[PATCH v3 19/20] coresight: add try_get_module() in coresight_grab_device()
From: Tingwei Zhang <hidden>
Date: 2020-07-17 05:52:18
Subsystem:
arm/coresight framework and drivers, hardware tracing facilities, the rest · Maintainers:
Suzuki K Poulose, Alexander Shishkin, Linus Torvalds
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. Signed-off-by: Tingwei Zhang <redacted> --- drivers/hwtracing/coresight/coresight.c | 27 +++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 55b699aca9ec..eabb59531c75 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c@@ -655,7 +655,7 @@ 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;
@@ -663,10 +663,25 @@ 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; pm_runtime_get_sync(child->dev.parent); + } } + if (!try_module_get(csdev->dev.parent->driver->owner)) + goto err; 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); + } + return -ENODEV; } /*
@@ -678,12 +693,15 @@ static void coresight_drop_device(struct coresight_device *csdev) int i; pm_runtime_put(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); + module_put(child->dev.parent->driver->owner); + } } }
@@ -736,7 +754,8 @@ static int _coresight_build_path(struct coresight_device *csdev, if (!node) return -ENOMEM; - coresight_grab_device(csdev); + if (coresight_grab_device(csdev)) + return -ENODEV; node->csdev = csdev; list_add(&node->link, path);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel