Commit 41e270f6 authored by Dexuan Cui's avatar Dexuan Cui Committed by Greg Kroah-Hartman

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: default avatarDexuan 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: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 17b57b18
...@@ -76,6 +76,7 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, ...@@ -76,6 +76,7 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
__u32 version) __u32 version)
{ {
int ret = 0; int ret = 0;
unsigned int cur_cpu;
struct vmbus_channel_initiate_contact *msg; struct vmbus_channel_initiate_contact *msg;
unsigned long flags; unsigned long flags;
...@@ -118,9 +119,10 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, ...@@ -118,9 +119,10 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
* the CPU attempting to connect may not be CPU 0. * the CPU attempting to connect may not be CPU 0.
*/ */
if (version >= VERSION_WIN8_1) { if (version >= VERSION_WIN8_1) {
msg->target_vcpu = cur_cpu = get_cpu();
hv_cpu_number_to_vp_number(smp_processor_id()); msg->target_vcpu = hv_cpu_number_to_vp_number(cur_cpu);
vmbus_connection.connect_cpu = smp_processor_id(); vmbus_connection.connect_cpu = cur_cpu;
put_cpu();
} else { } else {
msg->target_vcpu = 0; msg->target_vcpu = 0;
vmbus_connection.connect_cpu = 0; vmbus_connection.connect_cpu = 0;
......
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