Commit bedc61a9 authored by Andrea Parri's avatar Andrea Parri Committed by Sasha Levin
Browse files

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: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarAndrea Parri <parri.andrea@gmail.com>
Reviewed-by: default avatarWei Liu <wei.liu@kernel.org>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent a99d8080

drivers/hv/connection.c

+18 −32
Original line number Diff line number Diff line
@@ -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",

drivers/hv/vmbus_drv.c

+1 −2
Original line number Diff line number Diff line
@@ -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;

	}

include/linux/hyperv.h

+0 −4
Original line number Diff line number Diff line
@@ -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)

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