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staging/most, dim2: convert dim2_tasklet to threaded irq

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Tasklets have long been deprecated as being too heavy on the system
by running in irq context - and this is not a performance critical
path. If a higher priority process wants to run, it must wait for
the tasklet to finish before doing so. A more suitable equivalent
is to converted to threaded irq instead and service channels in
regular task context.

Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Link: https://lore.kernel.org/r/20220411151620.129178-2-dave@stgolabs.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Davidlohr Bueso 2022-04-11 08:16:15 -07:00 committed by Greg Kroah-Hartman
parent 88d33bb879
commit 5fb6bc718c
1 changed files with 9 additions and 20 deletions
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29
drivers/staging/most/dim2/dim2.c
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@ -45,9 +45,6 @@ MODULE_PARM_DESC(fcnt, "Num of frames per sub-buffer for sync channels as a powe
static DEFINE_SPINLOCK(dim_lock);
static void dim2_tasklet_fn(unsigned long data);
static DECLARE_TASKLET_OLD(dim2_tasklet, dim2_tasklet_fn);
/**
* struct hdm_channel - private structure to keep channel specific data
* @name: channel name
@ -361,15 +358,9 @@ static irqreturn_t dim2_mlb_isr(int irq, void *_dev)
return IRQ_HANDLED;
}
/**
* dim2_tasklet_fn - tasklet function
* @data: private data
*
* Service each initialized channel, if needed
*/
static void dim2_tasklet_fn(unsigned long data)
static irqreturn_t dim2_task_irq(int irq, void *_dev)
{
struct dim2_hdm *dev = (struct dim2_hdm *)data;
struct dim2_hdm *dev = _dev;
unsigned long flags;
int ch_idx;
@ -385,6 +376,8 @@ static void dim2_tasklet_fn(unsigned long data)
while (!try_start_dim_transfer(dev->hch + ch_idx))
continue;
}
return IRQ_HANDLED;
}
/**
@ -392,8 +385,8 @@ static void dim2_tasklet_fn(unsigned long data)
* @irq: irq number
* @_dev: private data
*
* Acknowledge the interrupt and schedule a tasklet to service channels.
* Return IRQ_HANDLED.
* Acknowledge the interrupt and service each initialized channel,
* if needed, in task context.
*/
static irqreturn_t dim2_ahb_isr(int irq, void *_dev)
{
@ -405,9 +398,7 @@ static irqreturn_t dim2_ahb_isr(int irq, void *_dev)
dim_service_ahb_int_irq(get_active_channels(dev, buffer));
spin_unlock_irqrestore(&dim_lock, flags);
dim2_tasklet.data = (unsigned long)dev;
tasklet_schedule(&dim2_tasklet);
return IRQ_HANDLED;
return IRQ_WAKE_THREAD;
}
/**
@ -654,14 +645,12 @@ static int poison_channel(struct most_interface *most_iface, int ch_idx)
if (!hdm_ch->is_initialized)
return -EPERM;
tasklet_disable(&dim2_tasklet);
spin_lock_irqsave(&dim_lock, flags);
hal_ret = dim_destroy_channel(&hdm_ch->ch);
hdm_ch->is_initialized = false;
if (ch_idx == dev->atx_idx)
dev->atx_idx = -1;
spin_unlock_irqrestore(&dim_lock, flags);
tasklet_enable(&dim2_tasklet);
if (hal_ret != DIM_NO_ERROR) {
pr_err("HAL Failed to close channel %s\n", hdm_ch->name);
ret = -EFAULT;
@ -821,8 +810,8 @@ static int dim2_probe(struct platform_device *pdev)
goto err_shutdown_dim;
}
ret = devm_request_irq(&pdev->dev, irq, dim2_ahb_isr, 0,
"dim2_ahb0_int", dev);
ret = devm_request_threaded_irq(&pdev->dev, irq, dim2_ahb_isr,
dim2_task_irq, 0, "dim2_ahb0_int", dev);
if (ret) {
dev_err(&pdev->dev, "failed to request ahb0_int irq %d\n", irq);
goto err_shutdown_dim;