2020-06-17 16:50:10

by Andrea Parri

Subject: [PATCH 1/8] Drivers: hv: vmbus: Remove the target_vp field from the vmbus_channel struct

The field is read only in __vmbus_open() and it is already stored twice
(after a call to hv_cpu_number_to_vp_number()) in target_cpu_store() and
init_vp_index(); there is no need to "cache" its value in the channel
data structure.

Suggested-by: Michael Kelley <[email protected]>
Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
---
drivers/hv/channel.c | 3 ++-
drivers/hv/channel_mgmt.c | 3 ---
drivers/hv/vmbus_drv.c | 2 --
include/linux/hyperv.h | 15 +++++++--------
4 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 90070b337c10d..8848d1548b3f2 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -18,6 +18,7 @@
#include <linux/uio.h>
#include <linux/interrupt.h>
#include <asm/page.h>
+#include <asm/mshyperv.h>

#include "hyperv_vmbus.h"

@@ -176,7 +177,7 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
open_msg->child_relid = newchannel->offermsg.child_relid;
open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
open_msg->downstream_ringbuffer_pageoffset = newchannel->ringbuffer_send_offset;
- open_msg->target_vp = newchannel->target_vp;
+ open_msg->target_vp = hv_cpu_number_to_vp_number(newchannel->target_cpu);

if (userdatalen)
memcpy(open_msg->userdata, userdata, userdatalen);
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 417a95e5094dd..278e392218079 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -704,8 +704,6 @@ static void init_vp_index(struct vmbus_channel *channel)
*/
channel->numa_node = cpu_to_node(VMBUS_CONNECT_CPU);
channel->target_cpu = VMBUS_CONNECT_CPU;
- channel->target_vp =
- hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
if (perf_chn)
hv_set_alloced_cpu(VMBUS_CONNECT_CPU);
return;
@@ -739,7 +737,6 @@ static void init_vp_index(struct vmbus_channel *channel)
cpumask_set_cpu(target_cpu, alloced_mask);

channel->target_cpu = target_cpu;
- channel->target_vp = hv_cpu_number_to_vp_number(target_cpu);

free_cpumask_var(available_mask);
}
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 47747755d2e1d..7e244727f5686 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -23,7 +23,6 @@
#include <linux/cpu.h>
#include <linux/sched/task_stack.h>

-#include <asm/mshyperv.h>
#include <linux/delay.h>
#include <linux/notifier.h>
#include <linux/ptrace.h>
@@ -1765,7 +1764,6 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel,
*/

channel->target_cpu = target_cpu;
- channel->target_vp = hv_cpu_number_to_vp_number(target_cpu);
channel->numa_node = cpu_to_node(target_cpu);

/* See init_vp_index(). */
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 40df3103e890b..738efdb194b09 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -803,15 +803,14 @@ struct vmbus_channel {
u64 sig_event;

/*
- * Starting with win8, this field will be used to specify
- * the target virtual processor on which to deliver the interrupt for
- * the host to guest communication.
- * Prior to win8, incoming channel interrupts would only
- * be delivered on cpu 0. Setting this value to 0 would
- * preserve the earlier behavior.
+ * Starting with win8, this field will be used to specify the
+ * target CPU on which to deliver the interrupt for the host
+ * to guest communication.
+ *
+ * Prior to win8, incoming channel interrupts would only be
+ * delivered on CPU 0. Setting this value to 0 would preserve
+ * the earlier behavior.
*/
- u32 target_vp;
- /* The corresponding CPUID in the guest */
u32 target_cpu;
int numa_node;
/*
--
2.25.1

2020-06-18 15:27:18

by Michael Kelley (LINUX)

Subject: RE: [PATCH 1/8] Drivers: hv: vmbus: Remove the target_vp field from the vmbus_channel struct

From: Andrea Parri (Microsoft) <[email protected]> Sent: Wednesday, June 17, 2020 9:47 AM
>
> The field is read only in __vmbus_open() and it is already stored twice
> (after a call to hv_cpu_number_to_vp_number()) in target_cpu_store() and
> init_vp_index(); there is no need to "cache" its value in the channel
> data structure.
>
> Suggested-by: Michael Kelley <[email protected]>
> Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
> ---
> drivers/hv/channel.c | 3 ++-
> drivers/hv/channel_mgmt.c | 3 ---
> drivers/hv/vmbus_drv.c | 2 --
> include/linux/hyperv.h | 15 +++++++--------
> 4 files changed, 9 insertions(+), 14 deletions(-)

Reviewed-by: Michael Kelley <[email protected]>