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[PATCH v5] PCI: hotplug: Add a generic RAS tracepoint for hotplug event

Shuai Xue posted 1 patch 11 months, 2 weeks ago
There is a newer version of this series
drivers/pci/hotplug/pciehp_ctrl.c | 33 ++++++++++++---
drivers/pci/hotplug/trace.h       | 68 +++++++++++++++++++++++++++++++
include/uapi/linux/pci.h          |  7 ++++
3 files changed, 102 insertions(+), 6 deletions(-)
create mode 100644 drivers/pci/hotplug/trace.h
[PATCH v5] PCI: hotplug: Add a generic RAS tracepoint for hotplug event
Posted by Shuai Xue 11 months, 2 weeks ago 
Hotplug events are critical indicators for analyzing hardware health,
particularly in AI supercomputers where surprise link downs can
significantly impact system performance and reliability.

To this end, define a new TRACING_SYSTEM named pci, add a generic RAS
tracepoint for hotplug event to help healthy check, and generate
tracepoints for pcie hotplug event. Add enum pci_hotplug_event in
include/uapi/linux/pci.h so applications like rasdaemon can register
tracepoint event handlers for it.

The output like below:

$ echo 1 > /sys/kernel/debug/tracing/events/pci/pci_hp_event/enable
$ cat /sys/kernel/debug/tracing/trace_pipe
    <...>-206     [001] .....    40.373870: pci_hp_event: 0000:00:02.0 slot:10, event:Link Down

    <...>-206     [001] .....    40.374871: pci_hp_event: 0000:00:02.0 slot:10, event:Card not present

Suggested-by: Lukas Wunner <lukas@wunner.de>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
---
change log since v4:
- rebase to pci/main (v6.13-rc1) (per Bjorn)
- rewrite commit log with generic motivation (per Bjorn)
---
 drivers/pci/hotplug/pciehp_ctrl.c | 33 ++++++++++++---
 drivers/pci/hotplug/trace.h       | 68 +++++++++++++++++++++++++++++++
 include/uapi/linux/pci.h          |  7 ++++
 3 files changed, 102 insertions(+), 6 deletions(-)
 create mode 100644 drivers/pci/hotplug/trace.h

diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index d603a7aa7483..f9beb4d3a9b8 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -23,6 +23,9 @@
 #include "../pci.h"
 #include "pciehp.h"
 
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
 /* The following routines constitute the bulk of the
    hotplug controller logic
  */
@@ -244,12 +247,20 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 	case ON_STATE:
 		ctrl->state = POWEROFF_STATE;
 		mutex_unlock(&ctrl->state_lock);
-		if (events & PCI_EXP_SLTSTA_DLLSC)
+		if (events & PCI_EXP_SLTSTA_DLLSC) {
 			ctrl_info(ctrl, "Slot(%s): Link Down\n",
 				  slot_name(ctrl));
-		if (events & PCI_EXP_SLTSTA_PDC)
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_LINK_DOWN);
+		}
+		if (events & PCI_EXP_SLTSTA_PDC) {
 			ctrl_info(ctrl, "Slot(%s): Card not present\n",
 				  slot_name(ctrl));
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_CARD_NOT_PRESENT);
+		}
 		pciehp_disable_slot(ctrl, SURPRISE_REMOVAL);
 		break;
 	default:
@@ -269,6 +280,9 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 					      INDICATOR_NOOP);
 			ctrl_info(ctrl, "Slot(%s): Card not present\n",
 				  slot_name(ctrl));
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_CARD_NOT_PRESENT);
 		}
 		mutex_unlock(&ctrl->state_lock);
 		return;
@@ -281,12 +295,19 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 	case OFF_STATE:
 		ctrl->state = POWERON_STATE;
 		mutex_unlock(&ctrl->state_lock);
-		if (present)
+		if (present) {
 			ctrl_info(ctrl, "Slot(%s): Card present\n",
 				  slot_name(ctrl));
-		if (link_active)
-			ctrl_info(ctrl, "Slot(%s): Link Up\n",
-				  slot_name(ctrl));
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_CARD_PRESENT);
+		}
+		if (link_active) {
+			ctrl_info(ctrl, "Slot(%s): Link Up\n", slot_name(ctrl));
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_LINK_UP);
+		}
 		ctrl->request_result = pciehp_enable_slot(ctrl);
 		break;
 	default:
diff --git a/drivers/pci/hotplug/trace.h b/drivers/pci/hotplug/trace.h
new file mode 100644
index 000000000000..5b60cd7bcffb
--- /dev/null
+++ b/drivers/pci/hotplug/trace.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#if !defined(_TRACE_HW_EVENT_PCI_HP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HW_EVENT_PCI_HP_H
+
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM pci
+
+#define PCI_HOTPLUG_EVENT					\
+	EM(PCI_HOTPLUG_LINK_UP,			"Link Up")	\
+	EM(PCI_HOTPLUG_LINK_DOWN,		"Link Down")	\
+	EM(PCI_HOTPLUG_CARD_PRESENT,		"Card present")	\
+	EMe(PCI_HOTPLUG_CARD_NOT_PRESENT,	"Card not present")
+
+/* Enums require being exported to userspace, for user tool parsing */
+#undef EM
+#undef EMe
+#define EM(a, b)	TRACE_DEFINE_ENUM(a);
+#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
+
+PCI_HOTPLUG_EVENT
+
+/*
+ * Now redefine the EM() and EMe() macros to map the enums to the strings
+ * that will be printed in the output.
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)	{a, b},
+#define EMe(a, b)	{a, b}
+
+TRACE_EVENT(pci_hp_event,
+
+	TP_PROTO(const char *port_name,
+		 const char *slot,
+		 const int event),
+
+	TP_ARGS(port_name, slot, event),
+
+	TP_STRUCT__entry(
+		__string(	port_name,	port_name	)
+		__string(	slot,		slot		)
+		__field(	int,		event	)
+	),
+
+	TP_fast_assign(
+		__assign_str(port_name);
+		__assign_str(slot);
+		__entry->event = event;
+	),
+
+	TP_printk("%s slot:%s, event:%s\n",
+		__get_str(port_name),
+		__get_str(slot),
+		__print_symbolic(__entry->event, PCI_HOTPLUG_EVENT)
+	)
+);
+
+#endif /* _TRACE_HW_EVENT_PCI_HP_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH  ../../drivers/pci/hotplug
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/include/uapi/linux/pci.h b/include/uapi/linux/pci.h
index a769eefc5139..4f150028965d 100644
--- a/include/uapi/linux/pci.h
+++ b/include/uapi/linux/pci.h
@@ -39,4 +39,11 @@
 #define PCIIOC_MMAP_IS_MEM	(PCIIOC_BASE | 0x02)	/* Set mmap state to MEM space. */
 #define PCIIOC_WRITE_COMBINE	(PCIIOC_BASE | 0x03)	/* Enable/disable write-combining. */
 
+enum pci_hotplug_event {
+	PCI_HOTPLUG_LINK_UP,
+	PCI_HOTPLUG_LINK_DOWN,
+	PCI_HOTPLUG_CARD_PRESENT,
+	PCI_HOTPLUG_CARD_NOT_PRESENT,
+};
+
 #endif /* _UAPILINUX_PCI_H */
-- 
2.39.3
Re: [PATCH v5] PCI: hotplug: Add a generic RAS tracepoint for hotplug event
Posted by Steven Rostedt 11 months, 1 week ago 
On Thu,  9 Jan 2025 10:55:43 +0800
Shuai Xue <xueshuai@linux.alibaba.com> wrote:

> diff --git a/drivers/pci/hotplug/trace.h b/drivers/pci/hotplug/trace.h
> new file mode 100644
> index 000000000000..5b60cd7bcffb
> --- /dev/null
> +++ b/drivers/pci/hotplug/trace.h
> @@ -0,0 +1,68 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#if !defined(_TRACE_HW_EVENT_PCI_HP_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_HW_EVENT_PCI_HP_H
> +
> +#include <linux/tracepoint.h>
> +
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM pci
> +
> +#define PCI_HOTPLUG_EVENT					\
> +	EM(PCI_HOTPLUG_LINK_UP,			"Link Up")	\
> +	EM(PCI_HOTPLUG_LINK_DOWN,		"Link Down")	\
> +	EM(PCI_HOTPLUG_CARD_PRESENT,		"Card present")	\
> +	EMe(PCI_HOTPLUG_CARD_NOT_PRESENT,	"Card not present")

Since you are creating these enums in this patch, you can also do a
shortcut here too. Instead of doing the define here, move it to
include/uapi/linux/pci.h:

> +
> +/* Enums require being exported to userspace, for user tool parsing */
> +#undef EM
> +#undef EMe
> +#define EM(a, b)	TRACE_DEFINE_ENUM(a);
> +#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
> +
> +PCI_HOTPLUG_EVENT
> +
> +/*
> + * Now redefine the EM() and EMe() macros to map the enums to the strings
> + * that will be printed in the output.
> + */
> +#undef EM
> +#undef EMe
> +#define EM(a, b)	{a, b},
> +#define EMe(a, b)	{a, b}
> +
> +TRACE_EVENT(pci_hp_event,
> +
> +	TP_PROTO(const char *port_name,
> +		 const char *slot,
> +		 const int event),
> +
> +	TP_ARGS(port_name, slot, event),
> +
> +	TP_STRUCT__entry(
> +		__string(	port_name,	port_name	)
> +		__string(	slot,		slot		)
> +		__field(	int,		event	)
> +	),
> +
> +	TP_fast_assign(
> +		__assign_str(port_name);
> +		__assign_str(slot);
> +		__entry->event = event;
> +	),
> +
> +	TP_printk("%s slot:%s, event:%s\n",
> +		__get_str(port_name),
> +		__get_str(slot),
> +		__print_symbolic(__entry->event, PCI_HOTPLUG_EVENT)
> +	)
> +);
> +
> +#endif /* _TRACE_HW_EVENT_PCI_HP_H */
> +
> +#undef TRACE_INCLUDE_PATH
> +#define TRACE_INCLUDE_PATH  ../../drivers/pci/hotplug
> +#undef TRACE_INCLUDE_FILE
> +#define TRACE_INCLUDE_FILE trace
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
> diff --git a/include/uapi/linux/pci.h b/include/uapi/linux/pci.h
> index a769eefc5139..4f150028965d 100644
> --- a/include/uapi/linux/pci.h
> +++ b/include/uapi/linux/pci.h
> @@ -39,4 +39,11 @@
>  #define PCIIOC_MMAP_IS_MEM	(PCIIOC_BASE | 0x02)	/* Set mmap state to MEM space. */
>  #define PCIIOC_WRITE_COMBINE	(PCIIOC_BASE | 0x03)	/* Enable/disable write-combining. */
>  
> +enum pci_hotplug_event {
> +	PCI_HOTPLUG_LINK_UP,
> +	PCI_HOTPLUG_LINK_DOWN,
> +	PCI_HOTPLUG_CARD_PRESENT,
> +	PCI_HOTPLUG_CARD_NOT_PRESENT,
> +};

Instead of defining the enum as you did above, if you have the define of
the enums here, you could do:

#define PCI_HOTPLUG_EVENT					\
	EM(PCI_HOTPLUG_LINK_UP,			"Link Up")	\
	EM(PCI_HOTPLUG_LINK_DOWN,		"Link Down")	\
	EM(PCI_HOTPLUG_CARD_PRESENT,		"Card present")	\
	EMe(PCI_HOTPLUG_CARD_NOT_PRESENT,	"Card not present")

#undef EM
#undef EMe
#define EM(a, b)	a,
#define EMe(a, b)	a,

enum pci_hotplug_event {
	PCI_HOTPLUG_EVENT
};

Then you only have one place to worry about adding new enums ;-)

-- Steve

> +
>  #endif /* _UAPILINUX_PCI_H */
Re: [PATCH v5] PCI: hotplug: Add a generic RAS tracepoint for hotplug event
Posted by Shuai Xue 9 months, 2 weeks ago 

在 2025/1/14 04:55, Steven Rostedt 写道:
> On Thu,  9 Jan 2025 10:55:43 +0800
> Shuai Xue <xueshuai@linux.alibaba.com> wrote:
> 
>> diff --git a/drivers/pci/hotplug/trace.h b/drivers/pci/hotplug/trace.h
>> new file mode 100644
>> index 000000000000..5b60cd7bcffb
>> --- /dev/null
>> +++ b/drivers/pci/hotplug/trace.h
>> @@ -0,0 +1,68 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +#if !defined(_TRACE_HW_EVENT_PCI_HP_H) || defined(TRACE_HEADER_MULTI_READ)
>> +#define _TRACE_HW_EVENT_PCI_HP_H
>> +
>> +#include <linux/tracepoint.h>
>> +
>> +#undef TRACE_SYSTEM
>> +#define TRACE_SYSTEM pci
>> +
>> +#define PCI_HOTPLUG_EVENT					\
>> +	EM(PCI_HOTPLUG_LINK_UP,			"Link Up")	\
>> +	EM(PCI_HOTPLUG_LINK_DOWN,		"Link Down")	\
>> +	EM(PCI_HOTPLUG_CARD_PRESENT,		"Card present")	\
>> +	EMe(PCI_HOTPLUG_CARD_NOT_PRESENT,	"Card not present")
> 
> Since you are creating these enums in this patch, you can also do a
> shortcut here too. Instead of doing the define here, move it to
> include/uapi/linux/pci.h:
> 
>> +
>> +/* Enums require being exported to userspace, for user tool parsing */
>> +#undef EM
>> +#undef EMe
>> +#define EM(a, b)	TRACE_DEFINE_ENUM(a);
>> +#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
>> +
>> +PCI_HOTPLUG_EVENT
>> +
>> +/*
>> + * Now redefine the EM() and EMe() macros to map the enums to the strings
>> + * that will be printed in the output.
>> + */
>> +#undef EM
>> +#undef EMe
>> +#define EM(a, b)	{a, b},
>> +#define EMe(a, b)	{a, b}
>> +
>> +TRACE_EVENT(pci_hp_event,
>> +
>> +	TP_PROTO(const char *port_name,
>> +		 const char *slot,
>> +		 const int event),
>> +
>> +	TP_ARGS(port_name, slot, event),
>> +
>> +	TP_STRUCT__entry(
>> +		__string(	port_name,	port_name	)
>> +		__string(	slot,		slot		)
>> +		__field(	int,		event	)
>> +	),
>> +
>> +	TP_fast_assign(
>> +		__assign_str(port_name);
>> +		__assign_str(slot);
>> +		__entry->event = event;
>> +	),
>> +
>> +	TP_printk("%s slot:%s, event:%s\n",
>> +		__get_str(port_name),
>> +		__get_str(slot),
>> +		__print_symbolic(__entry->event, PCI_HOTPLUG_EVENT)
>> +	)
>> +);
>> +
>> +#endif /* _TRACE_HW_EVENT_PCI_HP_H */
>> +
>> +#undef TRACE_INCLUDE_PATH
>> +#define TRACE_INCLUDE_PATH  ../../drivers/pci/hotplug
>> +#undef TRACE_INCLUDE_FILE
>> +#define TRACE_INCLUDE_FILE trace
>> +
>> +/* This part must be outside protection */
>> +#include <trace/define_trace.h>
>> diff --git a/include/uapi/linux/pci.h b/include/uapi/linux/pci.h
>> index a769eefc5139..4f150028965d 100644
>> --- a/include/uapi/linux/pci.h
>> +++ b/include/uapi/linux/pci.h
>> @@ -39,4 +39,11 @@
>>   #define PCIIOC_MMAP_IS_MEM	(PCIIOC_BASE | 0x02)	/* Set mmap state to MEM space. */
>>   #define PCIIOC_WRITE_COMBINE	(PCIIOC_BASE | 0x03)	/* Enable/disable write-combining. */
>>   
>> +enum pci_hotplug_event {
>> +	PCI_HOTPLUG_LINK_UP,
>> +	PCI_HOTPLUG_LINK_DOWN,
>> +	PCI_HOTPLUG_CARD_PRESENT,
>> +	PCI_HOTPLUG_CARD_NOT_PRESENT,
>> +};
> 
> Instead of defining the enum as you did above, if you have the define of
> the enums here, you could do:
> 
> #define PCI_HOTPLUG_EVENT					\
> 	EM(PCI_HOTPLUG_LINK_UP,			"Link Up")	\
> 	EM(PCI_HOTPLUG_LINK_DOWN,		"Link Down")	\
> 	EM(PCI_HOTPLUG_CARD_PRESENT,		"Card present")	\
> 	EMe(PCI_HOTPLUG_CARD_NOT_PRESENT,	"Card not present")
> 
> #undef EM
> #undef EMe
> #define EM(a, b)	a,
> #define EMe(a, b)	a,
> 
> enum pci_hotplug_event {
> 	PCI_HOTPLUG_EVENT
> };
> 
> Then you only have one place to worry about adding new enums ;-)

Hi, Steve,

If I move PCI_HOTPLUG_EVENT into one place, `include/upai/linux/pci.h`,
I need to include:

     #include <linux/tracepoint.h>

Then, kernel build fails with CONFIG_UAPI_HEADER_TEST=y:

$ make -j128
   DESCEND objtool
   CALL    scripts/checksyscalls.sh
   INSTALL libsubcmd_headers
   HDRTEST usr/include/linux/pci.h
In file included from <command-line>:32:
./usr/include/linux/pci.h:22:10: fatal error: linux/tracepoint.h: No such file or directory
    22 | #include <linux/tracepoint.h>
       |          ^~~~~~~~~~~~~~~~~~~~
compilation terminated.
make[4]: *** [usr/include/Makefile:85: usr/include/linux/pci.hdrtest] Error 1
make[3]: *** [scripts/Makefile.build:465: usr/include] Error 2
make[2]: *** [scripts/Makefile.build:465: usr] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [/media/nvme/shawn.xs/kernels/linux/Makefile:1994: .] Error 2
make: *** [Makefile:251: __sub-make] Error 2

Do you have any objections that I reverted to this version v5?

Thanks.
Shuai
Re: [PATCH v5] PCI: hotplug: Add a generic RAS tracepoint for hotplug event
Posted by Steven Rostedt 9 months, 2 weeks ago 
On Mon, 10 Mar 2025 11:59:55 +0800
Shuai Xue <xueshuai@linux.alibaba.com> wrote:

> Hi, Steve,
> 
> If I move PCI_HOTPLUG_EVENT into one place, `include/upai/linux/pci.h`,
> I need to include:
> 
>      #include <linux/tracepoint.h>
> 
> Then, kernel build fails with CONFIG_UAPI_HEADER_TEST=y:

Just move the enum definitions, not the entire event file.

That is, have one place has the PCI_HOTPLUG_EVENT macro, and have both the
uapi header as well as the tracepoint header include that header.

I guess I need to see the entire change.

-- Steve
Re: [PATCH v5] PCI: hotplug: Add a generic RAS tracepoint for hotplug event
Posted by Shuai Xue 9 months, 1 week ago 

在 2025/3/10 22:50, Steven Rostedt 写道:
> On Mon, 10 Mar 2025 11:59:55 +0800
> Shuai Xue <xueshuai@linux.alibaba.com> wrote:
> 
>> Hi, Steve,
>>
>> If I move PCI_HOTPLUG_EVENT into one place, `include/upai/linux/pci.h`,
>> I need to include:
>>
>>       #include <linux/tracepoint.h>
>>
>> Then, kernel build fails with CONFIG_UAPI_HEADER_TEST=y:
> 
> Just move the enum definitions, not the entire event file.
> 
> That is, have one place has the PCI_HOTPLUG_EVENT macro, and have both the
> uapi header as well as the tracepoint header include that header.
> 
> I guess I need to see the entire change.
> 

Hi, Steven,

IMHO, the problem is that the PCI_HOTPLUG_EVENT macro needs to include
"linux/tracepoint.h" but it is not allowed in userspace.

The entire change in v6 build fails with CONFIG_UAPI_HEADER_TEST=y:

   https://lore.kernel.org/lkml/202501190108.tRReJA1Z-lkp@intel.com/T/#mae507b91b8b80c386dfa9e63fbbdd45826c2e003

(sorry, I did not see the problem because my local .config do not set
CONFIG_UAPI_HEADER_TEST)

Thanks
Shuai
Re: [PATCH v5] PCI: hotplug: Add a generic RAS tracepoint for hotplug event
Posted by Shuai Xue 11 months, 1 week ago 

在 2025/1/14 04:55, Steven Rostedt 写道:
> On Thu,  9 Jan 2025 10:55:43 +0800
> Shuai Xue <xueshuai@linux.alibaba.com> wrote:
> 
>> diff --git a/drivers/pci/hotplug/trace.h b/drivers/pci/hotplug/trace.h
>> new file mode 100644
>> index 000000000000..5b60cd7bcffb
>> --- /dev/null
>> +++ b/drivers/pci/hotplug/trace.h
>> @@ -0,0 +1,68 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +#if !defined(_TRACE_HW_EVENT_PCI_HP_H) || defined(TRACE_HEADER_MULTI_READ)
>> +#define _TRACE_HW_EVENT_PCI_HP_H
>> +
>> +#include <linux/tracepoint.h>
>> +
>> +#undef TRACE_SYSTEM
>> +#define TRACE_SYSTEM pci
>> +
>> +#define PCI_HOTPLUG_EVENT					\
>> +	EM(PCI_HOTPLUG_LINK_UP,			"Link Up")	\
>> +	EM(PCI_HOTPLUG_LINK_DOWN,		"Link Down")	\
>> +	EM(PCI_HOTPLUG_CARD_PRESENT,		"Card present")	\
>> +	EMe(PCI_HOTPLUG_CARD_NOT_PRESENT,	"Card not present")
> 
> Since you are creating these enums in this patch, you can also do a
> shortcut here too. Instead of doing the define here, move it to
> include/uapi/linux/pci.h:
> 
>> +
>> +/* Enums require being exported to userspace, for user tool parsing */
>> +#undef EM
>> +#undef EMe
>> +#define EM(a, b)	TRACE_DEFINE_ENUM(a);
>> +#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
>> +
>> +PCI_HOTPLUG_EVENT
>> +
>> +/*
>> + * Now redefine the EM() and EMe() macros to map the enums to the strings
>> + * that will be printed in the output.
>> + */
>> +#undef EM
>> +#undef EMe
>> +#define EM(a, b)	{a, b},
>> +#define EMe(a, b)	{a, b}
>> +
>> +TRACE_EVENT(pci_hp_event,
>> +
>> +	TP_PROTO(const char *port_name,
>> +		 const char *slot,
>> +		 const int event),
>> +
>> +	TP_ARGS(port_name, slot, event),
>> +
>> +	TP_STRUCT__entry(
>> +		__string(	port_name,	port_name	)
>> +		__string(	slot,		slot		)
>> +		__field(	int,		event	)
>> +	),
>> +
>> +	TP_fast_assign(
>> +		__assign_str(port_name);
>> +		__assign_str(slot);
>> +		__entry->event = event;
>> +	),
>> +
>> +	TP_printk("%s slot:%s, event:%s\n",
>> +		__get_str(port_name),
>> +		__get_str(slot),
>> +		__print_symbolic(__entry->event, PCI_HOTPLUG_EVENT)
>> +	)
>> +);
>> +
>> +#endif /* _TRACE_HW_EVENT_PCI_HP_H */
>> +
>> +#undef TRACE_INCLUDE_PATH
>> +#define TRACE_INCLUDE_PATH  ../../drivers/pci/hotplug
>> +#undef TRACE_INCLUDE_FILE
>> +#define TRACE_INCLUDE_FILE trace
>> +
>> +/* This part must be outside protection */
>> +#include <trace/define_trace.h>
>> diff --git a/include/uapi/linux/pci.h b/include/uapi/linux/pci.h
>> index a769eefc5139..4f150028965d 100644
>> --- a/include/uapi/linux/pci.h
>> +++ b/include/uapi/linux/pci.h
>> @@ -39,4 +39,11 @@
>>   #define PCIIOC_MMAP_IS_MEM	(PCIIOC_BASE | 0x02)	/* Set mmap state to MEM space. */
>>   #define PCIIOC_WRITE_COMBINE	(PCIIOC_BASE | 0x03)	/* Enable/disable write-combining. */
>>   
>> +enum pci_hotplug_event {
>> +	PCI_HOTPLUG_LINK_UP,
>> +	PCI_HOTPLUG_LINK_DOWN,
>> +	PCI_HOTPLUG_CARD_PRESENT,
>> +	PCI_HOTPLUG_CARD_NOT_PRESENT,
>> +};
> 
> Instead of defining the enum as you did above, if you have the define of
> the enums here, you could do:
> 
> #define PCI_HOTPLUG_EVENT					\
> 	EM(PCI_HOTPLUG_LINK_UP,			"Link Up")	\
> 	EM(PCI_HOTPLUG_LINK_DOWN,		"Link Down")	\
> 	EM(PCI_HOTPLUG_CARD_PRESENT,		"Card present")	\
> 	EMe(PCI_HOTPLUG_CARD_NOT_PRESENT,	"Card not present")
> 
> #undef EM
> #undef EMe
> #define EM(a, b)	a,
> #define EMe(a, b)	a,
> 
> enum pci_hotplug_event {
> 	PCI_HOTPLUG_EVENT
> };
> 
> Then you only have one place to worry about adding new enums ;-)

Will do.


> 
> -- Steve
> 

Thanks for valuable comments.

Best Regards,
Shuai

Patchew 2.1-devel-b67e4c2

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