From 7be3e169444d2c625f15a0b6639252b98d1f226a Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Fri, 26 Feb 2016 15:13:15 -0800 Subject: [PATCH] Drivers: hv: vmbus: don't loose HVMSG_TIMER_EXPIRED messages MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Radim Kr.má Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/vmbus_drv.c | 68 ++++++++++++++++++++---------------------- 1 file changed, 33 insertions(+), 35 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 063e5f53ca78..30ea8ad902e2 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); } } -- 2.20.1