mei: add mei_hbuf_acquire wrapper

A client has to acquire host buffer
before writing, we add lock like wrapper
to replace the code snippet

if (dev->hbuf_is_ready)
        dev->hbuf_is_ready = false;

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

1 files changed, 36 insertions, 20 deletions

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 2df0efab00a2..083179b75297 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -371,6 +371,23 @@ void mei_host_client_init(struct work_struct *work)
         mutex_unlock(&dev->device_lock);
 }
 
+/**
+ * mei_hbuf_acquire: try to acquire host buffer
+ *
+ * @dev: the device structure
+ * returns true if host buffer was acquired
+ */
+bool mei_hbuf_acquire(struct mei_device *dev)
+{
+        if (!dev->hbuf_is_ready) {
+                dev_dbg(&dev->pdev->dev, "hbuf is not ready\n");
+                return false;
+        }
+
+        dev->hbuf_is_ready = false;
+
+        return true;
+}
 
 /**
  * mei_cl_disconnect - disconnect host client from the me one
@@ -402,8 +419,7 @@ int mei_cl_disconnect(struct mei_cl *cl)
                 return -ENOMEM;
 
         cb->fop_type = MEI_FOP_CLOSE;
-        if (dev->hbuf_is_ready) {
-                dev->hbuf_is_ready = false;
+        if (mei_hbuf_acquire(dev)) {
                 if (mei_hbm_cl_disconnect_req(dev, cl)) {
                         rets = -ENODEV;
                         cl_err(dev, cl, "failed to disconnect.\n");
@@ -503,9 +519,8 @@ int mei_cl_connect(struct mei_cl *cl, struct file *file)
 
         cb->fop_type = MEI_FOP_CONNECT;
 
-        if (dev->hbuf_is_ready && !mei_cl_is_other_connecting(cl)) {
-                dev->hbuf_is_ready = false;
-
+        /* run hbuf acquire last so we don't have to undo */
+        if (!mei_cl_is_other_connecting(cl) && mei_hbuf_acquire(dev)) {
                 if (mei_hbm_cl_connect_req(dev, cl)) {
                         rets = -ENODEV;
                         goto out;
@@ -663,8 +678,7 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length)
                 goto err;
 
         cb->fop_type = MEI_FOP_READ;
-        if (dev->hbuf_is_ready) {
-                dev->hbuf_is_ready = false;
+        if (mei_hbuf_acquire(dev)) {
                 if (mei_hbm_cl_flow_control_req(dev, cl)) {
                         cl_err(dev, cl, "flow control send failed\n");
                         rets = -ENODEV;
@@ -799,21 +813,29 @@ int mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, bool blocking)
 
 
         cb->fop_type = MEI_FOP_WRITE;
+        cb->buf_idx = 0;
+        cl->writing_state = MEI_IDLE;
+
+        mei_hdr.host_addr = cl->host_client_id;
+        mei_hdr.me_addr = cl->me_client_id;
+        mei_hdr.reserved = 0;
+        mei_hdr.msg_complete = 0;
+        mei_hdr.internal = cb->internal;
 
         rets = mei_cl_flow_ctrl_creds(cl);
         if (rets < 0)
                 goto err;
 
-        /* Host buffer is not ready, we queue the request */
-        if (rets == 0 || !dev->hbuf_is_ready) {
-                cb->buf_idx = 0;
-                /* unseting complete will enqueue the cb for write */
-                mei_hdr.msg_complete = 0;
+        if (rets == 0) {
+                cl_dbg(dev, cl, "No flow control credentials: not sending.\n");
+                rets = buf->size;
+                goto out;
+        }
+        if (!mei_hbuf_acquire(dev)) {
+                cl_dbg(dev, cl, "Cannot acquire the host buffer: not sending.\n");
                 rets = buf->size;
                 goto out;
         }
-
-        dev->hbuf_is_ready = false;
 
         /* Check for a maximum length */
         if (buf->size > mei_hbuf_max_len(dev)) {
@@ -824,12 +846,6 @@ int mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, bool blocking)
                 mei_hdr.msg_complete = 1;
         }
 
-        mei_hdr.host_addr = cl->host_client_id;
-        mei_hdr.me_addr = cl->me_client_id;
-        mei_hdr.reserved = 0;
-        mei_hdr.internal = cb->internal;
-
-
         rets = mei_write_message(dev, &mei_hdr, buf->data);
         if (rets)
                 goto err;