[PATCH 05/15] dmaengine: idxd: fix device leaks on compat bind and unbind

[Johan Hovold <johan@kernel.org>]

Make sure to drop the reference taken when looking up the idxd device as
part of the compat bind and unbind sysfs interface.

Fixes: 6e7f3ee97bbe ("dmaengine: idxd: move dsa_drv support to compatible mode")
Cc: stable@vger.kernel.org	# 5.15
Cc: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/dma/idxd/compat.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/idxd/compat.c b/drivers/dma/idxd/compat.c
index eff9943f1a42..95b8ef958633 100644
--- a/drivers/dma/idxd/compat.c
+++ b/drivers/dma/idxd/compat.c
@@ -20,11 +20,16 @@ static ssize_t unbind_store(struct device_driver *drv, const char *buf, size_t c
 	int rc = -ENODEV;
 
 	dev = bus_find_device_by_name(bus, NULL, buf);
-	if (dev && dev->driver) {
+	if (!dev)
+		return -ENODEV;
+
+	if (dev->driver) {
 		device_driver_detach(dev);
 		rc = count;
 	}
 
+	put_device(dev);
+
 	return rc;
 }
 static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, 0200, NULL, unbind_store);
@@ -38,9 +43,12 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, size_t cou
 	struct idxd_dev *idxd_dev;
 
 	dev = bus_find_device_by_name(bus, NULL, buf);
-	if (!dev || dev->driver || drv != &dsa_drv.drv)
+	if (!dev)
 		return -ENODEV;
 
+	if (dev->driver || drv != &dsa_drv.drv)
+		goto err_put_dev;
+
 	idxd_dev = confdev_to_idxd_dev(dev);
 	if (is_idxd_dev(idxd_dev)) {
 		alt_drv = driver_find("idxd", bus);
@@ -53,13 +61,20 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, size_t cou
 			alt_drv = driver_find("user", bus);
 	}
 	if (!alt_drv)
-		return -ENODEV;
+		goto err_put_dev;
 
 	rc = device_driver_attach(alt_drv, dev);
 	if (rc < 0)
-		return rc;
+		goto err_put_dev;
+
+	put_device(dev);
 
 	return count;
+
+err_put_dev:
+	put_device(dev);
+
+	return rc;
 }
 static DRIVER_ATTR_IGNORE_LOCKDEP(bind, 0200, NULL, bind_store);
 
-- 
2.51.0