5.10-stable review patch. If anyone has any objections, please let me know.
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From: Saurabh Sengar ssengar@linux.microsoft.com
[ Upstream commit e8c4bd6c6e6b7e7b416c42806981c2a81370001e ]
Add a function to query for the preferred ring buffer size of VMBus device. This will allow the drivers (eg. UIO) to allocate the most optimized ring buffer size for devices.
Signed-off-by: Saurabh Sengar ssengar@linux.microsoft.com Reviewed-by: Long Li longli@microsoft.com Link: https://lore.kernel.org/r/1711788723-8593-2-git-send-email-ssengar@linux.mic... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Stable-dep-of: 0315fef2aff9 ("uio_hv_generic: Align ring size to system page") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hv/channel_mgmt.c | 15 ++++++++++++--- drivers/hv/hyperv_vmbus.h | 5 +++++ include/linux/hyperv.h | 2 ++ 3 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 4ee8b9b22bb9d..8300ffb1ea9ae 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -106,7 +106,9 @@ const struct vmbus_device vmbus_devs[] = { },
/* File copy */ - { .dev_type = HV_FCOPY, + /* fcopy always uses 16KB ring buffer size and is working well for last many years */ + { .pref_ring_size = 0x4000, + .dev_type = HV_FCOPY, HV_FCOPY_GUID, .perf_device = false, }, @@ -123,11 +125,18 @@ const struct vmbus_device vmbus_devs[] = { .perf_device = false, },
- /* Unknown GUID */ - { .dev_type = HV_UNKNOWN, + /* + * Unknown GUID + * 64 KB ring buffer + 4 KB header should be sufficient size for any Hyper-V device apart + * from HV_NIC and HV_SCSI. This case avoid the fallback for unknown devices to allocate + * much bigger (2 MB) of ring size. + */ + { .pref_ring_size = 0x11000, + .dev_type = HV_UNKNOWN, .perf_device = false, }, }; +EXPORT_SYMBOL_GPL(vmbus_devs);
static const struct { guid_t guid; diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index 323c56152fa1b..1137c25d9a7ae 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -406,6 +406,11 @@ static inline bool hv_is_perf_channel(struct vmbus_channel *channel) return vmbus_devs[channel->device_id].perf_device; }
+static inline size_t hv_dev_ring_size(struct vmbus_channel *channel) +{ + return vmbus_devs[channel->device_id].pref_ring_size; +} + static inline bool hv_is_allocated_cpu(unsigned int cpu) { struct vmbus_channel *channel, *sc; diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 5e019d26b5b72..987cc04f13182 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -802,6 +802,8 @@ struct vmbus_requestor { #define VMBUS_RQST_ID_NO_RESPONSE (U64_MAX - 2)
struct vmbus_device { + /* preferred ring buffer size in KB, 0 means no preferred size for this device */ + size_t pref_ring_size; u16 dev_type; guid_t guid; bool perf_device;