Re: [rt2x00-users] [PATCH 6/7] rt2x00: Queue index locks don't have to disable IRQs.

[Gertjan van Wingerde <gwingerde@gmail.com>]

On 05/18/11 20:25, Ivo van Doorn wrote:
> From: Gertjan van Wingerde <gwingerde@gmail.com>
> 
> The queue index locks are no longer used in interrupt context due to the
> introduction of tasklets and workqueues. Therefore we can use a lighter
> variant of the spinlocks.
> 
> Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
> Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>

John, as noted in another email on the mailing list, this patch seems to introduce
a problem on USB devices, which escaped my testing for some reason.

Hence, please do not apply this patch to wireless-next.

Patch 7 of the series does not depend on this patch, so that one can still be applied.

> ---
>  drivers/net/wireless/rt2x00/rt2x00debug.c |    5 ++---
>  drivers/net/wireless/rt2x00/rt2x00queue.c |   20 ++++++++------------
>  2 files changed, 10 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/net/wireless/rt2x00/rt2x00debug.c b/drivers/net/wireless/rt2x00/rt2x00debug.c
> index 78787fc..8e417de 100644
> --- a/drivers/net/wireless/rt2x00/rt2x00debug.c
> +++ b/drivers/net/wireless/rt2x00/rt2x00debug.c
> @@ -327,7 +327,6 @@ static ssize_t rt2x00debug_read_queue_stats(struct file *file,
>  {
>  	struct rt2x00debug_intf *intf = file->private_data;
>  	struct data_queue *queue;
> -	unsigned long irqflags;
>  	unsigned int lines = 1 + intf->rt2x00dev->data_queues;
>  	size_t size;
>  	char *data;
> @@ -344,7 +343,7 @@ static ssize_t rt2x00debug_read_queue_stats(struct file *file,
>  	    sprintf(data, "qid\tflags\t\tcount\tlimit\tlength\tindex\tdma done\tdone\n");
>  
>  	queue_for_each(intf->rt2x00dev, queue) {
> -		spin_lock_irqsave(&queue->index_lock, irqflags);
> +		spin_lock_bh(&queue->index_lock);
>  
>  		temp += sprintf(temp, "%d\t0x%.8x\t%d\t%d\t%d\t%d\t%d\t\t%d\n",
>  				queue->qid, (unsigned int)queue->flags,
> @@ -353,7 +352,7 @@ static ssize_t rt2x00debug_read_queue_stats(struct file *file,
>  				queue->index[Q_INDEX_DMA_DONE],
>  				queue->index[Q_INDEX_DONE]);
>  
> -		spin_unlock_irqrestore(&queue->index_lock, irqflags);
> +		spin_unlock_bh(&queue->index_lock);
>  	}
>  
>  	size = strlen(data);
> diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
> index f1e1381..e2e1bf6 100644
> --- a/drivers/net/wireless/rt2x00/rt2x00queue.c
> +++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
> @@ -735,7 +735,6 @@ bool rt2x00queue_for_each_entry(struct data_queue *queue,
>  				bool (*fn)(struct queue_entry *entry,
>  					   void *data))
>  {
> -	unsigned long irqflags;
>  	unsigned int index_start;
>  	unsigned int index_end;
>  	unsigned int i;
> @@ -753,10 +752,10 @@ bool rt2x00queue_for_each_entry(struct data_queue *queue,
>  	 * it should not be kicked during this run, since it
>  	 * is part of another TX operation.
>  	 */
> -	spin_lock_irqsave(&queue->index_lock, irqflags);
> +	spin_lock_bh(&queue->index_lock);
>  	index_start = queue->index[start];
>  	index_end = queue->index[end];
> -	spin_unlock_irqrestore(&queue->index_lock, irqflags);
> +	spin_unlock_bh(&queue->index_lock);
>  
>  	/*
>  	 * Start from the TX done pointer, this guarentees that we will
> @@ -787,7 +786,6 @@ struct queue_entry *rt2x00queue_get_entry(struct data_queue *queue,
>  					  enum queue_index index)
>  {
>  	struct queue_entry *entry;
> -	unsigned long irqflags;
>  
>  	if (unlikely(index >= Q_INDEX_MAX)) {
>  		ERROR(queue->rt2x00dev,
> @@ -795,11 +793,11 @@ struct queue_entry *rt2x00queue_get_entry(struct data_queue *queue,
>  		return NULL;
>  	}
>  
> -	spin_lock_irqsave(&queue->index_lock, irqflags);
> +	spin_lock_bh(&queue->index_lock);
>  
>  	entry = &queue->entries[queue->index[index]];
>  
> -	spin_unlock_irqrestore(&queue->index_lock, irqflags);
> +	spin_unlock_bh(&queue->index_lock);
>  
>  	return entry;
>  }
> @@ -808,7 +806,6 @@ EXPORT_SYMBOL_GPL(rt2x00queue_get_entry);
>  void rt2x00queue_index_inc(struct queue_entry *entry, enum queue_index index)
>  {
>  	struct data_queue *queue = entry->queue;
> -	unsigned long irqflags;
>  
>  	if (unlikely(index >= Q_INDEX_MAX)) {
>  		ERROR(queue->rt2x00dev,
> @@ -816,7 +813,7 @@ void rt2x00queue_index_inc(struct queue_entry *entry, enum queue_index index)
>  		return;
>  	}
>  
> -	spin_lock_irqsave(&queue->index_lock, irqflags);
> +	spin_lock_bh(&queue->index_lock);
>  
>  	queue->index[index]++;
>  	if (queue->index[index] >= queue->limit)
> @@ -831,7 +828,7 @@ void rt2x00queue_index_inc(struct queue_entry *entry, enum queue_index index)
>  		queue->count++;
>  	}
>  
> -	spin_unlock_irqrestore(&queue->index_lock, irqflags);
> +	spin_unlock_bh(&queue->index_lock);
>  }
>  
>  void rt2x00queue_pause_queue(struct data_queue *queue)
> @@ -1031,10 +1028,9 @@ EXPORT_SYMBOL_GPL(rt2x00queue_flush_queues);
>  
>  static void rt2x00queue_reset(struct data_queue *queue)
>  {
> -	unsigned long irqflags;
>  	unsigned int i;
>  
> -	spin_lock_irqsave(&queue->index_lock, irqflags);
> +	spin_lock_bh(&queue->index_lock);
>  
>  	queue->count = 0;
>  	queue->length = 0;
> @@ -1042,7 +1038,7 @@ static void rt2x00queue_reset(struct data_queue *queue)
>  	for (i = 0; i < Q_INDEX_MAX; i++)
>  		queue->index[i] = 0;
>  
> -	spin_unlock_irqrestore(&queue->index_lock, irqflags);
> +	spin_unlock_bh(&queue->index_lock);
>  }
>  
>  void rt2x00queue_init_queues(struct rt2x00_dev *rt2x00dev)


-- 
---
Gertjan