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Subject[ 58/61] iwlwifi: fix the Transmit Frame Descriptor rings
3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

commit ebed633c61c023e5d1aa4ed159cd67406e9e37c2 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>

---
drivers/net/wireless/iwlwifi/iwl-trans-pcie-int.h | 2 +-
drivers/net/wireless/iwlwifi/iwl-trans-pcie-tx.c | 20 +++++++++++++-------
drivers/net/wireless/iwlwifi/iwl-trans-pcie.c | 4 +---
3 files changed, 15 insertions(+), 11 deletions(-)

--- 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
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);
--- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-tx.c
@@ -237,32 +237,38 @@ static void iwlagn_unmap_tfd(struct iwl_
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
@@ -270,7 +276,7 @@ void iwlagn_txq_free_tfd(struct iwl_tran
*/
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_tran

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;
--- 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 iw

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);



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