[PATCH v3 1/3] Drivers: hv: vmbus: Introduce table of VMBus protocol versions
From: Andrea Parri <parri.andrea@gmail.com>
Date: 2019-10-15 11:47:20
Also in:
lkml
Subsystem:
hyper-v/azure core and drivers, the rest · Maintainers:
"K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, Linus Torvalds
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 <redacted> Signed-off-by: Andrea Parri <parri.andrea@gmail.com> --- 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
index 6e4c015783ffc..8dc48f53c1ac4 100644
--- 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
index 53a60c81e220d..0ac874faf7209 100644
--- 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
index b4a017093b697..c08b62dbd151f 100644
--- 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)
--
2.23.0