On Fri, Jan 23 2015 at 03:24:15 AM, Will Deacon <[email protected]> wrote: > Hi Mitch, > > On Thu, Jan 22, 2015 at 11:48:02PM +0000, Mitchel Humpherys wrote: >> Context interrupts can call domain-specific handlers which might sleep. >> Currently we register our handler with request_irq, so our handler is >> called in atomic context, so domain handlers that sleep result in an >> invalid context BUG. Fix this by using request_threaded_irq. >> >> This also prepares the way for doing things like enabling clocks within >> our interrupt handler. >> >> Signed-off-by: Mitchel Humpherys <[email protected]> >> --- >> drivers/iommu/arm-smmu.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >> index 6cd47b75286f..81f6b54d94b1 100644 >> --- a/drivers/iommu/arm-smmu.c >> +++ b/drivers/iommu/arm-smmu.c >> @@ -973,8 +973,9 @@ static int arm_smmu_init_domain_context(struct >> iommu_domain *domain, >> spin_unlock_irqrestore(&smmu_domain->lock, flags); >> >> irq = smmu->irqs[smmu->num_global_irqs + cfg->irptndx]; >> - ret = request_irq(irq, arm_smmu_context_fault, IRQF_SHARED, >> - "arm-smmu-context-fault", domain); >> + ret = request_threaded_irq(irq, NULL, arm_smmu_context_fault, >> + IRQF_ONESHOT | IRQF_SHARED, >> + "arm-smmu-context-fault", domain); >> if (IS_ERR_VALUE(ret)) { >> dev_err(smmu->dev, "failed to request context IRQ %d (%u)\n", >> cfg->irptndx, irq); > > I think I'd rather keep a simple atomic handler, then have a threaded > handler for actually issuing the report_iommu_fault. i.e. we only wake > the thread when it looks like there's some work to do. That also works > much better for shared interrupts.
Are you still against adding clock support to the driver? If not, we'll need to move to a threaded handler when clocks come in anyways... Can you elaborate what you mean regarding shared interrupts? Even without clocks it seems like the code clarity / performance tradeoff would favor a threaded handler, given that performance isn't important here. -Mitch -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
