When coresight device is in an active session, driver module of that device should not be removed. Use try_get_module() in coresight_grab_device() to prevent module to be unloaded. Use get_device()/put_device() to protect device data in the middle of active session.
Signed-off-by: Tingwei Zhang tingwei@codeaurora.org --- drivers/hwtracing/coresight/coresight.c | 39 +++++++++++++++++++++---- 1 file changed, 34 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index b7151c5f81b1..1626bc885dfe 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -640,7 +640,7 @@ struct coresight_device *coresight_get_sink_by_id(u32 id) * don't appear on the trace path, they should be handled along with the * the master device. */ -static void coresight_grab_device(struct coresight_device *csdev) +static int coresight_grab_device(struct coresight_device *csdev) { int i;
@@ -648,10 +648,30 @@ static void coresight_grab_device(struct coresight_device *csdev) struct coresight_device *child;
child = csdev->pdata->conns[i].child_dev; - if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) { + if (!try_module_get(child->dev.parent->driver->owner)) + goto err; + get_device(child->dev.parent); pm_runtime_get_sync(child->dev.parent); + } } + if (!try_module_get(csdev->dev.parent->driver->owner)) + goto err; + get_device(csdev->dev.parent); pm_runtime_get_sync(csdev->dev.parent); + return 0; +err: + for (i--; i >= 0; i--) { + struct coresight_device *child; + + child = csdev->pdata->conns[i].child_dev; + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) { + pm_runtime_put(child->dev.parent); + put_device(child->dev.parent); + module_put(child->dev.parent->driver->owner); + } + } + return -ENODEV; }
/* @@ -663,12 +683,17 @@ static void coresight_drop_device(struct coresight_device *csdev) int i;
pm_runtime_put(csdev->dev.parent); + put_device(csdev->dev.parent); + module_put(csdev->dev.parent->driver->owner); for (i = 0; i < csdev->pdata->nr_outport; i++) { struct coresight_device *child;
child = csdev->pdata->conns[i].child_dev; - if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) + if (child && child->type == CORESIGHT_DEV_TYPE_HELPER) { pm_runtime_put(child->dev.parent); + put_device(child->dev.parent); + module_put(child->dev.parent->driver->owner); + } } }
@@ -687,7 +712,7 @@ static int _coresight_build_path(struct coresight_device *csdev, struct coresight_device *sink, struct list_head *path) { - int i; + int i, ret; bool found = false; struct coresight_node *node;
@@ -721,7 +746,11 @@ static int _coresight_build_path(struct coresight_device *csdev, if (!node) return -ENOMEM;
- coresight_grab_device(csdev); + ret = coresight_grab_device(csdev); + if (ret) { + kfree(node); + return ret; + } node->csdev = csdev; list_add(&node->link, path);