++--
2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index e998e2f..7ab06b3 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -1289,6 +1289,21 @@ int netvsc_device_add(struct hv_device *device,
*/
set_channel_read_mode(device->channel, HV_CALL_ISR);

+ /* If we're reopening the device we may have multiple queues, fill the
+ * chn_table with the default channel to use it before subchannels are
+ * opened.
+ * Initialize the channel state before we open;
+ * we can be interrupted as soon as we open the channel.
+ */
+
+ for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
+ struct netvsc_channel *nvchan = &net_device->chan_table[i];
+
+ nvchan->channel = device->channel;
+ netif_napi_add(ndev, &nvchan->napi,
+ netvsc_poll, NAPI_POLL_WEIGHT);
+ }
+
/* Open the channel */
ret = vmbus_open(device->channel, ring_size * PAGE_SIZE,
ring_size * PAGE_SIZE, NULL, 0,
@@ -1303,18 +1318,6 @@ int netvsc_device_add(struct hv_device *device,
/* Channel is opened */
netdev_dbg(ndev, "hv_netvsc channel opened successfully\n");

- /* If we're reopening the device we may have multiple queues, fill the
- * chn_table with the default channel to use it before subchannels are
- * opened.
- */
- for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
- struct netvsc_channel *nvchan = &net_device->chan_table[i];
-
- nvchan->channel = device->channel;
- netif_napi_add(ndev, &nvchan->napi,
- netvsc_poll, NAPI_POLL_WEIGHT);
- }
-
/* Enable NAPI handler for init callbacks */
napi_enable(&net_device->chan_table[0].napi);

diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 9835825..1e9445b 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1007,12 +1007,13 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
*/
set_channel_read_mode(new_sc, HV_CALL_ISR);

+ /* Set the channel before opening.*/
+ nvchan->channel = new_sc;
+
ret = vmbus_open(new_sc, nvscdev->ring_size * PAGE_SIZE,
nvscdev->ring_size * PAGE_SIZE, NULL, 0,
netvsc_channel_cb, nvchan);

- if (ret == 0)
- nvchan->channel = new_sc;

napi_enable(&nvchan->napi);

--
1.7.1

2017-04-08 15:33:27

by David Miller

Subject: Re: [PATCH net-next 1/1] netvsc: Initialize all channel related state prior to opening the channel

From: [email protected]
Date: Thu, 6 Apr 2017 14:59:21 -0700

> From: K. Y. Srinivasan <[email protected]>
>
> Prior to opening the channel we should have all the state setup to handle
> interrupts. The current code does not do that; fix the bug. This bug
> can result in faults in the interrupt path.
>
> Signed-off-by: K. Y. Srinivasan <[email protected]>

Applied, thanks.