Drivers: hv: util: Pass the channel information during the init call

Pass the channel information to the util drivers that need to defer
reading the channel while they are processing a request. This would address
the following issue reported by Vitaly:

Commit 3cace4a61610 ("Drivers: hv: utils: run polling callback always in
interrupt context") removed direct *_transaction.state = HVUTIL_READY
assignments from *_handle_handshake() functions introducing the following
race: if a userspace daemon connects before we get first non-negotiation
request from the server hv_poll_channel() won't set transaction state to
HVUTIL_READY as (!channel) condition will fail, we set it to non-NULL on
the first real request from the server.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index d23dab0d770b..aa0fadce9308 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1251,6 +1251,7 @@ u64 hv_do_hypercall(u64 control, void *input, void *output);
 
 struct hv_util_service {
         u8 *recv_buffer;
+        void *channel;
         void (*util_cb)(void *);
         int (*util_init)(struct hv_util_service *);
         void (*util_deinit)(void);