mei: add read callback on demand for fixed_address clients

The Fixed address clients do not work with the flow control, and the
packet RX callback was allocated upon TX with anticipation of a
following RX. This won't work if the clients with unsolicited Rx. Rather
than preparing read callback upon a write we allocate one directly on
the reciev path if one doesn't exists.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index 8b5e4b4c4c15..44ba90140725 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -107,8 +107,14 @@ int mei_cl_irq_read_msg(struct mei_cl *cl,
 
         cb = list_first_entry_or_null(&cl->rd_pending, struct mei_cl_cb, list);
         if (!cb) {
-                cl_err(dev, cl, "pending read cb not found\n");
-                goto out;
+                if (!mei_cl_is_fixed_address(cl)) {
+                        cl_err(dev, cl, "pending read cb not found\n");
+                        goto out;
+                }
+                cb = mei_cl_alloc_cb(cl, mei_cl_mtu(cl), MEI_FOP_READ, cl->fp);
+                if (!cb)
+                        goto out;
+                list_add_tail(&cb->list, &cl->rd_pending);
         }
 
         if (!mei_cl_is_connected(cl)) {