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authorAndrea Parri (Microsoft) <parri.andrea@gmail.com>2020-04-06 03:15:07 +0300
committerWei Liu <wei.liu@kernel.org>2020-04-23 16:17:11 +0300
commitac5047671758ad4be9f93898247b3a8b6dfde4c7 (patch)
tree587b9d5c51dae373418d131019985a46f76ee172
parent8b6a877c060ed6b86878fe66c7c6493a6054cf23 (diff)
downloadlinux-ac5047671758ad4be9f93898247b3a8b6dfde4c7.tar.xz
hv_netvsc: Disable NAPI before closing the VMBus channel
vmbus_chan_sched() might call the netvsc driver callback function that ends up scheduling NAPI work. This "work" can access the channel ring buffer, so we must ensure that any such work is completed and that the ring buffer is no longer being accessed before freeing the ring buffer data structure in the channel closure path. To this end, disable NAPI before calling vmbus_close() in netvsc_device_remove(). Suggested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Acked-by: Stephen Hemminger <stephen@networkplumber.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: <netdev@vger.kernel.org> Link: https://lore.kernel.org/r/20200406001514.19876-5-parri.andrea@gmail.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
-rw-r--r--drivers/hv/channel.c6
-rw-r--r--drivers/net/hyperv/netvsc.c7
2 files changed, 11 insertions, 2 deletions
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 23f358cb7f49..256ee90c7446 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -609,6 +609,12 @@ void vmbus_reset_channel_cb(struct vmbus_channel *channel)
* the former is accessing channel->inbound.ring_buffer, the latter
* could be freeing the ring_buffer pages, so here we must stop it
* first.
+ *
+ * vmbus_chan_sched() might call the netvsc driver callback function
+ * that ends up scheduling NAPI work that accesses the ring buffer.
+ * At this point, we have to ensure that any such work is completed
+ * and that the channel ring buffer is no longer being accessed, cf.
+ * the calls to napi_disable() in netvsc_device_remove().
*/
tasklet_disable(&channel->callback_event);
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index ca68aa1df801..41f5cf0bb997 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -636,9 +636,12 @@ void netvsc_device_remove(struct hv_device *device)
RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
- /* And disassociate NAPI context from device */
- for (i = 0; i < net_device->num_chn; i++)
+ /* Disable NAPI and disassociate its context from the device. */
+ for (i = 0; i < net_device->num_chn; i++) {
+ /* See also vmbus_reset_channel_cb(). */
+ napi_disable(&net_device->chan_table[i].napi);
netif_napi_del(&net_device->chan_table[i].napi);
+ }
/*
* At this point, no one should be accessing net_device