Mesh HWMP module will be able to rely on the HW
RC algorithm if it exists, for path metric calculations.

This allows the metric calculation mechanism to calculate
a correct metric, based on PER and last TX rate both via
HW RC algorithm if it exists or via parameters collected
by the SW.

Signed-off-by: Maxim Altshul <redacted>
---
Changed the function to return u32, I agree that this
is much clearer.
As for the rate, two things:
1. I had to divide the returned value by 100, since
drv_get_expected_throughput returns values in units of Kbps.
On the contrary, the function cfg80211_calculate_bitrate
returns in units of 100Kbps, so a correction is needed.
2. Why return the value into rate?
As I understand, rate here is actually bitrate,
and so, we have two possible outcomes:
- A SW/HW RC algo does exist, and an estimated throughput is
returned. err is set to 0 (as it is already included in the RC algo)
and the airtime is calculated using the estimated throughput.
- A SW/HW RC algo does not exist, and thus the regular calculation
takes place, in which an estimated throughput is calculated
using the bitrate and the err parameter.
From this calculation the airtime is calculated.

 net/mac80211/mesh_hwmp.c | 25 +++++++++++++++++--------
 net/mac80211/sta_info.c  | 23 +++++++++++++++++++----
 net/mac80211/sta_info.h  |  2 ++
 3 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index c6be0b4..ad67f46 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c

@@ -322,19 +322,28 @@ static u32 airtime_link_metric_get(struct

ieee80211_local *local,
 	int device_constant = 1 << ARITH_SHIFT;
 	int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 	int s_unit = 1 << ARITH_SHIFT;
-	int rate, err;
+	int rate = 0, err = 0;