staging: hv: convert vmbus_on_msg_dpc to not call osd_schedule_callback

The additional abstraction is unneeded. This also fixes a sleeping
while atomic issue as osd_schedule_callback can sleep which is
not allowed for vmbus_on_msg_dpc running in a tasklet.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16701

Reviewed-By: Hank Janssen <hjanssen@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 21 insertions, 11 deletions

diff --git a/drivers/staging/hv/channel_mgmt.c b/drivers/staging/hv/channel_mgmt.c
index 0f4d6093f674..6f393e7d8e25 100644
--- a/drivers/staging/hv/channel_mgmt.c
+++ b/drivers/staging/hv/channel_mgmt.c
@@ -753,7 +753,6 @@ void vmbus_onmessage(void *context)
                            hdr->msgtype, size);
                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
                                      (unsigned char *)msg->u.payload, size);
-                kfree(msg);
                 return;
         }
 
@@ -762,9 +761,6 @@ void vmbus_onmessage(void *context)
         else
                 DPRINT_ERR(VMBUS, "Unhandled channel message type %d",
                            hdr->msgtype);
-
-        /* Free the msg that was allocated in VmbusOnMsgDPC() */
-        kfree(msg);
 }
 
 /*
diff --git a/drivers/staging/hv/vmbus_drv.c b/drivers/staging/hv/vmbus_drv.c
index d794b603bf17..84fdb64d3ceb 100644
--- a/drivers/staging/hv/vmbus_drv.c
+++ b/drivers/staging/hv/vmbus_drv.c
@@ -203,6 +203,21 @@ static void VmbusOnCleanup(struct hv_driver *drv)
         hv_cleanup();
 }
 
+struct onmessage_work_context {
+        struct work_struct work;
+        struct hv_message msg;
+};
+
+static void vmbus_onmessage_work(struct work_struct *work)
+{
+        struct onmessage_work_context *ctx;
+
+        ctx = container_of(work, struct onmessage_work_context,
+                           work);
+        vmbus_onmessage(&ctx->msg);
+        kfree(ctx);
+}
+
 /*
  * vmbus_on_msg_dpc - DPC routine to handle messages from the hypervisior
  */
@@ -212,20 +227,19 @@ static void vmbus_on_msg_dpc(struct hv_driver *drv)
         void *page_addr = hv_context.synic_message_page[cpu];
         struct hv_message *msg = (struct hv_message *)page_addr +
                                   VMBUS_MESSAGE_SINT;
-        struct hv_message *copied;
+        struct onmessage_work_context *ctx;
 
         while (1) {
                 if (msg->header.message_type == HVMSG_NONE) {
                         /* no msg */
                         break;
                 } else {
-                        copied = kmemdup(msg, sizeof(*copied), GFP_ATOMIC);
-                        if (copied == NULL)
+                        ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
+                        if (ctx == NULL)
                                 continue;
-
-                        osd_schedule_callback(gVmbusConnection.WorkQueue,
-                                              vmbus_onmessage,
-                                              (void *)copied);
+                        INIT_WORK(&ctx->work, vmbus_onmessage_work);
+                        memcpy(&ctx->msg, msg, sizeof(*msg));
+                        queue_work(gVmbusConnection.WorkQueue, &ctx->work);
                 }
 
                 msg->header.message_type = HVMSG_NONE;