cxl: Fix device reference leak in cxl_port_perf_data_calculate()

cxl_port_perf_data_calculate() calls find_cxl_root() and does not
dereference the 'struct device' in the cxl_root->port. find_cxl_root()
calls get_device() and takes a reference on the port 'struct device'
member. Use the __free() macro to ensure the dereference happens.

Fixes: 7a4f148dd8d5 ("cxl: Compute the entire CXL path latency and bandwidth data")
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/170449246681.3779673.2288926019977963333.stgit@djiang5-mobl3
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index 0df5379..c6208aa 100644 (file)
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -162,7 +162,6 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
                                        struct xarray *dsmas_xa)
 {
        struct access_coordinate c;
-       struct cxl_root *cxl_root;
        struct dsmas_entry *dent;
        int valid_entries = 0;
        unsigned long index;
@@ -174,7 +173,11 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
                return rc;
        }
 
-       cxl_root = find_cxl_root(port);
+       struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);
+
+       if (!cxl_root)
+               return -ENODEV;
+
        if (!cxl_root->ops || !cxl_root->ops->qos_class)
                return -EOPNOTSUPP;