From 81e63263aa3c5bfa64aa3206f4be3e59afc1c183 Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Thu, 28 Apr 2011 11:51:31 +0200 Subject: [PATCH] iwlegacy: fix enqueue hcmd race conditions We mark command as huge by using meta->flags from other (non huge) command, but flags can be possibly overridden, when non huge command is enqueued, what can lead to: WARNING: at lib/dma-debug.c:696 dma_debug_device_change+0x1a3/0x1f0() DMA-API: device driver has pending DMA allocations while released from device [count=1] To fix introduce additional CMD_MAPPED to mark command as mapped and serialize iwl_enqueue_hcmd() with iwl_tx_cmd_complete() using hcmd_lock. Serialization will also fix possible race conditions, because q->read_ptr, q->write_ptr are modified/used in parallel. Do not change callback, I did (and fixed) that mistake in iwlagn. Signed-off-by: Stanislaw Gruszka Signed-off-by: John W. Linville --- drivers/net/wireless/iwlegacy/iwl-dev.h | 1 + drivers/net/wireless/iwlegacy/iwl-tx.c | 54 ++++++++++++------------- 2 files changed, 26 insertions(+), 29 deletions(-) diff --git a/drivers/net/wireless/iwlegacy/iwl-dev.h b/drivers/net/wireless/iwlegacy/iwl-dev.h index 36c01aa3b7c2..df19d5c69e7f 100644 --- a/drivers/net/wireless/iwlegacy/iwl-dev.h +++ b/drivers/net/wireless/iwlegacy/iwl-dev.h @@ -290,6 +290,7 @@ enum { CMD_SIZE_HUGE = (1 << 0), CMD_ASYNC = (1 << 1), CMD_WANT_SKB = (1 << 2), + CMD_MAPPED = (1 << 3), }; #define DEF_CMD_PAYLOAD_SIZE 320 diff --git a/drivers/net/wireless/iwlegacy/iwl-tx.c b/drivers/net/wireless/iwlegacy/iwl-tx.c index a227773cb384..4fff995c6f3e 100644 --- a/drivers/net/wireless/iwlegacy/iwl-tx.c +++ b/drivers/net/wireless/iwlegacy/iwl-tx.c @@ -146,33 +146,32 @@ void iwl_legacy_cmd_queue_unmap(struct iwl_priv *priv) { struct iwl_tx_queue *txq = &priv->txq[priv->cmd_queue]; struct iwl_queue *q = &txq->q; - bool huge = false; int i; if (q->n_bd == 0) return; while (q->read_ptr != q->write_ptr) { - /* we have no way to tell if it is a huge cmd ATM */ i = iwl_legacy_get_cmd_index(q, q->read_ptr, 0); - if (txq->meta[i].flags & CMD_SIZE_HUGE) - huge = true; - else + if (txq->meta[i].flags & CMD_MAPPED) { pci_unmap_single(priv->pci_dev, dma_unmap_addr(&txq->meta[i], mapping), dma_unmap_len(&txq->meta[i], len), PCI_DMA_BIDIRECTIONAL); + txq->meta[i].flags = 0; + } q->read_ptr = iwl_legacy_queue_inc_wrap(q->read_ptr, q->n_bd); } - if (huge) { - i = q->n_window; + i = q->n_window; + if (txq->meta[i].flags & CMD_MAPPED) { pci_unmap_single(priv->pci_dev, dma_unmap_addr(&txq->meta[i], mapping), dma_unmap_len(&txq->meta[i], len), PCI_DMA_BIDIRECTIONAL); + txq->meta[i].flags = 0; } } EXPORT_SYMBOL(iwl_legacy_cmd_queue_unmap); @@ -467,29 +466,27 @@ int iwl_legacy_enqueue_hcmd(struct iwl_priv *priv, struct iwl_host_cmd *cmd) return -EIO; } - if (iwl_legacy_queue_space(q) < ((cmd->flags & CMD_ASYNC) ? 2 : 1)) { - IWL_ERR(priv, "No space in command queue\n"); - IWL_ERR(priv, "Restarting adapter due to queue full\n"); - queue_work(priv->workqueue, &priv->restart); - return -ENOSPC; - } - spin_lock_irqsave(&priv->hcmd_lock, flags); - /* If this is a huge cmd, mark the huge flag also on the meta.flags - * of the _original_ cmd. This is used for DMA mapping clean up. - */ - if (cmd->flags & CMD_SIZE_HUGE) { - idx = iwl_legacy_get_cmd_index(q, q->write_ptr, 0); - txq->meta[idx].flags = CMD_SIZE_HUGE; + if (iwl_legacy_queue_space(q) < ((cmd->flags & CMD_ASYNC) ? 2 : 1)) { + spin_unlock_irqrestore(&priv->hcmd_lock, flags); + + IWL_ERR(priv, "Restarting adapter due to command queue full\n"); + queue_work(priv->workqueue, &priv->restart); + return -ENOSPC; } idx = iwl_legacy_get_cmd_index(q, q->write_ptr, cmd->flags & CMD_SIZE_HUGE); out_cmd = txq->cmd[idx]; out_meta = &txq->meta[idx]; + if (WARN_ON(out_meta->flags & CMD_MAPPED)) { + spin_unlock_irqrestore(&priv->hcmd_lock, flags); + return -ENOSPC; + } + memset(out_meta, 0, sizeof(*out_meta)); /* re-initialize to NULL */ - out_meta->flags = cmd->flags; + out_meta->flags = cmd->flags | CMD_MAPPED; if (cmd->flags & CMD_WANT_SKB) out_meta->source = cmd; if (cmd->flags & CMD_ASYNC) @@ -610,6 +607,7 @@ iwl_legacy_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb) struct iwl_device_cmd *cmd; struct iwl_cmd_meta *meta; struct iwl_tx_queue *txq = &priv->txq[priv->cmd_queue]; + unsigned long flags; /* If a Tx command is being handled and it isn't in the actual * command queue then there a command routing bug has been introduced @@ -623,14 +621,6 @@ iwl_legacy_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb) return; } - /* If this is a huge cmd, clear the huge flag on the meta.flags - * of the _original_ cmd. So that iwl_legacy_cmd_queue_free won't unmap - * the DMA buffer for the scan (huge) command. - */ - if (huge) { - cmd_index = iwl_legacy_get_cmd_index(&txq->q, index, 0); - txq->meta[cmd_index].flags = 0; - } cmd_index = iwl_legacy_get_cmd_index(&txq->q, index, huge); cmd = txq->cmd[cmd_index]; meta = &txq->meta[cmd_index]; @@ -647,6 +637,8 @@ iwl_legacy_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb) } else if (meta->callback) meta->callback(priv, cmd, pkt); + spin_lock_irqsave(&priv->hcmd_lock, flags); + iwl_legacy_hcmd_queue_reclaim(priv, txq_id, index, cmd_index); if (!(meta->flags & CMD_ASYNC)) { @@ -655,6 +647,10 @@ iwl_legacy_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb) iwl_legacy_get_cmd_string(cmd->hdr.cmd)); wake_up_interruptible(&priv->wait_command_queue); } + + /* Mark as unmapped */ meta->flags = 0; + + spin_unlock_irqrestore(&priv->hcmd_lock, flags); } EXPORT_SYMBOL(iwl_legacy_tx_cmd_complete);