From 8e3bad65a59915f2ddc40f62a180ad81695d8440 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 17 Nov 2008 10:59:59 +0100 Subject: mac80211: remove ieee80211_notify_mac Before ieee80211_notify_mac() was added, it was presented with the use case of using it to tell mac80211 that the association may have been lost because the firmware crashed/reset. Since then, it has also been used by iwlwifi to (slightly) speed up re-association after resume, a workaround around the fact that mac80211 has no suspend/resume handling yet. It is also not used by any other drivers, so clearly it cannot be necessary for "good enough" suspend/resume. Unfortunately, the callback suffers from a severe problem: It only works for station mode. If suspend/resume happens while in IBSS or any other mode (but station), then the callback is pointless. Recently, it has created a number of locking issues, first because it required rtnl locking rather than RCU due to calling sleeping functions within the critical section, and now because it's called by iwlwifi from the mac80211 workqueue that may not use the rtnl because it is flushed under rtnl. (cf. http://bugzilla.kernel.org/show_bug.cgi?id=12046) I think, therefore, that we should take a step back, remove it entirely for now and add the small feature it provided properly. For suspend and resume we will need to introduce new hooks, and for the case where the firmware was reset the driver will probably simply just pretend it has done a suspend/resume cycle to get mac80211 to reprogram the hardware completely, not just try to connect to the current AP again in station mode. When doing so, we will need to take into account locking issues and possibly defer to schedule_work from within mac80211 for the resume operation, while the suspend operation must be done directly. Proper suspend/resume should also not necessarily try to reconnect to the current AP, the time spent in suspend may have been short enough to not be disconnected from the AP, mac80211 will detect that the AP went out of range quickly if it did, and if the association is lost then the AP will disassoc as soon as a data frame is sent. We might also take into account WWOL then, and have mac80211 program the hardware into such a mode where it is available and requested. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- drivers/net/wireless/iwlwifi/iwl-agn.c | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/net/wireless/iwlwifi/iwl-agn.c') diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c index 8d690a0eb1a..6751bb2b8ae 100644 --- a/drivers/net/wireless/iwlwifi/iwl-agn.c +++ b/drivers/net/wireless/iwlwifi/iwl-agn.c @@ -2341,7 +2341,6 @@ static void iwl_bg_alive_start(struct work_struct *data) mutex_lock(&priv->mutex); iwl_alive_start(priv); mutex_unlock(&priv->mutex); - ieee80211_notify_mac(priv->hw, IEEE80211_NOTIFY_RE_ASSOC); } static void iwl4965_bg_rf_kill(struct work_struct *work) -- cgit v1.2.3 From 4018517a1a69a85c3d61b20fa02f187b80773137 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 18 Nov 2008 01:47:21 +0100 Subject: iwlagn: fix RX skb alignment So I dug deeper into the DMA problems I had with iwlagn and a kind soul helped me in that he said something about pci-e alignment and mentioned the iwl_rx_allocate function to check for crossing 4KB boundaries. Since there's 8KB A-MPDU support, crossing 4k boundaries didn't seem like something the device would fail with, but when I looked into the function for a minute anyway I stumbled over this little gem: BUG_ON(rxb->dma_addr & (~DMA_BIT_MASK(36) & 0xff)); Clearly, that is a totally bogus check, one would hope the compiler removes it entirely. (Think about it) After fixing it, I obviously ran into it, nothing guarantees the alignment the way you want it, because of the way skbs and their headroom are allocated. I won't explain that here nor double-check that I'm right, that goes beyond what most of the CC'ed people care about. So then I came up with the patch below, and so far my system has survived minutes with 64K pages, when it would previously fail in seconds. And I haven't seen a single instance of the TX bug either. But when you see the patch it'll be pretty obvious to you why. This should fix the following reported kernel bugs: http://bugzilla.kernel.org/show_bug.cgi?id=11596 http://bugzilla.kernel.org/show_bug.cgi?id=11393 http://bugzilla.kernel.org/show_bug.cgi?id=11983 I haven't checked if there are any elsewhere, but I suppose RHBZ will have a few instances too... I'd like to ask anyone who is CC'ed (those are people I know ran into the bug) to try this patch. I am convinced that this patch is correct in spirit, but I haven't understood why, for example, there are so many unmap calls. I'm not entirely convinced that this is the only bug leading to the TX reply errors. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- drivers/net/wireless/iwlwifi/iwl-agn.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/net/wireless/iwlwifi/iwl-agn.c') diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c index 6751bb2b8ae..444c5cc05f0 100644 --- a/drivers/net/wireless/iwlwifi/iwl-agn.c +++ b/drivers/net/wireless/iwlwifi/iwl-agn.c @@ -1384,7 +1384,7 @@ void iwl_rx_handle(struct iwl_priv *priv) rxq->queue[i] = NULL; - pci_dma_sync_single_for_cpu(priv->pci_dev, rxb->dma_addr, + pci_dma_sync_single_for_cpu(priv->pci_dev, rxb->aligned_dma_addr, priv->hw_params.rx_buf_size, PCI_DMA_FROMDEVICE); pkt = (struct iwl_rx_packet *)rxb->skb->data; @@ -1436,8 +1436,8 @@ void iwl_rx_handle(struct iwl_priv *priv) rxb->skb = NULL; } - pci_unmap_single(priv->pci_dev, rxb->dma_addr, - priv->hw_params.rx_buf_size, + pci_unmap_single(priv->pci_dev, rxb->real_dma_addr, + priv->hw_params.rx_buf_size + 256, PCI_DMA_FROMDEVICE); spin_lock_irqsave(&rxq->lock, flags); list_add_tail(&rxb->list, &priv->rxq.rx_used); -- cgit v1.2.3