Re: [PATCH 2/3] cxl: Introduce module parameter 'enable_psltrace'

[christophe lombard]

Le 09/02/2018 à 05:25, Vaibhav Jain a écrit :

We introduce a new module parameter named 'enable_psltrace' which asks cxl
to start(by default) psl-traces on an adapter as soon as its probe is
finished. In case this default behavior is not needed then this
module parameter can be set to '0'.

Signed-off-by: Vaibhav Jain <vaib...@linux.vnet.ibm.com>
---
  drivers/misc/cxl/cxl.h  | 2 ++
  drivers/misc/cxl/main.c | 4 ++++
  drivers/misc/cxl/pci.c  | 3 +++
  3 files changed, 9 insertions(+)

diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index 81da307b60c0..1af66451cbb4 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -28,6 +28,7 @@
  #include <uapi/misc/cxl.h>

  extern uint cxl_verbose;
+extern bool cxl_enable_psltrace;

  #define CXL_TIMEOUT 5

@@ -678,6 +679,7 @@ struct cxl_service_layer_ops {
        void (*psl_irq_dump_registers)(struct cxl_context *ctx);
        void (*err_irq_dump_registers)(struct cxl *adapter);
        void (*stop_psltrace)(struct cxl *adapter);
+       void (*start_psltrace)(struct cxl *adapter);
        void (*write_timebase_ctrl)(struct cxl *adapter);
        u64 (*timebase_read)(struct cxl *adapter);
        int capi_mode;
diff --git a/drivers/misc/cxl/main.c b/drivers/misc/cxl/main.c
index c1ba0d42cbc8..593f2cdba3d8 100644
--- a/drivers/misc/cxl/main.c
+++ b/drivers/misc/cxl/main.c
@@ -34,6 +34,10 @@ uint cxl_verbose;
  module_param_named(verbose, cxl_verbose, uint, 0600);
  MODULE_PARM_DESC(verbose, "Enable verbose dmesg output");

+bool cxl_enable_psltrace = true;
+module_param_named(enable_psltrace, cxl_enable_psltrace, bool, 0600);
+MODULE_PARM_DESC(enable_psltrace, "Set PSL traces on probe. default: on");
+

I am not too agree to add a new parameter. This can cause doubts.
PSL team has confirmed that enabling traces has no impact.
Do you see any reason to disable the traces ?

  const struct cxl_backend_ops *cxl_ops;

  int cxl_afu_slbia(struct cxl_afu *afu)
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index 926b13973b73..9e8b8525534c 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -1726,6 +1726,9 @@ static int cxl_configure_adapter(struct cxl *adapter, 
struct pci_dev *dev)
        if ((rc = cxl_native_register_psl_err_irq(adapter)))
                goto err;

+       if (cxl_enable_psltrace && adapter->native->sl_ops->start_psltrace)
+               adapter->native->sl_ops->start_psltrace(adapter);
+
        return 0;

  err: