5291099e0f
The lack of a definition for this counter is what initially prompted me
to investigate a problem which really manifested itself as the previous
change, "net: mscc: ocelot: fix transfer from region->buf to ocelot->stats".
When TX_MM_HOLD is defined in enum ocelot_stat but not in struct
ocelot_stat_layout ocelot_mm_stats_layout, this creates a hole, which
due to the aforementioned bug, makes all counters following TX_MM_HOLD
be recorded off by one compared to their correct position. So for
example, a non-zero TX_PMAC_OCTETS would be reported as TX_MERGE_FRAGMENTS,
TX_PMAC_UNICAST would be reported as TX_PMAC_OCTETS, TX_PMAC_64 would be
reported as TX_PMAC_PAUSE, etc etc. This is because the size of the hole
(1) is much smaller than the size of the region, so the phenomenon where
the stats are off-by-one, rather than lost, prevails.
However, the phenomenon where stats are lost can be seen too, for
example with DROP_LOCAL, which is at the beginning of its own region
(offset 0x000400 vs the previous 0x0002b0 constitutes a discontinuity).
This is also reported as off by one and saved to TX_PMAC_1527_MAX, but
that counter is not reported to the unstructured "ethtool -S", as
opposed to DROP_LOCAL which is (as "drop_local").
Fixes: ab3f97a9610a ("net: mscc: ocelot: export ethtool MAC Merge stats for Felix VSC9959")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.