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iwlwifi: mvm: improve latency when there is a reorder timeout 

When there is a reorder timeout, we may get to a situation
where we have the timeout latency for all the next 64 frames.
This happens since NSSN is behind for a while, and the driver
won't release the frames, since it is not allowed by NSSN.
As a result the frame is stored in the reorder buffer although
there is no hole, and released 100 ms later.
Add a direct comparison to the reorder buffer head, and release
immediately if possible.

For example:
Frame 0 is missed. We receive frame 1, and store it in the buffer.
After 100 ms, frame 1 is released and reorder buffer head is 2.
We then receive frame 2, with NSSN 0, and store it instead of
releasing it.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
This commit is contained in:
Sara Sharon 2017-10-17 12:06:52 +03:00 committed by Luca Coelho
parent 82d2b9a626
commit 14a1f85bdc
1 changed files with 16 additions and 0 deletions
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16
drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
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@ -719,6 +719,22 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
return false;
}
/*
* release immediately if there are no stored frames, and the sn is
* equal to the head.
* This can happen due to reorder timer, where NSSN is behind head_sn.
* When we released everything, and we got the next frame in the
* sequence, according to the NSSN we can't release immediately,
* while technically there is no hole and we can move forward.
*/
if (!buffer->num_stored && sn == buffer->head_sn) {
if (!amsdu || last_subframe)
buffer->head_sn = ieee80211_sn_inc(buffer->head_sn);
/* No need to update AMSDU last SN - we are moving the head */
spin_unlock_bh(&buffer->lock);
return false;
}
index = sn % buffer->buf_size;
/*