[v5,3/5] cxl: Fix device reference leak in cxl_port_perf_data_calculate()

Commit Message

Dave Jiang Jan. 5, 2024, 6:03 p.m. UTC

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")
Signed-off-by: Dave Jiang <[e-mail]>
---
v5:
- Update patch title (Dan)
---
 drivers/cxl/core/cdat.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index 0df5379cf02f..c6208aab452f 100644
--- 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;