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authorDexuan Cui <decui@microsoft.com>2019-09-05 23:01:18 +0000
committerSasha Levin <sashal@kernel.org>2019-09-06 14:52:44 -0400
commite3ede02add7e6df315afc6b4120520f7d0c5a258 (patch)
treead419a90173f22a44a040ab17452f1641723f79f /drivers/hv
parent271b2224d42f88870e6b060924ee374871c131fc (diff)
downloadlinux-e3ede02add7e6df315afc6b4120520f7d0c5a258.tar.bz2
Drivers: hv: vmbus: Ignore the offers when resuming from hibernation
When the VM resumes, the host re-sends the offers. We should not add the offers to the global vmbus_connection.chn_list again. This patch assumes the RELIDs of the channels don't change across hibernation. Actually this is not always true, especially in the case of NIC SR-IOV the VF vmbus device's RELID sometimes can change. A later patch will address this issue by mapping the new offers to the old channels and fixing up the old channels, if necessary. Signed-off-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/channel_mgmt.c58
1 files changed, 57 insertions, 1 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index addcef50df7a..44b92fa1b7fa 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -848,18 +848,74 @@ void vmbus_initiate_unload(bool crash)
}
/*
+ * find_primary_channel_by_offer - Get the channel object given the new offer.
+ * This is only used in the resume path of hibernation.
+ */
+static struct vmbus_channel *
+find_primary_channel_by_offer(const struct vmbus_channel_offer_channel *offer)
+{
+ struct vmbus_channel *channel = NULL, *iter;
+ const guid_t *inst1, *inst2;
+
+ /* Ignore sub-channel offers. */
+ if (offer->offer.sub_channel_index != 0)
+ return NULL;
+
+ mutex_lock(&vmbus_connection.channel_mutex);
+
+ list_for_each_entry(iter, &vmbus_connection.chn_list, listentry) {
+ inst1 = &iter->offermsg.offer.if_instance;
+ inst2 = &offer->offer.if_instance;
+
+ if (guid_equal(inst1, inst2)) {
+ channel = iter;
+ break;
+ }
+ }
+
+ mutex_unlock(&vmbus_connection.channel_mutex);
+
+ return channel;
+}
+
+/*
* vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
*
*/
static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
{
struct vmbus_channel_offer_channel *offer;
- struct vmbus_channel *newchannel;
+ struct vmbus_channel *oldchannel, *newchannel;
+ size_t offer_sz;
offer = (struct vmbus_channel_offer_channel *)hdr;
trace_vmbus_onoffer(offer);
+ oldchannel = find_primary_channel_by_offer(offer);
+
+ if (oldchannel != NULL) {
+ atomic_dec(&vmbus_connection.offer_in_progress);
+
+ /*
+ * We're resuming from hibernation: we expect the host to send
+ * exactly the same offers that we had before the hibernation.
+ */
+ offer_sz = sizeof(*offer);
+ if (memcmp(offer, &oldchannel->offermsg, offer_sz) == 0)
+ return;
+
+ pr_debug("Mismatched offer from the host (relid=%d)\n",
+ offer->child_relid);
+
+ print_hex_dump_debug("Old vmbus offer: ", DUMP_PREFIX_OFFSET,
+ 16, 4, &oldchannel->offermsg, offer_sz,
+ false);
+ print_hex_dump_debug("New vmbus offer: ", DUMP_PREFIX_OFFSET,
+ 16, 4, offer, offer_sz, false);
+ return;
+ }
+
/* Allocate the channel object and save this offer. */
newchannel = alloc_channel();
if (!newchannel) {