[PATCH -next] gpu: host1x: fix memory leak of device names

[Yang Yingliang]

The device names allocated by dev_set_name() need be freed
before module unloading, but they can not be freed because
the kobject's refcount which was set in device_initialize()
has not be decreased to 0.

Fix the name leak by calling put_device() to give up the refcount,
so the name can be freed in kobejct_cleanup().

Add a release() function to device, it's empty, because the
context devices are freed together in host1x_memory_context_list_free().

Fixes: 8aa5bcb61612 ("gpu: host1x: Add context device management code")
Signed-off-by: Yang Yingliang <yangyingliang at huawei.com>
---
 drivers/gpu/host1x/context.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/host1x/context.c b/drivers/gpu/host1x/context.c
index b08cf11f9a66..f49a7bf6afa5 100644
--- a/drivers/gpu/host1x/context.c
+++ b/drivers/gpu/host1x/context.c
@@ -13,6 +13,11 @@
 #include "context.h"
 #include "dev.h"
 
+static void host1x_memory_context_release(struct device *dev)
+{
+	/* context device is freed in host1x_memory_context_list_free() */
+}
+
 int host1x_memory_context_list_init(struct host1x *host1x)
 {
 	struct host1x_memory_context_list *cdl = &host1x->context_list;
@@ -53,28 +58,27 @@ int host1x_memory_context_list_init(struct host1x *host1x)
 		dev_set_name(&ctx->dev, "host1x-ctx.%d", i);
 		ctx->dev.bus = &host1x_context_device_bus_type;
 		ctx->dev.parent = host1x->dev;
+		ctx->dev.release = host1x_memory_context_release;
 
 		dma_set_max_seg_size(&ctx->dev, UINT_MAX);
 
 		err = device_add(&ctx->dev);
 		if (err) {
 			dev_err(host1x->dev, "could not add context device %d: %d\n", i, err);
-			goto del_devices;
+			goto put_dev;
 		}
 
 		err = of_dma_configure_id(&ctx->dev, node, true, &i);
 		if (err) {
 			dev_err(host1x->dev, "IOMMU configuration failed for context device %d: %d\n",
 				i, err);
-			device_del(&ctx->dev);
-			goto del_devices;
+			goto unreg_devices;
 		}
 
 		fwspec = dev_iommu_fwspec_get(&ctx->dev);
 		if (!fwspec || !device_iommu_mapped(&ctx->dev)) {
 			dev_err(host1x->dev, "Context device %d has no IOMMU!\n", i);
-			device_del(&ctx->dev);
-			goto del_devices;
+			goto unreg_devices;
 		}
 
 		ctx->stream_id = fwspec->ids[0] & 0xffff;
@@ -82,9 +86,12 @@ int host1x_memory_context_list_init(struct host1x *host1x)
 
 	return 0;
 
-del_devices:
-	while (i--)
-		device_del(&cdl->devs[i].dev);
+put_dev:
+	put_device(&cdl->devs[i--].dev);
+
+unreg_devices:
+	while (i >= 0)
+		device_unregister(&cdl->devs[i--].dev);
 
 	kfree(cdl->devs);
 	cdl->len = 0;
@@ -97,7 +104,7 @@ void host1x_memory_context_list_free(struct host1x_memory_context_list *cdl)
 	unsigned int i;
 
 	for (i = 0; i < cdl->len; i++)
-		device_del(&cdl->devs[i].dev);
+		device_unregister(&cdl->devs[i].dev);
 
 	kfree(cdl->devs);
 	cdl->len = 0;
-- 
2.25.1