diff options
authorDexuan Cui <decui@microsoft.com>2018-09-17 04:14:54 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-09-30 08:49:55 -0700
commit41e270f6898e7502be9fd6920ee0a108ca259d36 (patch)
parent17b57b1883c1285f3d0dc2266e8f79286a7bef38 (diff)
Drivers: hv: vmbus: Use get/put_cpu() in vmbus_connect()
With CONFIG_DEBUG_PREEMPT=y, I always see this warning: BUG: using smp_processor_id() in preemptible [00000000] Fix the false warning by using get/put_cpu(). Here vmbus_connect() sends a message to the host and waits for the host's response. The host will deliver the response message and an interrupt on CPU msg->target_vcpu, and later the interrupt handler will wake up vmbus_connect(). vmbus_connect() doesn't really have to run on the same cpu as CPU msg->target_vcpu, so it's safe to call put_cpu() just here. Signed-off-by: Dexuan Cui <decui@microsoft.com> Cc: stable@vger.kernel.org Cc: K. Y. Srinivasan <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index ced041899456..f4d08c8ac7f8 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -76,6 +76,7 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
__u32 version)
int ret = 0;
+ unsigned int cur_cpu;
struct vmbus_channel_initiate_contact *msg;
unsigned long flags;
@@ -118,9 +119,10 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
* the CPU attempting to connect may not be CPU 0.
if (version >= VERSION_WIN8_1) {
- msg->target_vcpu =
- hv_cpu_number_to_vp_number(smp_processor_id());
- vmbus_connection.connect_cpu = smp_processor_id();
+ cur_cpu = get_cpu();
+ msg->target_vcpu = hv_cpu_number_to_vp_number(cur_cpu);
+ vmbus_connection.connect_cpu = cur_cpu;
+ put_cpu();
} else {
msg->target_vcpu = 0;
vmbus_connection.connect_cpu = 0;