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From:   Dexuan Cui <decui@microsoft.com>
To:     "'gregkh@linuxfoundation.org'" <gregkh@linuxfoundation.org>,
        KY Srinivasan <kys@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>
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Subject: [PATCH] Drivers: hv: vmbus: Use raw_smp_processor_id() in
 vmbus_connect()
Thread-Topic: [PATCH] Drivers: hv: vmbus: Use raw_smp_processor_id() in
 vmbus_connect()
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Date:   Thu, 23 Aug 2018 20:30:47 +0000
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With CONFIG_DEBUG_PREEMPT=3Dy, I always see this warning:
BUG: using smp_processor_id() in preemptible [00000000]

Fix the false warning by using raw_smp_processor_id().

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
use raw_smp_processor_id() 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>
---
 drivers/hv/connection.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index ced0418..c3b7040 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -119,8 +119,8 @@ static int vmbus_negotiate_version(struct vmbus_channel=
_msginfo *msginfo,
 	 */
 	if (version >=3D VERSION_WIN8_1) {
 		msg->target_vcpu =3D
-			hv_cpu_number_to_vp_number(smp_processor_id());
-		vmbus_connection.connect_cpu =3D smp_processor_id();
+			hv_cpu_number_to_vp_number(raw_smp_processor_id());
+		vmbus_connection.connect_cpu =3D raw_smp_processor_id();
 	} else {
 		msg->target_vcpu =3D 0;
 		vmbus_connection.connect_cpu =3D 0;
--=20
2.7.4