CTI device is enabled when associated coresight device is enabled. Increase the module and device reference count for CTI device when it's enabled. This can prevent CTI device be removed or module be unloaded when CTI device is enabled by an active trace session.
Signed-off-by: Mike Leach mike.leach@linaro.org Signed-off-by: Tingwei Zhang tingwei@codeaurora.org --- drivers/hwtracing/coresight/coresight.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index b35f5b270a94..78439b7cd8ba 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -242,19 +242,30 @@ coresight_control_assoc_ectdev(struct coresight_device *csdev, bool enable) { int ect_ret = 0; struct coresight_device *ect_csdev = csdev->ect_dev; + struct module *mod;
if (!ect_csdev) return 0; if ((!ect_ops(ect_csdev)->enable) || (!ect_ops(ect_csdev)->disable)) return 0;
+ mod = ect_csdev->dev.parent->driver->owner; if (enable) { - ect_ret = ect_ops(ect_csdev)->enable(ect_csdev); - if (!ect_ret) - csdev->ect_enabled = true; + if (try_module_get(mod)) { + ect_ret = ect_ops(ect_csdev)->enable(ect_csdev); + if (ect_ret) { + module_put(mod); + } else { + get_device(ect_csdev->dev.parent); + csdev->ect_enabled = true; + } + } else + ect_ret = -ENODEV; } else { if (csdev->ect_enabled) { ect_ret = ect_ops(ect_csdev)->disable(ect_csdev); + put_device(ect_csdev->dev.parent); + module_put(mod); csdev->ect_enabled = false; } }