iwlwifi: mvm: do not trust NSSN for amsdu sub-frames
We cannot trust NSSN for AMSDU sub-frames that are not the
last.
The reason is that NSSN advances on the first sub-frame,
and may cause the reorder buffer to advance before all the
sub-frames arrive.
Example:
Reorder buffer contains SN 0 & 2.
We receive AMSDU with SN 1 and NSSN for first sub frame 3.
The result us that driver releases SN 0,1, 2.
When sub-frame 1 arrives - reorder buffer is already ahead and
it will be dropped.
If the last sub-frame is not on this queue - we will get frame
release notification with up to date NSSN.
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
index ac2c571..0f26c70 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
@@ -587,6 +587,8 @@
struct sk_buff *tail;
u32 reorder = le32_to_cpu(desc->reorder_data);
bool amsdu = desc->mac_flags2 & IWL_RX_MPDU_MFLG2_AMSDU;
+ bool last_subframe =
+ desc->amsdu_info & IWL_RX_MPDU_AMSDU_LAST_SUBFRAME;
u8 tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
u8 sub_frame_idx = desc->amsdu_info &
IWL_RX_MPDU_AMSDU_SUBFRAME_IDX_MASK;
@@ -651,7 +653,8 @@
/* release immediately if allowed by nssn and no stored frames */
if (!buffer->num_stored && ieee80211_sn_less(sn, nssn)) {
if (iwl_mvm_is_sn_less(buffer->head_sn, nssn,
- buffer->buf_size))
+ buffer->buf_size) &&
+ (!amsdu || last_subframe))
buffer->head_sn = nssn;
/* No need to update AMSDU last SN - we are moving the head */
spin_unlock_bh(&buffer->lock);
@@ -685,7 +688,20 @@
buffer->last_sub_index = sub_frame_idx;
}
- iwl_mvm_release_frames(mvm, sta, napi, buffer, nssn);
+ /*
+ * We cannot trust NSSN for AMSDU sub-frames that are not the last.
+ * The reason is that NSSN advances on the first sub-frame, and may
+ * cause the reorder buffer to advance before all the sub-frames arrive.
+ * Example: reorder buffer contains SN 0 & 2, and we receive AMSDU with
+ * SN 1. NSSN for first sub frame will be 3 with the result of driver
+ * releasing SN 0,1, 2. When sub-frame 1 arrives - reorder buffer is
+ * already ahead and it will be dropped.
+ * If the last sub-frame is not on this queue - we will get frame
+ * release notification with up to date NSSN.
+ */
+ if (!amsdu || last_subframe)
+ iwl_mvm_release_frames(mvm, sta, napi, buffer, nssn);
+
spin_unlock_bh(&buffer->lock);
return true;