Re: [PATCH v6 21/25] coresight: cti: increase reference count when enabling cti

Please see my comment from the previous patch regarding the function here.

Mike

On Fri, 31 Jul 2020 at 07:42, Tingwei Zhang tingwei@codeaurora.org wrote:

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 83a46cf37968..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;
            }
    }
  

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-- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK