From 0a2b97bebd6495c1c9bb09aad0775f8d6a993881 Mon Sep 17 00:00:00 2001 From: Gertjan van Wingerde Date: Fri, 23 Sep 2011 09:20:00 -0700 Subject: [PATCH] rt2x00: Serialize TX operations on a queue. BugLink: https://bugs.launchpad.net/bugs/855239 The rt2x00 driver gets frequent occurrences of the following error message when operating under load: phy0 -> rt2x00queue_write_tx_frame: Error - Arrived at non-free entry in the non-full queue 2. This is caused by simultaneous attempts from mac80211 to send a frame via rt2x00, which are not properly serialized inside rt2x00queue_write_tx_frame, causing the second frame to fail sending with the above mentioned error message. Fix this by introducing a per-queue spinlock to serialize the TX operations on that queue. Reported-by: Andreas Hartmann Signed-off-by: Gertjan van Wingerde Acked-by: Helmut Schaa Signed-off-by: Ivo van Doorn Signed-off-by: John W. Linville (backported from upstream commit 77a861c405da75d81e9e6e32c50eb7f9777777e8) Signed-off-by: Leann Ogasawara Acked-by: Seth Forshee Signed-off-by: Tim Gardner --- drivers/net/wireless/rt2x00/rt2x00queue.c | 26 ++++++++++++++++++++------ drivers/net/wireless/rt2x00/rt2x00queue.h | 2 ++ 2 files changed, 22 insertions(+), 6 deletions(-) diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c index ca82b3a..b1a9078 100644 --- a/drivers/net/wireless/rt2x00/rt2x00queue.c +++ b/drivers/net/wireless/rt2x00/rt2x00queue.c @@ -478,13 +478,22 @@ int rt2x00queue_write_tx_frame(struct data_queue *queue, struct sk_buff *skb, bool local) { struct ieee80211_tx_info *tx_info; - struct queue_entry *entry = rt2x00queue_get_entry(queue, Q_INDEX); + struct queue_entry *entry; struct txentry_desc txdesc; struct skb_frame_desc *skbdesc; u8 rate_idx, rate_flags; + int ret = 0; - if (unlikely(rt2x00queue_full(queue))) - return -ENOBUFS; + spin_lock(&queue->tx_lock); + + entry = rt2x00queue_get_entry(queue, Q_INDEX); + + if (unlikely(rt2x00queue_full(queue))) { + ERROR(queue->rt2x00dev, + "Dropping frame due to full tx queue %d.\n", queue->qid); + ret = -ENOBUFS; + goto out; + } if (unlikely(test_and_set_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags))) { @@ -492,7 +501,8 @@ int rt2x00queue_write_tx_frame(struct data_queue *queue, struct sk_buff *skb, "Arrived at non-free entry in the non-full queue %d.\n" "Please file bug report to %s.\n", queue->qid, DRV_PROJECT); - return -EINVAL; + ret = -EINVAL; + goto out; } /* @@ -554,7 +564,8 @@ int rt2x00queue_write_tx_frame(struct data_queue *queue, struct sk_buff *skb, if (unlikely(rt2x00queue_write_tx_data(entry, &txdesc))) { clear_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags); entry->skb = NULL; - return -EIO; + ret = -EIO; + goto out; } set_bit(ENTRY_DATA_PENDING, &entry->flags); @@ -563,7 +574,9 @@ int rt2x00queue_write_tx_frame(struct data_queue *queue, struct sk_buff *skb, rt2x00queue_write_tx_descriptor(entry, &txdesc); rt2x00queue_kick_tx_queue(queue, &txdesc); - return 0; +out: + spin_unlock(&queue->tx_lock); + return ret; } int rt2x00queue_update_beacon(struct rt2x00_dev *rt2x00dev, @@ -1099,6 +1112,7 @@ static void rt2x00queue_init(struct rt2x00_dev *rt2x00dev, struct data_queue *queue, enum data_queue_qid qid) { mutex_init(&queue->status_lock); + spin_lock_init(&queue->tx_lock); spin_lock_init(&queue->index_lock); queue->rt2x00dev = rt2x00dev; diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.h b/drivers/net/wireless/rt2x00/rt2x00queue.h index fab8e26..d94ab20 100644 --- a/drivers/net/wireless/rt2x00/rt2x00queue.h +++ b/drivers/net/wireless/rt2x00/rt2x00queue.h @@ -422,6 +422,7 @@ enum data_queue_flags { * @flags: Entry flags, see &enum queue_entry_flags. * @status_lock: The mutex for protecting the start/stop/flush * handling on this queue. + * @tx_lock: Spinlock to serialize tx operations on this queue. * @index_lock: Spinlock to protect index handling. Whenever @index, @index_done or * @index_crypt needs to be changed this lock should be grabbed to prevent * index corruption due to concurrency. @@ -448,6 +449,7 @@ struct data_queue { unsigned long flags; struct mutex status_lock; + spinlock_t tx_lock; spinlock_t index_lock; unsigned int count; -- 1.7.10.4