Re: [PATCH] i2c: Add message transfer tracepoints for I2C and SMBUS

From: Steven Rostedt
Date: Fri Dec 13 2013 - 13:14:04 EST


On Fri, 13 Dec 2013 17:26:53 +0000
David Howells <dhowells@xxxxxxxxxx> wrote:

> index ed366e145c8d..ca19f4948290 100644
> --- a/include/trace/events/i2c.h
> +++ b/include/trace/events/i2c.h
> @@ -23,42 +23,259 @@
> extern void i2c_transfer_trace_reg(void);
> extern void i2c_transfer_trace_unreg(void);
>
> -TRACE_EVENT_FN(i2c_transfer,
> +/*
> + * __i2c_transfer() write request
> + */
> +TRACE_EVENT_FN(i2c_write,
> TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg,
> - int ret),
> - TP_ARGS(adap, msg, ret),
> + int num),
> + TP_ARGS(adap, msg, num),
> TP_STRUCT__entry(
> - __field( int, adapter_nr )
> + __field(int, adapter_nr )
> + __field(__u16, msg_nr )
> __field(__u16, addr )
> __field(__u16, flags )
> __field(__u16, len )
> - __field(__s16, ret )
> __dynamic_array(__u8, buf, msg->len) ),
> TP_fast_assign(
> __entry->adapter_nr = adap->nr;
> + __entry->msg_nr = num;
> + __entry->addr = msg->addr;
> + __entry->flags = msg->flags;
> + __entry->len = msg->len;
> + memcpy(__get_dynamic_array(buf), msg->buf, msg->len);
> + ),
> + TP_printk("i2c-%d #%u f=%02x a=%02x l=%u [%*phN]",
> + __entry->adapter_nr,
> + __entry->msg_nr,
> + __entry->flags,
> + __entry->addr,
> + __entry->len,
> + __entry->len, __get_dynamic_array(buf)
> + ),
> + i2c_transfer_trace_reg,
> + i2c_transfer_trace_unreg);
> +
> +/*
> + * __i2c_transfer() read request
> + */
> +TRACE_EVENT_FN(i2c_read,
> + TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg,
> + int num),
> + TP_ARGS(adap, msg, num),
> + TP_STRUCT__entry(
> + __field(int, adapter_nr )
> + __field(__u16, msg_nr )
> + __field(__u16, addr )
> + __field(__u16, flags )
> + __field(__u16, len )
> + ),
> + TP_fast_assign(
> + __entry->adapter_nr = adap->nr;
> + __entry->msg_nr = num;
> + __entry->addr = msg->addr;
> + __entry->flags = msg->flags;
> + __entry->len = msg->len;
> + ),
> + TP_printk("i2c-%d #%u f=%02x a=%02x l=%u",
> + __entry->adapter_nr,
> + __entry->msg_nr,
> + __entry->flags,
> + __entry->addr,
> + __entry->len
> + ),
> + i2c_transfer_trace_reg,
> + i2c_transfer_trace_unreg);
> +

Now that you have two tracepoints that are identical, you can use
DECLARE_EVENT_CLASS() and DEFINE_EVENT_FN(). That is:

DECLARE_EVENT_CLASS(i2c_read_write,
TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg,
int num),
TP_ARGS(adap, msg, num),
TP_STRUCT__entry(
__field(int, adapter_nr )
__field(__u16, msg_nr )
__field(__u16, addr )
__field(__u16, flags )
__field(__u16, len )),
TP_fast_assign(
__entry->adapter_nr = adap->nr;
__entry->msg_nr = num;
__entry->addr = msg->addr;
__entry->flags = msg->flags;
__entry->len = msg->len;
),
TP_printk("i2c-%d #%u f=%02x a=%02x l=%u",
__entry->adapter_nr,
__entry->msg_nr,
__entry->flags,
__entry->addr,
__entry->len
)
);

DEFINE_EVENT_FN(i2c_read_write, i2c_read,
TP_PROTO(const struct i2c_adapter *adap, const struct i2c_ msg *msg,
int num),
TP_ARGS(adap, msg, num),
i2c_transfer_trace_reg,
i2c_transfer_trace_unreg);

DEFINE_EVENT_FN(i2c_read_write, i2c_write,
TP_PROTO(const struct i2c_adapter *adap, const struct i2c_ msg *msg,
int num),
TP_ARGS(adap, msg, num),
i2c_transfer_trace_reg,
i2c_transfer_trace_unreg);

This will reduce duplication of code by several kilobytes.


-- Steve

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