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).

Andrea Parri committed 7 years ago

Commit bedc61a1 parent a99d8083 files · +19 −38Browse files

Unified · Split

3 files

drivers/hv/connection.c +18 −32
drivers/hv/vmbus_drv.c +1 −2
include/linux/hyperv.h +0 −4

drivers/hv/connection.c+18−32

@@ -40,29 +40,17 @@ EXPORT_SYMBOL_GPL(vmbus_connection); · 39 unmodified lines
40	40	__u32 vmbus_proto_version;
41	41	EXPORT_SYMBOL_GPL(vmbus_proto_version);
42	42
43		−static __u32 vmbus_get_next_version(__u32 current_version)
44		−{
45		− switch (current_version) {
46		− case (VERSION_WIN7):
47		− return VERSION_WS2008;
48		−
49		− case (VERSION_WIN8):
50		− return VERSION_WIN7;
51		−
52		− case (VERSION_WIN8_1):
53		− return VERSION_WIN8;
54		−
55		− case (VERSION_WIN10):
56		− return VERSION_WIN8_1;
57		−
58		− case (VERSION_WIN10_V5):
59		− return VERSION_WIN10;
60		−
61		− case (VERSION_WS2008):
62		− default:
63		− return VERSION_INVAL;
64		− }
65		−}
	43	+/*
	44	+ * Table of VMBus versions listed from newest to oldest.
	45	+ */
	46	+static __u32 vmbus_versions[] = {
	47	+ VERSION_WIN10_V5,
	48	+ VERSION_WIN10,
	49	+ VERSION_WIN8_1,
	50	+ VERSION_WIN8,
	51	+ VERSION_WIN7,
	52	+ VERSION_WS2008
	53	+};
66	54
67	55	int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
68	56	{
@@ -169,8 +157,8 @@ int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version) · 100 unmodified lines
169	157	*/
170	158	int vmbus_connect(void)
171	159	{
172		− int ret = 0;
173	160	struct vmbus_channel_msginfo *msginfo = NULL;
	161	+ int i, ret = 0;
174	162	__u32 version;
175	163
176	164	/* Initialize the vmbus connection */
@@ -244,21 +232,19 @@ int vmbus_connect(void) · 67 unmodified lines
244	232	* version.
245	233	*/
246	234
247		− version = VERSION_CURRENT;
	235	+ for (i = 0; ; i++) {
	236	+ if (i == ARRAY_SIZE(vmbus_versions))
	237	+ goto cleanup;
	238	+
	239	+ version = vmbus_versions[i];
248	240
249		− do {
250	241	ret = vmbus_negotiate_version(msginfo, version);
251	242	if (ret == -ETIMEDOUT)
252	243	goto cleanup;
253	244
254	245	if (vmbus_connection.conn_state == CONNECTED)
255	246	break;
256		−
257		− version = vmbus_get_next_version(version);
258		− } while (version != VERSION_INVAL);
259		−
260		− if (version == VERSION_INVAL)
261		− goto cleanup;
	247	+ }
262	248
263	249	vmbus_proto_version = version;
264	250	pr_info("Vmbus version:%d.%d\n",

drivers/hv/vmbus_drv.c+1−2

@@ -2220,8 +2220,7 @@ static int vmbus_bus_resume(struct device *dev) · 2219 unmodified lines
2220	2220	* We only use the 'vmbus_proto_version', which was in use before
2221	2221	* hibernation, to re-negotiate with the host.
2222	2222	*/
2223		− if (vmbus_proto_version == VERSION_INVAL \|\|
2224		− vmbus_proto_version == 0) {
	2223	+ if (!vmbus_proto_version) {
2225	2224	pr_err("Invalid proto version = 0x%x\n", vmbus_proto_version);
2226	2225	return -EINVAL;
2227	2226	}

include/linux/hyperv.h+0−4

@@ -192,10 +192,6 @@ static inline u32 hv_get_avail_to_write_percent( · 191 unmodified lines
192	192	#define VERSION_WIN10 ((4 << 16) \| (0))
193	193	#define VERSION_WIN10_V5 ((5 << 16) \| (0))
194	194
195		−#define VERSION_INVAL -1
196		−
197		−#define VERSION_CURRENT VERSION_WIN10_V5
198		−
199	195	/* Make maximum size of pipe payload of 16K */
200	196	#define MAX_PIPE_DATA_PAYLOAD (sizeof(u8) * 16384)
201	197

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

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