2011-05-18 18:26:49

by Ivo Van Doorn

[permalink] [raw]
Subject: [PATCH 6/7] rt2x00: Queue index locks don't have to disable IRQs.

From: Gertjan van Wingerde <[email protected]>

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 <[email protected]>
Signed-off-by: Ivo van Doorn <[email protected]>
---
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)
--
1.7.2.3



2011-05-18 20:54:53

by Gertjan van Wingerde

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

On 05/18/11 20:25, Ivo van Doorn wrote:
> From: Gertjan van Wingerde <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Ivo van Doorn <[email protected]>

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