iwlwifi: fix the Transmit Frame Descriptor rings

egrumbach · gregkh · commit 77bcff9d8249 · 2012-06-22T11:37:16.000-07:00
commit ebed633 upstream. The logic that allows to have a short TFD queue was completely wrong. We do maintain 256 Transmit Frame Descriptors, but they point to recycled buffers. We used to attach and de-attach different TFDs for the same buffer and it worked since they pointed to the same buffer. Also zero the number of BDs after unmapping a TFD. This seems not necessary since we don't reclaim the same TFD twice, but I like housekeeping. This patch solves this warning: [ 6427.079855] WARNING: at lib/dma-debug.c:866 check_unmap+0x727/0x7a0() [ 6427.079859] Hardware name: Latitude E6410 [ 6427.079865] iwlwifi 0000:02:00.0: DMA-API: device driver tries to free DMA memory it has not allocated [device address=0x00000000296d393c] [size=8 bytes] [ 6427.079870] Modules linked in: ... [ 6427.079950] Pid: 6613, comm: ifconfig Tainted: G O 3.3.3 #5 [ 6427.079954] Call Trace: [ 6427.079963] [<c10337a2>] warn_slowpath_common+0x72/0xa0 [ 6427.079982] [<c1033873>] warn_slowpath_fmt+0x33/0x40 [ 6427.079988] [<c12dcb77>] check_unmap+0x727/0x7a0 [ 6427.079995] [<c12dcdaa>] debug_dma_unmap_page+0x5a/0x80 [ 6427.080024] [<fe2312ac>] iwlagn_unmap_tfd+0x12c/0x180 [iwlwifi] [ 6427.080048] [<fe231349>] iwlagn_txq_free_tfd+0x49/0xb0 [iwlwifi] [ 6427.080071] [<fe228e37>] iwl_tx_queue_unmap+0x67/0x90 [iwlwifi] [ 6427.080095] [<fe22d221>] iwl_trans_pcie_stop_device+0x341/0x7b0 [iwlwifi] [ 6427.080113] [<fe204b0e>] iwl_down+0x17e/0x260 [iwlwifi] [ 6427.080132] [<fe20efec>] iwlagn_mac_stop+0x6c/0xf0 [iwlwifi] [ 6427.080168] [<fd8480ce>] ieee80211_stop_device+0x5e/0x190 [mac80211] [ 6427.080198] [<fd833208>] ieee80211_do_stop+0x288/0x620 [mac80211] [ 6427.080243] [<fd8335b7>] ieee80211_stop+0x17/0x20 [mac80211] [ 6427.080250] [<c148dac1>] __dev_close_many+0x81/0xd0 [ 6427.080270] [<c148db3d>] __dev_close+0x2d/0x50 [ 6427.080276] [<c148d152>] __dev_change_flags+0x82/0x150 [ 6427.080282] [<c148e3e3>] dev_change_flags+0x23/0x60 [ 6427.080289] [<c14f6320>] devinet_ioctl+0x6a0/0x770 [ 6427.080296] [<c14f8705>] inet_ioctl+0x95/0xb0 [ 6427.080304] [<c147a0f0>] sock_ioctl+0x70/0x270 Reported-by: Antonio Quartulli <ordex@autistici.org> Tested-by: Antonio Quartulli <ordex@autistici.org> Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Reviewed-by: Wey-Yi W Guy <wey-yi.w.guy@intel.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-int.h b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-int.h
@@ -342,7 +342,7 @@ void iwl_trans_pcie_tx_agg_setup(struct iwl_trans *trans,
 				 enum iwl_rxon_context_id ctx,
 				 int sta_id, int tid, int frame_limit, u16 ssn);
 void iwlagn_txq_free_tfd(struct iwl_trans *trans, struct iwl_tx_queue *txq,
-	int index, enum dma_data_direction dma_dir);
+			 enum dma_data_direction dma_dir);
 int iwl_tx_queue_reclaim(struct iwl_trans *trans, int txq_id, int index,
 			 struct sk_buff_head *skbs);
 int iwl_queue_space(const struct iwl_queue *q);
diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-tx.c b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-tx.c
@@ -237,40 +237,46 @@ static void iwlagn_unmap_tfd(struct iwl_trans *trans, struct iwl_cmd_meta *meta,
 	for (i = 1; i < num_tbs; i++)
 		dma_unmap_single(trans->dev, iwl_tfd_tb_get_addr(tfd, i),
 				iwl_tfd_tb_get_len(tfd, i), dma_dir);
+
+	tfd->num_tbs = 0;
 }
 
 /**
  * iwlagn_txq_free_tfd - Free all chunks referenced by TFD [txq->q.read_ptr]
  * @trans - transport private data
  * @txq - tx queue
- * @index - the index of the TFD to be freed
- *@dma_dir - the direction of the DMA mapping
+ * @dma_dir - the direction of the DMA mapping
  *
  * Does NOT advance any TFD circular buffer read/write indexes
  * Does NOT free the TFD itself (which is within circular buffer)
  */
 void iwlagn_txq_free_tfd(struct iwl_trans *trans, struct iwl_tx_queue *txq,
-	int index, enum dma_data_direction dma_dir)
+			 enum dma_data_direction dma_dir)
 {
 	struct iwl_tfd *tfd_tmp = txq->tfds;
 
+	/* rd_ptr is bounded by n_bd and idx is bounded by n_window */
+	int rd_ptr = txq->q.read_ptr;
+	int idx = get_cmd_index(&txq->q, rd_ptr);
+
 	lockdep_assert_held(&txq->lock);
 
-	iwlagn_unmap_tfd(trans, &txq->meta[index], &tfd_tmp[index], dma_dir);
+	/* We have only q->n_window txq->entries, but we use q->n_bd tfds */
+	iwlagn_unmap_tfd(trans, &txq->meta[idx], &tfd_tmp[rd_ptr], dma_dir);
 
 	/* free SKB */
 	if (txq->skbs) {
 		struct sk_buff *skb;
 
-		skb = txq->skbs[index];
+		skb = txq->skbs[idx];
 
 		/* Can be called from irqs-disabled context
 		 * If skb is not NULL, it means that the whole queue is being
 		 * freed and that the queue is not empty - free the skb
 		 */
 		if (skb) {
 			iwl_op_mode_free_skb(trans->op_mode, skb);
-			txq->skbs[index] = NULL;
+			txq->skbs[idx] = NULL;
 		}
 	}
 }
@@ -1100,7 +1106,7 @@ int iwl_tx_queue_reclaim(struct iwl_trans *trans, int txq_id, int index,
 
 		iwlagn_txq_inval_byte_cnt_tbl(trans, txq);
 
-		iwlagn_txq_free_tfd(trans, txq, txq->q.read_ptr, DMA_TO_DEVICE);
+		iwlagn_txq_free_tfd(trans, txq, DMA_TO_DEVICE);
 		freed++;
 	}
 	return freed;
diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c b/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c
@@ -430,9 +430,7 @@ static void iwl_tx_queue_unmap(struct iwl_trans *trans, int txq_id)
 
 	spin_lock_bh(&txq->lock);
 	while (q->write_ptr != q->read_ptr) {
-		/* The read_ptr needs to bound by q->n_window */
-		iwlagn_txq_free_tfd(trans, txq, get_cmd_index(q, q->read_ptr),
-				    dma_dir);
+		iwlagn_txq_free_tfd(trans, txq, dma_dir);
 		q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd);
 	}
 	spin_unlock_bh(&txq->lock);
