From: Andrea Parri <parri.andrea@gmail.com>
Date: Tue, 15 Oct 2019 13:46:44 +0200
Patch-mainline: v5.5-rc1
Subject: Drivers: hv: vmbus: Introduce table of VMBus protocol versions
Git-commit: bedc61a922f9dbbe3bfb26ec2745f8cd63b57637
References: jsc#sle-12891
The technique used to get the next VMBus version seems increasisly
clumsy as the number of VMBus versions increases. Performance is
not a concern since this is only done once during system boot; it's
just that we'll end up with more lines of code than is really needed.
As an alternative, introduce a table with the version numbers listed
in order (from the most recent to the oldest). vmbus_connect() loops
through the versions listed in the table until it gets an accepted
connection or gets to the end of the table (invalid version).
Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Olaf Hering <ohering@suse.de>
---
drivers/hv/connection.c | 50 ++++++++++++++++++-------------------------------
drivers/hv/vmbus_drv.c | 3 +--
include/linux/hyperv.h | 4 ----
3 files changed, 19 insertions(+), 38 deletions(-)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -40,29 +40,17 @@ EXPORT_SYMBOL_GPL(vmbus_connection);
__u32 vmbus_proto_version;
EXPORT_SYMBOL_GPL(vmbus_proto_version);
-static __u32 vmbus_get_next_version(__u32 current_version)
-{
- switch (current_version) {
- case (VERSION_WIN7):
- return VERSION_WS2008;
-
- case (VERSION_WIN8):
- return VERSION_WIN7;
-
- case (VERSION_WIN8_1):
- return VERSION_WIN8;
-
- case (VERSION_WIN10):
- return VERSION_WIN8_1;
-
- case (VERSION_WIN10_V5):
- return VERSION_WIN10;
-
- case (VERSION_WS2008):
- default:
- return VERSION_INVAL;
- }
-}
+/*
+ * Table of VMBus versions listed from newest to oldest.
+ */
+static __u32 vmbus_versions[] = {
+ VERSION_WIN10_V5,
+ VERSION_WIN10,
+ VERSION_WIN8_1,
+ VERSION_WIN8,
+ VERSION_WIN7,
+ VERSION_WS2008
+};
int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
{
@@ -169,8 +157,8 @@ int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
*/
int vmbus_connect(void)
{
- int ret = 0;
struct vmbus_channel_msginfo *msginfo = NULL;
+ int i, ret = 0;
__u32 version;
/* Initialize the vmbus connection */
@@ -244,21 +232,19 @@ int vmbus_connect(void)
* version.
*/
- version = VERSION_CURRENT;
+ for (i = 0; ; i++) {
+ if (i == ARRAY_SIZE(vmbus_versions))
+ goto cleanup;
+
+ version = vmbus_versions[i];
- do {
ret = vmbus_negotiate_version(msginfo, version);
if (ret == -ETIMEDOUT)
goto cleanup;
if (vmbus_connection.conn_state == CONNECTED)
break;
-
- version = vmbus_get_next_version(version);
- } while (version != VERSION_INVAL);
-
- if (version == VERSION_INVAL)
- goto cleanup;
+ }
vmbus_proto_version = version;
pr_info("Vmbus version:%d.%d\n",
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2220,8 +2220,7 @@ static int vmbus_bus_resume(struct device *dev)
* We only use the 'vmbus_proto_version', which was in use before
* hibernation, to re-negotiate with the host.
*/
- if (vmbus_proto_version == VERSION_INVAL ||
- vmbus_proto_version == 0) {
+ if (!vmbus_proto_version) {
pr_err("Invalid proto version = 0x%x\n", vmbus_proto_version);
return -EINVAL;
}
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -192,10 +192,6 @@ static inline u32 hv_get_avail_to_write_percent(
#define VERSION_WIN10 ((4 << 16) | (0))
#define VERSION_WIN10_V5 ((5 << 16) | (0))
-#define VERSION_INVAL -1
-
-#define VERSION_CURRENT VERSION_WIN10_V5
-
/* Make maximum size of pipe payload of 16K */
#define MAX_PIPE_DATA_PAYLOAD (sizeof(u8) * 16384)