Drivers: hv: vmbus: Introduce table of VMBus protocol versions

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>
This commit is contained in:
Andrea Parri 2019-10-15 13:46:44 +02:00 committed by Sasha Levin
parent a99d8080aa
commit bedc61a922
3 changed files with 19 additions and 38 deletions

View File

@ -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",

View File

@ -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;
}

View File

@ -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)