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9b0eee15f3
Added a patch to reduce verbosity of vmbus for unknown GUIDs. Thes happen on every Hyper-V socket connection. Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
100 lines
3.1 KiB
Diff
100 lines
3.1 KiB
Diff
From ddf2482b26c0381ab579ed3c4769249ea0f5aacb Mon Sep 17 00:00:00 2001
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From: Vitaly Kuznetsov <vkuznets@redhat.com>
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Date: Wed, 27 Jan 2016 22:29:35 -0800
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Subject: [PATCH 23/41] Drivers: hv: vmbus: avoid scheduling in interrupt
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context in vmbus_initiate_unload()
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We have to call vmbus_initiate_unload() on crash to make kdump work but
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the crash can also be happening in interrupt (e.g. Sysrq + c results in
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such) where we can't schedule or the following will happen:
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[ 314.905786] bad: scheduling from the idle thread!
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Just skipping the wait (and even adding some random wait here) won't help:
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to make host-side magic working we're supposed to receive CHANNELMSG_UNLOAD
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(and actually confirm the fact that we received it) but we can't use
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interrupt-base path (vmbus_isr()-> vmbus_on_msg_dpc()). Implement a simple
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busy wait ignoring all the other messages and use it if we're in an
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interrupt context.
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Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
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Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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(cherry picked from commit 415719160de3fae3bb9cbc617664649919cd00d0)
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---
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drivers/hv/channel_mgmt.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
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1 file changed, 43 insertions(+), 1 deletion(-)
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diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
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index af1d82e..d6c6114 100644
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--- a/drivers/hv/channel_mgmt.c
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+++ b/drivers/hv/channel_mgmt.c
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@@ -28,6 +28,7 @@
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/completion.h>
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+#include <linux/delay.h>
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#include <linux/hyperv.h>
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#include "hyperv_vmbus.h"
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@@ -589,6 +590,40 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
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channel->target_vp = hv_context.vp_index[cur_cpu];
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}
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+static void vmbus_wait_for_unload(void)
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+{
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+ int cpu = smp_processor_id();
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+ void *page_addr = hv_context.synic_message_page[cpu];
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+ struct hv_message *msg = (struct hv_message *)page_addr +
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+ VMBUS_MESSAGE_SINT;
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+ struct vmbus_channel_message_header *hdr;
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+ bool unloaded = false;
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+
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+ while (1) {
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+ if (msg->header.message_type == HVMSG_NONE) {
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+ mdelay(10);
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+ continue;
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+ }
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+
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+ hdr = (struct vmbus_channel_message_header *)msg->u.payload;
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+ if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
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+ unloaded = true;
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+
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+ msg->header.message_type = HVMSG_NONE;
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+ /*
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+ * header.message_type needs to be written before we do
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+ * wrmsrl() below.
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+ */
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+ mb();
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+
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+ if (msg->header.message_flags.msg_pending)
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+ wrmsrl(HV_X64_MSR_EOM, 0);
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+
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+ if (unloaded)
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+ break;
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+ }
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+}
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+
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/*
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* vmbus_unload_response - Handler for the unload response.
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*/
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@@ -614,7 +649,14 @@ void vmbus_initiate_unload(void)
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hdr.msgtype = CHANNELMSG_UNLOAD;
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vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header));
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- wait_for_completion(&vmbus_connection.unload_event);
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+ /*
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+ * vmbus_initiate_unload() is also called on crash and the crash can be
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+ * happening in an interrupt context, where scheduling is impossible.
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+ */
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+ if (!in_interrupt())
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+ wait_for_completion(&vmbus_connection.unload_event);
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+ else
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+ vmbus_wait_for_unload();
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}
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/*
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--
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2.8.2
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