Re: [PATCH] p54: Fix regression in 2.6.31-rcX since commit a1091aa - sleeping function called from invalid context
From: Bjarke Istrup Pedersen
Date: Mon Jul 06 2009 - 16:26:24 EST
2009/7/6 David Miller <davem@xxxxxxxxxxxxx>:
> From: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
> Date: Mon, 06 Jul 2009 14:43:45 -0500
>
>> I'm available for testing.
>
> I just committed the following to my net-2.6 tree, give
> it a spin:
>
> From 0ca1b08eba627b4245efd0f71b55a062bf163777 Mon Sep 17 00:00:00 2001
> From: David S. Miller <davem@xxxxxxxxxxxxx>
> Date: Mon, 6 Jul 2009 12:49:18 -0700
> Subject: [PATCH] Revert "p54: Use SKB list handling helpers instead of by-hand code."
>
> This reverts commit a1091aae19b1d9c85d91c86915a611387f67a26b.
> ---
> drivers/net/wireless/p54/p54common.c | 46 ++++++++++++++++++++--------------
> 1 files changed, 27 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/net/wireless/p54/p54common.c b/drivers/net/wireless/p54/p54common.c
> index b618bd1..48d81d9 100644
> --- a/drivers/net/wireless/p54/p54common.c
> +++ b/drivers/net/wireless/p54/p54common.c
> @@ -823,30 +823,30 @@ void p54_free_skb(struct ieee80211_hw *dev, struct sk_buff *skb)
> struct p54_tx_info *range;
> unsigned long flags;
>
> - if (unlikely(!skb || !dev || skb_queue_empty(&priv->tx_queue)))
> + if (unlikely(!skb || !dev || !skb_queue_len(&priv->tx_queue)))
> return;
>
> - /* There used to be a check here to see if the SKB was on the
> - * TX queue or not. This can never happen because all SKBs we
> - * see here successfully went through p54_assign_address()
> - * which means the SKB is on the ->tx_queue.
> + /*
> + * don't try to free an already unlinked skb
> */
> + if (unlikely((!skb->next) || (!skb->prev)))
> + return;
>
> spin_lock_irqsave(&priv->tx_queue.lock, flags);
> info = IEEE80211_SKB_CB(skb);
> range = (void *)info->rate_driver_data;
> - if (!skb_queue_is_first(&priv->tx_queue, skb)) {
> + if (skb->prev != (struct sk_buff *)&priv->tx_queue) {
> struct ieee80211_tx_info *ni;
> struct p54_tx_info *mr;
>
> - ni = IEEE80211_SKB_CB(skb_queue_prev(&priv->tx_queue, skb));
> + ni = IEEE80211_SKB_CB(skb->prev);
> mr = (struct p54_tx_info *)ni->rate_driver_data;
> }
> - if (!skb_queue_is_last(&priv->tx_queue, skb)) {
> + if (skb->next != (struct sk_buff *)&priv->tx_queue) {
> struct ieee80211_tx_info *ni;
> struct p54_tx_info *mr;
>
> - ni = IEEE80211_SKB_CB(skb_queue_next(&priv->tx_queue, skb));
> + ni = IEEE80211_SKB_CB(skb->next);
> mr = (struct p54_tx_info *)ni->rate_driver_data;
> }
> __skb_unlink(skb, &priv->tx_queue);
> @@ -864,13 +864,15 @@ static struct sk_buff *p54_find_tx_entry(struct ieee80211_hw *dev,
> unsigned long flags;
>
> spin_lock_irqsave(&priv->tx_queue.lock, flags);
> - skb_queue_walk(&priv->tx_queue, entry) {
> + entry = priv->tx_queue.next;
> + while (entry != (struct sk_buff *)&priv->tx_queue) {
> struct p54_hdr *hdr = (struct p54_hdr *) entry->data;
>
> if (hdr->req_id == req_id) {
> spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
> return entry;
> }
> + entry = entry->next;
> }
> spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
> return NULL;
> @@ -888,22 +890,24 @@ static void p54_rx_frame_sent(struct ieee80211_hw *dev, struct sk_buff *skb)
> int count, idx;
>
> spin_lock_irqsave(&priv->tx_queue.lock, flags);
> - skb_queue_walk(&priv->tx_queue, entry) {
> + entry = (struct sk_buff *) priv->tx_queue.next;
> + while (entry != (struct sk_buff *)&priv->tx_queue) {
> struct ieee80211_tx_info *info = IEEE80211_SKB_CB(entry);
> struct p54_hdr *entry_hdr;
> struct p54_tx_data *entry_data;
> unsigned int pad = 0, frame_len;
>
> range = (void *)info->rate_driver_data;
> - if (range->start_addr != addr)
> + if (range->start_addr != addr) {
> + entry = entry->next;
> continue;
> + }
>
> - if (!skb_queue_is_last(&priv->tx_queue, entry)) {
> + if (entry->next != (struct sk_buff *)&priv->tx_queue) {
> struct ieee80211_tx_info *ni;
> struct p54_tx_info *mr;
>
> - ni = IEEE80211_SKB_CB(skb_queue_next(&priv->tx_queue,
> - entry));
> + ni = IEEE80211_SKB_CB(entry->next);
> mr = (struct p54_tx_info *)ni->rate_driver_data;
> }
>
> @@ -1164,21 +1168,23 @@ static int p54_assign_address(struct ieee80211_hw *dev, struct sk_buff *skb,
> }
> }
>
> - skb_queue_walk(&priv->tx_queue, entry) {
> + entry = priv->tx_queue.next;
> + while (left--) {
> u32 hole_size;
> info = IEEE80211_SKB_CB(entry);
> range = (void *)info->rate_driver_data;
> hole_size = range->start_addr - last_addr;
> if (!target_skb && hole_size >= len) {
> - target_skb = skb_queue_prev(&priv->tx_queue, entry);
> + target_skb = entry->prev;
> hole_size -= len;
> target_addr = last_addr;
> }
> largest_hole = max(largest_hole, hole_size);
> last_addr = range->end_addr;
> + entry = entry->next;
> }
> if (!target_skb && priv->rx_end - last_addr >= len) {
> - target_skb = skb_peek_tail(&priv->tx_queue);
> + target_skb = priv->tx_queue.prev;
> largest_hole = max(largest_hole, priv->rx_end - last_addr - len);
> if (!skb_queue_empty(&priv->tx_queue)) {
> info = IEEE80211_SKB_CB(target_skb);
> @@ -2084,6 +2090,7 @@ out:
> static void p54_stop(struct ieee80211_hw *dev)
> {
> struct p54_common *priv = dev->priv;
> + struct sk_buff *skb;
>
> mutex_lock(&priv->conf_mutex);
> priv->mode = NL80211_IFTYPE_UNSPECIFIED;
> @@ -2098,7 +2105,8 @@ static void p54_stop(struct ieee80211_hw *dev)
> p54_tx_cancel(dev, priv->cached_beacon);
>
> priv->stop(dev);
> - skb_queue_purge(&priv->tx_queue);
> + while ((skb = skb_dequeue(&priv->tx_queue)))
> + kfree_skb(skb);
> priv->cached_beacon = NULL;
> priv->tsf_high32 = priv->tsf_low32 = 0;
> mutex_unlock(&priv->conf_mutex);
> --
> 1.6.3.3
>
> --
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I can confirm that the patch fixes the problem with my PCMCIA card :-)
Best regards,
Bjarke Istrup Pedersen
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