When displaying a rate through debugfs minstrel_ht guesses its flags
comparing group indexes.  Since 3ec373c4 ("mac80211: minstrel_ht:
include type (cck/ht) in rates flag"), the rate flags of interest are
present in the mcs_group-s, so use it.
While improving the code, this also fixes a smatch false positive
"error: testing array offset 'i' after use" in minstrel_ht_stats_dump.
This warning only triggers after 9208247d ("mac80211: minstrel_ht:
add basic support for VHT rates <= 3SS@80MHz") with
CONFIG_MAC80211_RC_MINSTREL_VHT unset because then MINSTREL_VHT_GROUP_0
is above MINSTREL_GROUPS_NB and smatch only barks when the "testing
array offset" seems to prevent possible out of bonds accesses (which
does not happen here since i < ARRAY_SIZE(mi->groups)).
Signed-off-by: NKarl Beldan <karl.beldan@rivierawaves.com>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

When the new CONFIG_MAC80211_RC_MINSTREL_VHT is not set (default 'N'),
there is no behavioral change including in sampling and MCS_GROUP_RATES
remains 8.
Otherwise MCS_GROUP_RATES is 10, and a module parameter *vht_only*
(default 'true'), restricts the rates selection to VHT when VHT is
supported.

Regarding the debugfs stats buffer:
It is explicitly increased from 8k to 32k to fit every rates incl. when
both HT and VHT rates are enabled, as for the format, before:
type           rate     tpt eprob *prob ret  *ok(*cum)        ok(      cum)
HT20/LGI ABCDP MCS0     0.0   0.0   0.0   1    0(   0)         0(        0)
after:
 type           rate      tpt eprob *prob ret  *ok(*cum)        ok(      cum)
 HT20/LGI ABCDP MCS0      0.0   0.0   0.0   1    0(   0)         0(        0)
VHT40/LGI       MCS5/2    0.0   0.0   0.0   0    0(   0)         0(        0)
Signed-off-by: NKarl Beldan <karl.beldan@rivierawaves.com>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

No functional change.
Signed-off-by: NKarl Beldan <karl.beldan@rivierawaves.com>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

ATM an HT rc_stats line is 106 chars.
Times 8(MCS_GROUP_RATES)*3(SS)*2(GI)*2(BW) + CCK(4), i.e. x100, this is
well above the current 8192 - sizeof(*ms) currently allocated.

Fix this by squeezing the output as follows (not that we're short on
memory but this also improves readability and range, the new format adds
one more digit to *ok/*cum and ok/cum):

- Before (HT) (106 ch):
type           rate     throughput  ewma prob   this prob  retry   this succ/attempt   success    attempts
CCK/LP          5.5M           0.0        0.0         0.0      0              0(  0)         0           0
HT20/LGI ABCDP MCS0            0.0        0.0         0.0      1              0(  0)         0           0
- After (75 ch):
type           rate     tpt eprob *prob ret  *ok(*cum)        ok(      cum)
CCK/LP          5.5M    0.0   0.0   0.0   0    0(   0)         0(        0)
HT20/LGI ABCDP MCS0     0.0   0.0   0.0   1    0(   0)         0(        0)

- Align non-HT format Before (non-HT) (83 ch):
rate      throughput  ewma prob  this prob  this succ/attempt   success    attempts
ABCDP  6         0.0        0.0        0.0             0(  0)         0           0
      54         0.0        0.0        0.0             0(  0)         0           0
- After (61 ch):
rate          tpt eprob *prob  *ok(*cum)        ok(      cum)
ABCDP  1      0.0   0.0   0.0    0(   0)         0(        0)
      54      0.0   0.0   0.0    0(   0)         0(        0)

*This also adds dynamic checks for overflow, lowers the size of the
non-HT request (allowing > 30 entries) and replaces the buddy-rounded
allocations (s/sizeof(*ms) + 8192/8192).
Signed-off-by: NKarl Beldan <karl.beldan@rivierawaves.com>
Acked-by: NFelix Fietkau <nbd@openwrt.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This patch improves the way minstrel_ht sorts rates according to throughput
and success probability. 3 FOR-loops across the entire rate and mcs group set
in function minstrel_ht_update_stats() which where used to determine the
fastest, second fastest and most robust rate are reduced to 2 FOR-loop.

The sorted list of rates according throughput is extended to the best four
rates as we need them in upcoming joint rate and power control. The sorting
is done via the new function minstrel_ht_sort_best_tp_rates(). The annotation
of those 4 best throughput rates in the debugfs file rc-stats is changes to:
"A,B,C,D", where A is the fastest rate and C the 4th fastest.
Signed-off-by: NThomas Huehn <thomas@net.t-labs.tu-berlin.de>
Tested-by: NStefan Venz <ikstream86@gmail.com>
Acked-by: NFelix Fietkau <nbd@openwrt.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Consecutive MCSes in [8*(NSS-1)->8*NSS[ have the same number NSS of
streams (except for MCS32 which is mishandled ATM).
ATM minstrel_ht uses MCS_GROUP_RATES in place of this 8 modulus.
This change replaces such occurences and by doing so allows for different
values of MCS_GROUP_RATES (e.g to cope with VHT MCS8,9).
Signed-off-by: NKarl Beldan <karl.beldan@rivierawaves.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

When MCS rates start to get bad in 2.4 GHz because of long range or
strong interference, CCK rates can be a lot more robust.

This patch adds a pseudo MCS group containing CCK rates (long preamble
in the lower 4 slots, short preamble in the upper slots).
Signed-off-by: NFelix Fietkau <nbd@openwrt.org>
[make minstrel_ht_get_stats static]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Signed-off-by: NFelix Fietkau <nbd@openwrt.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

These files are non modular, but need to export symbols using
the macros now living in export.h -- call out the include so
that things won't break when we remove the implicit presence
of module.h from everywhere.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

No need for seek here, so let's just use nonseekable_open.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>
Acked-by: NFelix Fietkau <nbd@openwrt.org>

Signed-off-by: NFelix Fietkau <nbd@openwrt.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>