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iwlwifi: fix possible data overwrite in hcmd callback 

My commit 3598e1774c
"iwlwifi: fix enqueue hcmd race conditions" move hcmd callback after
command queue reclaim, to avoid call it with hcmd_lock. But since
queue read index was updated, cmd data can be overwritten. Fix problem
by calling callback before taking hcmd_lock and queue reclaim.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Stanislaw Gruszka 2011-04-20 16:02:58 +02:00 committed by John W. Linville
parent 9f2e731d1d
commit 2624e96ce1
1 changed files with 4 additions and 11 deletions
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15
drivers/net/wireless/iwlwifi/iwl-tx.c
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@ -621,9 +621,6 @@ void iwl_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
struct iwl_cmd_meta *meta;
struct iwl_tx_queue *txq = &priv->txq[priv->cmd_queue];
unsigned long flags;
void (*callback) (struct iwl_priv *priv, struct iwl_device_cmd *cmd,
struct iwl_rx_packet *pkt);
/* 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
@ -637,8 +634,6 @@ void iwl_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
return;
}
spin_lock_irqsave(&priv->hcmd_lock, flags);
cmd_index = get_cmd_index(&txq->q, index, huge);
cmd = txq->cmd[cmd_index];
meta = &txq->meta[cmd_index];
@ -648,13 +643,14 @@ void iwl_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
dma_unmap_len(meta, len),
PCI_DMA_BIDIRECTIONAL);
callback = NULL;
/* Input error checking is done when commands are added to queue. */
if (meta->flags & CMD_WANT_SKB) {
meta->source->reply_page = (unsigned long)rxb_addr(rxb);
rxb->page = NULL;
} else
callback = meta->callback;
} else if (meta->callback)
meta->callback(priv, cmd, pkt);
spin_lock_irqsave(&priv->hcmd_lock, flags);
iwl_hcmd_queue_reclaim(priv, txq_id, index, cmd_index);
@ -669,7 +665,4 @@ void iwl_tx_cmd_complete(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
meta->flags = 0;
spin_unlock_irqrestore(&priv->hcmd_lock, flags);
if (callback)
callback(priv, cmd, pkt);
}