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@xxxxxxxxxxxxx> Signed-off-by: Andrea Parri <parri.andrea@xxxxxxxxx> --- drivers/hv/connection.c | 46 ++++++++++++++--------------------------- drivers/hv/vmbus_drv.c | 3 +-- include/linux/hyperv.h | 4 ---- 3 files changed, 17 insertions(+), 36 deletions(-) diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c index 6e4c015783ffc..b1f805426e6b4 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 */ @@ -244,20 +232,18 @@ int vmbus_connect(void) * version. */ - version = VERSION_CURRENT; + for (i = 0; i < ARRAY_SIZE(vmbus_versions); i++) { + 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) + if (vmbus_connection.conn_state != CONNECTED) goto cleanup; vmbus_proto_version = version; diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 391f0b225c9ae..a0cd65ab9a950 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -2215,8 +2215,7 @@ 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