Re: [PATCH] iscsi: Capture iscsi debug messages using tracepoints

[Lee Duncan <lduncan-IBi9RG/b67k@public.gmane.org>]

On 11/21/18 9:04 AM, fred.herard-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org wrote:
> From: Fred Herard <fred.herard-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> 
> This commit enhances iscsi initiator modules to capture iscsi debug messages
> using linux kernel tracepoint facility:
> 
> https://www.kernel.org/doc/Documentation/trace/tracepoints.txt
> 
> The following tracepoint events have been created under the iscsi tracepoint
> event group:
> 
> iscsi_dbg_conn - to capture connection debug messages (libiscsi module)
> iscsi_dbg_session - to capture session debug messages (libiscsi module)
> iscsi_dbg_eh - to capture error handling debug messages (libiscsi module)
> iscsi_dbg_tcp - to capture iscsi tcp debug messages (libiscsi_tcp module)
> iscsi_dbg_sw_tcp - to capture iscsi sw tcp debug messages (iscsi_tcp module)
> iscsi_dbg_trans_session - to cpature iscsi trasnsport sess debug messages
> 	(scsi_transport_iscsi module)
> iscsi_dbg_trans_conn - to capture iscsi tansport conn debug messages
> 	(scsi_transport_iscsi module)
> 
> Signed-off-by: Fred Herard <fred.herard-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> Reviewed-by: Rajan Shanmugavelu <rajan.shanmugavelu-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> ---
>  drivers/scsi/iscsi_tcp.c            |   4 ++
>  drivers/scsi/libiscsi.c             |  10 +++
>  drivers/scsi/libiscsi_tcp.c         |   4 ++
>  drivers/scsi/scsi_transport_iscsi.c |  34 ++++++++-
>  include/trace/events/iscsi.h        | 107 ++++++++++++++++++++++++++++
>  5 files changed, 158 insertions(+), 1 deletion(-)
>  create mode 100644 include/trace/events/iscsi.h
> 
> diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
> index e11eff6b0e97..cf6475af72b1 100644
> --- a/drivers/scsi/iscsi_tcp.c
> +++ b/drivers/scsi/iscsi_tcp.c
> @@ -44,6 +44,7 @@
>  #include <scsi/scsi_host.h>
>  #include <scsi/scsi.h>
>  #include <scsi/scsi_transport_iscsi.h>
> +#include <trace/events/iscsi.h>
>  
>  #include "iscsi_tcp.h"
>  
> @@ -72,6 +73,9 @@ MODULE_PARM_DESC(debug_iscsi_tcp, "Turn on debugging for iscsi_tcp module "
>  			iscsi_conn_printk(KERN_INFO, _conn,	\
>  					     "%s " dbg_fmt,	\
>  					     __func__, ##arg);	\
> +		iscsi_dbg_trace(trace_iscsi_dbg_sw_tcp,		\
> +				&(_conn)->cls_conn->dev,	\
> +				"%s " dbg_fmt, __func__, ##arg);\
>  	} while (0);
>  
>  
> diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
> index cf8a15e54d83..088e90308c1f 100644
> --- a/drivers/scsi/libiscsi.c
> +++ b/drivers/scsi/libiscsi.c
> @@ -40,6 +40,7 @@
>  #include <scsi/scsi_transport.h>
>  #include <scsi/scsi_transport_iscsi.h>
>  #include <scsi/libiscsi.h>
> +#include <trace/events/iscsi.h>
>  
>  static int iscsi_dbg_lib_conn;
>  module_param_named(debug_libiscsi_conn, iscsi_dbg_lib_conn, int,
> @@ -68,6 +69,9 @@ MODULE_PARM_DESC(debug_libiscsi_eh,
>  			iscsi_conn_printk(KERN_INFO, _conn,	\
>  					     "%s " dbg_fmt,	\
>  					     __func__, ##arg);	\
> +		iscsi_dbg_trace(trace_iscsi_dbg_conn,		\
> +				&(_conn)->cls_conn->dev,	\
> +				"%s " dbg_fmt, __func__, ##arg);\
>  	} while (0);
>  
>  #define ISCSI_DBG_SESSION(_session, dbg_fmt, arg...)			\
> @@ -76,6 +80,9 @@ MODULE_PARM_DESC(debug_libiscsi_eh,
>  			iscsi_session_printk(KERN_INFO, _session,	\
>  					     "%s " dbg_fmt,		\
>  					     __func__, ##arg);		\
> +		iscsi_dbg_trace(trace_iscsi_dbg_session, 		\
> +				&(_session)->cls_session->dev,		\
> +				"%s " dbg_fmt, __func__, ##arg);	\
>  	} while (0);
>  
>  #define ISCSI_DBG_EH(_session, dbg_fmt, arg...)				\
> @@ -84,6 +91,9 @@ MODULE_PARM_DESC(debug_libiscsi_eh,
>  			iscsi_session_printk(KERN_INFO, _session,	\
>  					     "%s " dbg_fmt,		\
>  					     __func__, ##arg);		\
> +		iscsi_dbg_trace(trace_iscsi_dbg_eh,			\
> +				&(_session)->cls_session->dev,		\
> +				"%s " dbg_fmt, __func__, ##arg);	\
>  	} while (0);
>  
>  inline void iscsi_conn_queue_work(struct iscsi_conn *conn)
> diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c
> index 63a1d69ff515..d641a72ae033 100644
> --- a/drivers/scsi/libiscsi_tcp.c
> +++ b/drivers/scsi/libiscsi_tcp.c
> @@ -43,6 +43,7 @@
>  #include <scsi/scsi_host.h>
>  #include <scsi/scsi.h>
>  #include <scsi/scsi_transport_iscsi.h>
> +#include <trace/events/iscsi.h>
>  
>  #include "iscsi_tcp.h"
>  
> @@ -65,6 +66,9 @@ MODULE_PARM_DESC(debug_libiscsi_tcp, "Turn on debugging for libiscsi_tcp "
>  			iscsi_conn_printk(KERN_INFO, _conn,	\
>  					     "%s " dbg_fmt,	\
>  					     __func__, ##arg);	\
> +		iscsi_dbg_trace(trace_iscsi_dbg_tcp,		\
> +				&(_conn)->cls_conn->dev,	\
> +				"%s " dbg_fmt, __func__, ##arg);\
>  	} while (0);
>  
>  static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
> diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
> index f6542c159ed6..58e0310ce258 100644
> --- a/drivers/scsi/scsi_transport_iscsi.c
> +++ b/drivers/scsi/scsi_transport_iscsi.c
> @@ -37,6 +37,18 @@
>  
>  #define ISCSI_TRANSPORT_VERSION "2.0-870"
>  
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/iscsi.h>
> +
> +/*
> + * Export tracepoint symbols to be used by other modules.
> + */
> +EXPORT_TRACEPOINT_SYMBOL_GPL(iscsi_dbg_conn);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(iscsi_dbg_eh);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(iscsi_dbg_session);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(iscsi_dbg_tcp);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(iscsi_dbg_sw_tcp);
> +
>  static int dbg_session;
>  module_param_named(debug_session, dbg_session, int,
>  		   S_IRUGO | S_IWUSR);
> @@ -59,6 +71,9 @@ MODULE_PARM_DESC(debug_conn,
>  			iscsi_cls_session_printk(KERN_INFO, _session,	\
>  						 "%s: " dbg_fmt,	\
>  						 __func__, ##arg);	\
> +		iscsi_dbg_trace(trace_iscsi_dbg_trans_session,		\
> +				&(_session)->dev,			\
> +				"%s " dbg_fmt, __func__, ##arg);	\
>  	} while (0);
>  
>  #define ISCSI_DBG_TRANS_CONN(_conn, dbg_fmt, arg...)			\
> @@ -66,7 +81,10 @@ MODULE_PARM_DESC(debug_conn,
>  		if (dbg_conn)						\
>  			iscsi_cls_conn_printk(KERN_INFO, _conn,		\
>  					      "%s: " dbg_fmt,		\
> -					      __func__, ##arg);	\
> +					      __func__, ##arg);		\
> +		iscsi_dbg_trace(trace_iscsi_dbg_trans_conn,		\
> +				&(_conn)->dev,				\
> +				"%s " dbg_fmt, __func__, ##arg);	\
>  	} while (0);
>  
>  struct iscsi_internal {
> @@ -4497,6 +4515,20 @@ int iscsi_unregister_transport(struct iscsi_transport *tt)
>  }
>  EXPORT_SYMBOL_GPL(iscsi_unregister_transport);
>  
> +void iscsi_dbg_trace(void (*trace)(struct device *dev, struct va_format *),
> +		     struct device *dev, const char *fmt, ...)
> +{
> +	struct va_format vaf;
> +	va_list args;
> +
> +	va_start(args, fmt);
> +	vaf.fmt = fmt;
> +	vaf.va = &args;
> +	trace(dev, &vaf);
> +	va_end(args);
> +}
> +EXPORT_SYMBOL_GPL(iscsi_dbg_trace);
> +
>  static __init int iscsi_transport_init(void)
>  {
>  	int err;
> diff --git a/include/trace/events/iscsi.h b/include/trace/events/iscsi.h
> new file mode 100644
> index 000000000000..87408faf6e4e
> --- /dev/null
> +++ b/include/trace/events/iscsi.h
> @@ -0,0 +1,107 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM iscsi
> +
> +#if !defined(_TRACE_ISCSI_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_ISCSI_H
> +
> +#include <linux/tracepoint.h>
> +
> +/* max debug message length */
> +#define ISCSI_MSG_MAX	256
> +
> +/*
> + * Declare tracepoint helper function.
> + */
> +void iscsi_dbg_trace(void (*trace)(struct device *dev, struct va_format *),
> +		     struct device *dev, const char *fmt, ...);
> +
> +/*
> + * Declare event class for iscsi debug messages.
> + */
> +DECLARE_EVENT_CLASS(iscsi_log_msg,
> +
> +	TP_PROTO(struct device *dev, struct va_format *vaf),
> +
> +	TP_ARGS(dev, vaf),
> +
> +	TP_STRUCT__entry(
> +		__string(dname, 	dev_name(dev)		)
> +		__dynamic_array(char,	msg, ISCSI_MSG_MAX	)
> +	),
> +
> +	TP_fast_assign(
> +		__assign_str(dname, dev_name(dev));
> +		vsnprintf(__get_str(msg), ISCSI_MSG_MAX, vaf->fmt, *vaf->va);
> +	),
> +
> +	TP_printk("%s: %s",__get_str(dname),  __get_str(msg)
> +	)
> +);
> +
> +/*
> + * Define event to capture iscsi connection debug messages.
> + */
> +DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_conn,
> +	TP_PROTO(struct device *dev, struct va_format *vaf),
> +
> +	TP_ARGS(dev, vaf)
> +);
> +
> +/*
> + * Define event to capture iscsi session debug messages.
> + */
> +DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_session,
> +	TP_PROTO(struct device *dev, struct va_format *vaf),
> +
> +	TP_ARGS(dev, vaf)
> +);
> +
> +/*
> + * Define event to capture iscsi error handling debug messages.
> + */
> +DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_eh,
> +        TP_PROTO(struct device *dev, struct va_format *vaf),
> +
> +        TP_ARGS(dev, vaf)
> +);
> +
> +/*
> + * Define event to capture iscsi tcp debug messages.
> + */
> +DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_tcp,
> +        TP_PROTO(struct device *dev, struct va_format *vaf),
> +
> +        TP_ARGS(dev, vaf)
> +);
> +
> +/*
> + * Define event to capture iscsi sw tcp debug messages.
> + */
> +DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_sw_tcp,
> +	TP_PROTO(struct device *dev, struct va_format *vaf),
> +
> +	TP_ARGS(dev, vaf)
> +);
> +
> +/*
> + * Define event to capture iscsi transport session debug messages.
> + */
> +DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_trans_session,
> +	TP_PROTO(struct device *dev, struct va_format *vaf),
> +
> +	TP_ARGS(dev, vaf)
> +);
> +
> +/*
> + * Define event to capture iscsi transport connection debug messages.
> + */
> +DEFINE_EVENT(iscsi_log_msg, iscsi_dbg_trans_conn,
> +	TP_PROTO(struct device *dev, struct va_format *vaf),
> +
> +	TP_ARGS(dev, vaf)
> +);
> +
> +#endif /* _TRACE_ISCSI_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
> 

Reviewed-by: Lee Duncan <lduncan-IBi9RG/b67k@public.gmane.org>

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