Messages in this thread Patch in this message | | | From | Davidlohr Bueso <> | Subject | [PATCH] mailbox: bcm: Replace tasklet with threaded irq | Date | Thu, 14 Jan 2021 16:21:34 -0800 |
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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.
Use a more suitable alternative such as threaded irqs and do the async work in process context.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de> --- drivers/mailbox/bcm-pdc-mailbox.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-)
diff --git a/drivers/mailbox/bcm-pdc-mailbox.c b/drivers/mailbox/bcm-pdc-mailbox.c index 5b375985f7b8..4718722c3c67 100644 --- a/drivers/mailbox/bcm-pdc-mailbox.c +++ b/drivers/mailbox/bcm-pdc-mailbox.c @@ -294,9 +294,6 @@ struct pdc_state { unsigned int pdc_irq; - /* tasklet for deferred processing after DMA rx interrupt */ - struct tasklet_struct rx_tasklet; - /* Number of bytes of receive status prior to each rx frame */ u32 rx_status_len; /* Whether a BCM header is prepended to each frame */ @@ -953,23 +950,23 @@ static irqreturn_t pdc_irq_handler(int irq, void *data) iowrite32(intstatus, pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET); /* Wakeup IRQ thread */ - tasklet_schedule(&pdcs->rx_tasklet); - return IRQ_HANDLED; + return IRQ_WAKE_THREAD; } /** - * pdc_tasklet_cb() - Tasklet callback that runs the deferred processing after + * pdc_task_cb() - Threaded IRQ that runs the deferred processing after * a DMA receive interrupt. Reenables the receive interrupt. * @data: PDC state structure */ -static void pdc_tasklet_cb(struct tasklet_struct *t) +static irqreturn_t pdc_task_cb(int irq, void *data) { - struct pdc_state *pdcs = from_tasklet(pdcs, t, rx_tasklet); + struct pdc_state *pdcs = data; pdc_receive(pdcs); /* reenable interrupts */ iowrite32(PDC_INTMASK, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET); + return IRQ_HANDLED; } /** @@ -1405,8 +1402,8 @@ static int pdc_interrupts_init(struct pdc_state *pdcs) dev_dbg(dev, "pdc device %s irq %u for pdcs %p", dev_name(dev), pdcs->pdc_irq, pdcs); - err = devm_request_irq(dev, pdcs->pdc_irq, pdc_irq_handler, 0, - dev_name(dev), dev); + err = devm_request_threaded_irq(dev, pdcs->pdc_irq, pdc_irq_handler, + pdc_task_cb, 0, dev_name(dev), dev); if (err) { dev_err(dev, "IRQ %u request failed with err %d\n", pdcs->pdc_irq, err); @@ -1588,9 +1585,6 @@ static int pdc_probe(struct platform_device *pdev) pdc_hw_init(pdcs); - /* Init tasklet for deferred DMA rx processing */ - tasklet_setup(&pdcs->rx_tasklet, pdc_tasklet_cb); - err = pdc_interrupts_init(pdcs); if (err) goto cleanup_buf_pool; @@ -1606,7 +1600,6 @@ static int pdc_probe(struct platform_device *pdev) return PDC_SUCCESS; cleanup_buf_pool: - tasklet_kill(&pdcs->rx_tasklet); dma_pool_destroy(pdcs->rx_buf_pool); cleanup_ring_pool: @@ -1622,8 +1615,6 @@ static int pdc_remove(struct platform_device *pdev) pdc_free_debugfs(); - tasklet_kill(&pdcs->rx_tasklet); - pdc_hw_disable(pdcs); dma_pool_destroy(pdcs->rx_buf_pool); -- 2.26.2
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