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author | Davidlohr Bueso <dave@stgolabs.net> | 2021-01-14 16:20:14 -0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-01-27 14:57:06 +0100 |
commit | 2c104a469a4ce276117acda94ccf922c3b82d735 (patch) | |
tree | bf0019b21384ea7c23f52836db5e18ab92b16d8c /drivers/platform | |
parent | afe9017901761d04a106916e02619caf0d2afbf5 (diff) | |
download | linux-stable-2c104a469a4ce276117acda94ccf922c3b82d735.tar.gz linux-stable-2c104a469a4ce276117acda94ccf922c3b82d735.tar.bz2 linux-stable-2c104a469a4ce276117acda94ccf922c3b82d735.zip |
platform/goldfish: Convert pipe tasklet to threaded irq
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 deal with the signaled
pipes in task context.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210115002014.117528-1-dave@stgolabs.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/platform')
-rw-r--r-- | drivers/platform/goldfish/goldfish_pipe.c | 28 |
1 files changed, 11 insertions, 17 deletions
diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c index 1ab207ec9c94..b67539f9848c 100644 --- a/drivers/platform/goldfish/goldfish_pipe.c +++ b/drivers/platform/goldfish/goldfish_pipe.c @@ -212,9 +212,6 @@ struct goldfish_pipe_dev { int version; unsigned char __iomem *base; - /* an irq tasklet to run goldfish_interrupt_task */ - struct tasklet_struct irq_tasklet; - struct miscdevice miscdev; }; @@ -577,10 +574,10 @@ static struct goldfish_pipe *signalled_pipes_pop_front( return pipe; } -static void goldfish_interrupt_task(unsigned long dev_addr) +static irqreturn_t goldfish_interrupt_task(int irq, void *dev_addr) { /* Iterate over the signalled pipes and wake them one by one */ - struct goldfish_pipe_dev *dev = (struct goldfish_pipe_dev *)dev_addr; + struct goldfish_pipe_dev *dev = dev_addr; struct goldfish_pipe *pipe; int wakes; @@ -599,13 +596,14 @@ static void goldfish_interrupt_task(unsigned long dev_addr) */ wake_up_interruptible(&pipe->wake_queue); } + return IRQ_HANDLED; } static void goldfish_pipe_device_deinit(struct platform_device *pdev, struct goldfish_pipe_dev *dev); /* - * The general idea of the interrupt handling: + * The general idea of the (threaded) interrupt handling: * * 1. device raises an interrupt if there's at least one signalled pipe * 2. IRQ handler reads the signalled pipes and their count from the device @@ -614,8 +612,8 @@ static void goldfish_pipe_device_deinit(struct platform_device *pdev, * otherwise it leaves it raised, so IRQ handler will be called * again for the next chunk * 4. IRQ handler adds all returned pipes to the device's signalled pipes list - * 5. IRQ handler launches a tasklet to process the signalled pipes from the - * list in a separate context + * 5. IRQ handler defers processing the signalled pipes from the list in a + * separate context */ static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id) { @@ -645,8 +643,7 @@ static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id) spin_unlock_irqrestore(&dev->lock, flags); - tasklet_schedule(&dev->irq_tasklet); - return IRQ_HANDLED; + return IRQ_WAKE_THREAD; } static int get_free_pipe_id_locked(struct goldfish_pipe_dev *dev) @@ -811,12 +808,10 @@ static int goldfish_pipe_device_init(struct platform_device *pdev, { int err; - tasklet_init(&dev->irq_tasklet, &goldfish_interrupt_task, - (unsigned long)dev); - - err = devm_request_irq(&pdev->dev, dev->irq, - goldfish_pipe_interrupt, - IRQF_SHARED, "goldfish_pipe", dev); + err = devm_request_threaded_irq(&pdev->dev, dev->irq, + goldfish_pipe_interrupt, + goldfish_interrupt_task, + IRQF_SHARED, "goldfish_pipe", dev); if (err) { dev_err(&pdev->dev, "unable to allocate IRQ for v2\n"); return err; @@ -874,7 +869,6 @@ static void goldfish_pipe_device_deinit(struct platform_device *pdev, struct goldfish_pipe_dev *dev) { misc_deregister(&dev->miscdev); - tasklet_kill(&dev->irq_tasklet); kfree(dev->pipes); free_page((unsigned long)dev->buffers); } |