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>

1 files changed, 35 insertions, 3 deletions

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);