iwlwifi: mvm: allocate reorder buffer according to need

Now that we may have up to 256 entries per reorder buffer, and possibly up
to 16 queues, we can use a LOT of memory for this (64k for each station).
Allocate it according to what we need, which is of course much less for HT
stations (only 16k at a max of 16 queues).

However, this comes at the expense of complicating the code a bit to
calculate the right entry structure to use for each frame.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

3 files changed, 90 insertions, 17 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h b/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
index bf25c3ce7c95..52a2f49132e7 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mvm.h
@@ -590,8 +590,6 @@ enum iwl_mvm_tdls_cs_state {
  * @last_amsdu: track last ASMDU SN for duplication detection
  * @last_sub_index: track ASMDU sub frame index for duplication detection
  * @tid: the tid
- * @entries: list of skbs stored
- * @reorder_time: time the packet was stored in the reorder buffer
  * @reorder_timer: timer for frames are in the reorder buffer. For AMSDU
  *	it is the time of last received sub-frame
  * @removed: prevent timer re-arming
@@ -608,8 +606,6 @@ struct iwl_mvm_reorder_buffer {
 	u16 last_amsdu;
 	u8 last_sub_index;
 	u8 tid;
-	struct sk_buff_head entries[IEEE80211_MAX_AMPDU_BUF];
-	unsigned long reorder_time[IEEE80211_MAX_AMPDU_BUF];
 	struct timer_list reorder_timer;
 	bool removed;
 	bool valid;
@@ -618,15 +614,38 @@ struct iwl_mvm_reorder_buffer {
 } ____cacheline_aligned_in_smp;
 
 /**
+ * struct _iwl_mvm_reorder_buf_entry - reorder buffer entry per-queue/per-seqno
+ * @frames: list of skbs stored
+ * @reorder_time: time the packet was stored in the reorder buffer
+ */
+struct _iwl_mvm_reorder_buf_entry {
+	struct sk_buff_head frames;
+	unsigned long reorder_time;
+};
+
+/* make this indirection to get the aligned thing */
+struct iwl_mvm_reorder_buf_entry {
+	struct _iwl_mvm_reorder_buf_entry e;
+}
+#ifndef __CHECKER__
+/* sparse doesn't like this construct: "bad integer constant expression" */
+__aligned(roundup_pow_of_two(sizeof(struct _iwl_mvm_reorder_buf_entry)))
+#endif
+;
+
+/**
  * struct iwl_mvm_baid_data - BA session data
  * @sta_id: station id
  * @tid: tid of the session
  * @baid baid of the session
  * @timeout: the timeout set in the addba request
+ * @entries_per_queue: # of buffers per queue, this actually gets
+ *	aligned up to avoid cache line sharing between queues
  * @last_rx: last rx jiffies, updated only if timeout passed from last update
  * @session_timer: timer to check if BA session expired, runs at 2 * timeout
  * @mvm: mvm pointer, needed for timer context
  * @reorder_buf: reorder buffer, allocated per queue
+ * @reorder_buf_data: data
  */
 struct iwl_mvm_baid_data {
 	struct rcu_head rcu_head;
@@ -634,12 +653,22 @@ struct iwl_mvm_baid_data {
 	u8 tid;
 	u8 baid;
 	u16 timeout;
+	u16 entries_per_queue;
 	unsigned long last_rx;
 	struct timer_list session_timer;
 	struct iwl_mvm *mvm;
-	struct iwl_mvm_reorder_buffer reorder_buf[];
+	struct iwl_mvm_reorder_buffer reorder_buf[IWL_MAX_RX_HW_QUEUES];
+	struct iwl_mvm_reorder_buf_entry entries[];
 };
 
+static inline struct iwl_mvm_baid_data *
+iwl_mvm_baid_data_from_reorder_buf(struct iwl_mvm_reorder_buffer *buf)
+{
+	return (void *)((u8 *)buf -
+			offsetof(struct iwl_mvm_baid_data, reorder_buf) -
+			sizeof(*buf) * buf->queue);
+}
+
 /*
  * enum iwl_mvm_queue_status - queue status
  * @IWL_MVM_QUEUE_FREE: the queue is not allocated nor reserved
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
index 5e679859f948..bb1a1ac9f6ed 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c
@@ -412,6 +412,11 @@ static void iwl_mvm_release_frames(struct iwl_mvm *mvm,
 				   struct iwl_mvm_reorder_buffer *reorder_buf,
 				   u16 nssn)
 {
+	struct iwl_mvm_baid_data *baid_data =
+		iwl_mvm_baid_data_from_reorder_buf(reorder_buf);
+	struct iwl_mvm_reorder_buf_entry *entries =
+		&baid_data->entries[reorder_buf->queue *
+				    baid_data->entries_per_queue];
 	u16 ssn = reorder_buf->head_sn;
 
 	lockdep_assert_held(&reorder_buf->lock);
@@ -422,7 +427,7 @@ static void iwl_mvm_release_frames(struct iwl_mvm *mvm,
 
 	while (iwl_mvm_is_sn_less(ssn, nssn, reorder_buf->buf_size)) {
 		int index = ssn % reorder_buf->buf_size;
-		struct sk_buff_head *skb_list = &reorder_buf->entries[index];
+		struct sk_buff_head *skb_list = &entries[index].e.frames;
 		struct sk_buff *skb;
 
 		ssn = ieee80211_sn_inc(ssn);
@@ -445,11 +450,11 @@ set_timer:
 	if (reorder_buf->num_stored && !reorder_buf->removed) {
 		u16 index = reorder_buf->head_sn % reorder_buf->buf_size;
 
-		while (skb_queue_empty(&reorder_buf->entries[index]))
+		while (skb_queue_empty(&entries[index].e.frames))
 			index = (index + 1) % reorder_buf->buf_size;
 		/* modify timer to match next frame's expiration time */
 		mod_timer(&reorder_buf->reorder_timer,
-			  reorder_buf->reorder_time[index] + 1 +
+			  entries[index].e.reorder_time + 1 +
 			  RX_REORDER_BUF_TIMEOUT_MQ);
 	} else {
 		del_timer(&reorder_buf->reorder_timer);
@@ -459,6 +464,10 @@ set_timer:
 void iwl_mvm_reorder_timer_expired(unsigned long data)
 {
 	struct iwl_mvm_reorder_buffer *buf = (void *)data;
+	struct iwl_mvm_baid_data *baid_data =
+		iwl_mvm_baid_data_from_reorder_buf(buf);
+	struct iwl_mvm_reorder_buf_entry *entries =
+		&baid_data->entries[buf->queue * baid_data->entries_per_queue];
 	int i;
 	u16 sn = 0, index = 0;
 	bool expired = false;
@@ -474,7 +483,7 @@ void iwl_mvm_reorder_timer_expired(unsigned long data)
 	for (i = 0; i < buf->buf_size ; i++) {
 		index = (buf->head_sn + i) % buf->buf_size;
 
-		if (skb_queue_empty(&buf->entries[index])) {
+		if (skb_queue_empty(&entries[index].e.frames)) {
 			/*
 			 * If there is a hole and the next frame didn't expire
 			 * we want to break and not advance SN
@@ -482,7 +491,8 @@ void iwl_mvm_reorder_timer_expired(unsigned long data)
 			cont = false;
 			continue;
 		}
-		if (!cont && !time_after(jiffies, buf->reorder_time[index] +
+		if (!cont &&
+		    !time_after(jiffies, entries[index].e.reorder_time +
 					 RX_REORDER_BUF_TIMEOUT_MQ))
 			break;
 
@@ -515,7 +525,7 @@ void iwl_mvm_reorder_timer_expired(unsigned long data)
 		 * accordingly to this frame.
 		 */
 		mod_timer(&buf->reorder_timer,
-			  buf->reorder_time[index] +
+			  entries[index].e.reorder_time +
 			  1 + RX_REORDER_BUF_TIMEOUT_MQ);
 	}
 	spin_unlock(&buf->lock);
@@ -610,6 +620,7 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
 	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;
+	struct iwl_mvm_reorder_buf_entry *entries;
 	int index;
 	u16 nssn, sn;
 	u8 baid;
@@ -660,6 +671,7 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
 		IWL_RX_MPDU_REORDER_SN_SHIFT;
 
 	buffer = &baid_data->reorder_buf[queue];
+	entries = &baid_data->entries[queue * baid_data->entries_per_queue];
 
 	spin_lock_bh(&buffer->lock);
 
@@ -716,7 +728,7 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
 	 * If it is the same SN then if the subframe index is incrementing it
 	 * is the same AMSDU - otherwise it is a retransmission.
 	 */
-	tail = skb_peek_tail(&buffer->entries[index]);
+	tail = skb_peek_tail(&entries[index].e.frames);
 	if (tail && !amsdu)
 		goto drop;
 	else if (tail && (sn != buffer->last_amsdu ||
@@ -724,9 +736,9 @@ static bool iwl_mvm_reorder(struct iwl_mvm *mvm,
 		goto drop;
 
 	/* put in reorder buffer */
-	__skb_queue_tail(&buffer->entries[index], skb);
+	__skb_queue_tail(&entries[index].e.frames, skb);
 	buffer->num_stored++;
-	buffer->reorder_time[index] = jiffies;
+	entries[index].e.reorder_time = jiffies;
 
 	if (amsdu) {
 		buffer->last_amsdu = sn;
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
index 282424f40c43..43e18e75ef42 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
@@ -2104,6 +2104,8 @@ static void iwl_mvm_free_reorder(struct iwl_mvm *mvm,
 		int j;
 		struct iwl_mvm_reorder_buffer *reorder_buf =
 			&data->reorder_buf[i];
+		struct iwl_mvm_reorder_buf_entry *entries =
+			&data->entries[i * data->entries_per_queue];
 
 		spin_lock_bh(&reorder_buf->lock);
 		if (likely(!reorder_buf->num_stored)) {
@@ -2119,7 +2121,7 @@ static void iwl_mvm_free_reorder(struct iwl_mvm *mvm,
 		WARN_ON(1);
 
 		for (j = 0; j < reorder_buf->buf_size; j++)
-			__skb_queue_purge(&reorder_buf->entries[j]);
+			__skb_queue_purge(&entries[j].e.frames);
 		/*
 		 * Prevent timer re-arm. This prevents a very far fetched case
 		 * where we timed out on the notification. There may be prior
@@ -2144,6 +2146,8 @@ static void iwl_mvm_init_reorder_buffer(struct iwl_mvm *mvm,
 	for (i = 0; i < mvm->trans->num_rx_queues; i++) {
 		struct iwl_mvm_reorder_buffer *reorder_buf =
 			&data->reorder_buf[i];
+		struct iwl_mvm_reorder_buf_entry *entries =
+			&data->entries[i * data->entries_per_queue];
 		int j;
 
 		reorder_buf->num_stored = 0;
@@ -2161,7 +2165,7 @@ static void iwl_mvm_init_reorder_buffer(struct iwl_mvm *mvm,
 		reorder_buf->tid = data->tid;
 		reorder_buf->valid = false;
 		for (j = 0; j < reorder_buf->buf_size; j++)
-			__skb_queue_head_init(&reorder_buf->entries[j]);
+			__skb_queue_head_init(&entries[j].e.frames);
 	}
 }
 
@@ -2182,16 +2186,44 @@ int iwl_mvm_sta_rx_agg(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
 	}
 
 	if (iwl_mvm_has_new_rx_api(mvm) && start) {
+		u16 reorder_buf_size = buf_size * sizeof(baid_data->entries[0]);
+
+		/* sparse doesn't like the __align() so don't check */
+#ifndef __CHECKER__
+		/*
+		 * The division below will be OK if either the cache line size
+		 * can be divided by the entry size (ALIGN will round up) or if
+		 * if the entry size can be divided by the cache line size, in
+		 * which case the ALIGN() will do nothing.
+		 */
+		BUILD_BUG_ON(SMP_CACHE_BYTES % sizeof(baid_data->entries[0]) &&
+			     sizeof(baid_data->entries[0]) % SMP_CACHE_BYTES);
+#endif
+
+		/*
+		 * Upward align the reorder buffer size to fill an entire cache
+		 * line for each queue, to avoid sharing cache lines between
+		 * different queues.
+		 */
+		reorder_buf_size = ALIGN(reorder_buf_size, SMP_CACHE_BYTES);
+
 		/*
 		 * Allocate here so if allocation fails we can bail out early
 		 * before starting the BA session in the firmware
 		 */
 		baid_data = kzalloc(sizeof(*baid_data) +
 				    mvm->trans->num_rx_queues *
-				    sizeof(baid_data->reorder_buf[0]),
+				    reorder_buf_size,
 				    GFP_KERNEL);
 		if (!baid_data)
 			return -ENOMEM;
+
+		/*
+		 * This division is why we need the above BUILD_BUG_ON(),
+		 * if that doesn't hold then this will not be right.
+		 */
+		baid_data->entries_per_queue =
+			reorder_buf_size / sizeof(baid_data->entries[0]);
 	}
 
 	cmd.mac_id_n_color = cpu_to_le32(mvm_sta->mac_id_n_color);