misc: fastrpc: handle interrupted contexts

Buffers owned by a context that has been interrupted either by a
signal or a timeout might still be being accessed by the DSP.

delegate returning the associated memory to a later time when the
device is released.
Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20191009144123.24583-5-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/fastrpc.c

@@ -984,12 +984,13 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl,  u32 kernel,
 	}
 
 bail:
-	/* We are done with this compute context, remove it from pending list */
-	spin_lock(&fl->lock);
-	list_del(&ctx->node);
-	spin_unlock(&fl->lock);
-	fastrpc_context_put(ctx);
-
+	if (err != -ERESTARTSYS && err != -ETIMEDOUT) {
+		/* We are done with this compute context */
+		spin_lock(&fl->lock);
+		list_del(&ctx->node);
+		spin_unlock(&fl->lock);
+		fastrpc_context_put(ctx);
+	}
 	if (err)
 		dev_dbg(fl->sctx->dev, "Error: Invoke Failed %d\n", err);