From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
We must handle HVMSG_TIMER_EXPIRED messages in the interrupt context
and we offload all the rest to vmbus_on_msg_dpc() tasklet. This functions
loops to see if there are new messages pending. In case we'll ever see
HVMSG_TIMER_EXPIRED message there we're going to lose it as we can't
handle it from there. Avoid looping in vmbus_on_msg_dpc(), we're OK
with handling one message per interrupt.
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Reviewed-by: Radim Kr.má<rkrcmar@xxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
drivers/hv/vmbus_drv.c | 68 +++++++++++++++++++++++------------------------
1 files changed, 33 insertions(+), 35 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 063e5f5..30ea8ad 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -740,51 +740,49 @@ static void vmbus_on_msg_dpc(unsigned long data)
struct vmbus_channel_message_table_entry *entry;
struct onmessage_work_context *ctx;
- while (1) {
- if (msg->header.message_type == HVMSG_NONE)
- /* no msg */
- break;
+ if (msg->header.message_type == HVMSG_NONE)
+ /* no msg */
+ return;
- hdr = (struct vmbus_channel_message_header *)msg->u.payload;
+ hdr = (struct vmbus_channel_message_header *)msg->u.payload;
- if (hdr->msgtype >= CHANNELMSG_COUNT) {
- WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
- goto msg_handled;
- }
+ if (hdr->msgtype >= CHANNELMSG_COUNT) {
+ WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
+ goto msg_handled;
+ }
- entry = &channel_message_table[hdr->msgtype];
- if (entry->handler_type == VMHT_BLOCKING) {
- ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
- if (ctx == NULL)
- continue;
+ entry = &channel_message_table[hdr->msgtype];
+ if (entry->handler_type == VMHT_BLOCKING) {
+ ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
+ if (ctx == NULL)
+ return;
- INIT_WORK(&ctx->work, vmbus_onmessage_work);
- memcpy(&ctx->msg, msg, sizeof(*msg));
+ INIT_WORK(&ctx->work, vmbus_onmessage_work);
+ memcpy(&ctx->msg, msg, sizeof(*msg));
- queue_work(vmbus_connection.work_queue, &ctx->work);
- } else
- entry->message_handler(hdr);
+ queue_work(vmbus_connection.work_queue, &ctx->work);
+ } else
+ entry->message_handler(hdr);
msg_handled:
- msg->header.message_type = HVMSG_NONE;
+ msg->header.message_type = HVMSG_NONE;
+
+ /*
+ * Make sure the write to MessageType (ie set to
+ * HVMSG_NONE) happens before we read the
+ * MessagePending and EOMing. Otherwise, the EOMing
+ * will not deliver any more messages since there is
+ * no empty slot
+ */
+ mb();
+ if (msg->header.message_flags.msg_pending) {
/*
- * Make sure the write to MessageType (ie set to
- * HVMSG_NONE) happens before we read the
- * MessagePending and EOMing. Otherwise, the EOMing
- * will not deliver any more messages since there is
- * no empty slot
+ * This will cause message queue rescan to
+ * possibly deliver another msg from the
+ * hypervisor
*/
- mb();
-
- if (msg->header.message_flags.msg_pending) {
- /*
- * This will cause message queue rescan to
- * possibly deliver another msg from the
- * hypervisor
- */
- wrmsrl(HV_X64_MSR_EOM, 0);
- }
+ wrmsrl(HV_X64_MSR_EOM, 0);
}
}
--
1.7.4.1
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