From: Tingwei Zhang Date: Mon, 28 Sep 2020 16:35:08 +0000 (-0600) Subject: coresight: cti: Increase reference count when enabling cti X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f02b089e7bddd2f66e63f926960a4e384b1f436d;p=linux.git coresight: cti: Increase reference count when enabling cti 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 Signed-off-by: Tingwei Zhang Signed-off-by: Mathieu Poirier Link: https://lore.kernel.org/r/20200928163513.70169-21-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 711beb92166aa..546c97045afed 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -241,19 +241,30 @@ 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; } }