On Tue, Jan 25, 2022 at 6:38 AM Steven Rostedt [off-list ref] wrote:

On Tue, 25 Jan 2022 09:37:02 -0500
Steven Rostedt [off-list ref] wrote:

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+TRACE_EVENT(block_rq_error,
+
+       TP_PROTO(struct request *rq, int error, unsigned int nr_bytes),
+
+       TP_ARGS(rq, error, nr_bytes),
+
+       TP_STRUCT__entry(
+               __field(  dev_t,        dev                     )
+               __string( name,         rq->rq_disk ? rq->rq_disk->disk_name : "?")
+               __field(  sector_t,     sector                  )
+               __field(  unsigned int, nr_sector               )
+               __field(  int,          error                   )
+               __array(  char,         rwbs,   RWBS_LEN        )

Why is the above not "__string" ?

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+       ),
+
+       TP_fast_assign(
+               __entry->dev       = rq->rq_disk ? disk_devt(rq->rq_disk) : 0;
+               __assign_str(name,   rq->rq_disk ? rq->rq_disk->disk_name : "?");

__assign_str() will not work on an __array() type. It only works here
because you added it at the end, but it's just shear luck that it didn't
crash.

Never mind :-p  I see the above is for name which is __string, and the
array is for rwbs which is filled below. I need to finish my first cup of
coffee before reviewing patches.

Never mind. Other than the code restructure, I also found some data
structure (struct request) and function (blk_fill_rwbs) change. I
think I'd better rebase the patch to 5.17-rc1 then resubmit it. Since
there is no fundamental change to the patch, can I keep your
reviewed-by tag?

-- Steve

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+               __entry->sector    = blk_rq_pos(rq);
+               __entry->nr_sector = nr_bytes >> 9;
+               __entry->error     = error;
+
+               blk_fill_rwbs(__entry->rwbs, rq->cmd_flags, nr_bytes);
+       ),
+
+       TP_printk("%d,%d %s %s %llu + %u [%d]",
+                 MAJOR(__entry->dev), MINOR(__entry->dev),
+                 __get_str(name), __entry->rwbs,
+                 (unsigned long long)__entry->sector,
+                 __entry->nr_sector, __entry->error)
+);
+