From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Fri, 23 Jan 2015 11:24:15 +0000 Subject: [PATCH] iommu/arm-smmu: use a threaded handler for context interrupts In-Reply-To: <1421970482-11722-1-git-send-email-mitchelh@codeaurora.org> References: <1421970482-11722-1-git-send-email-mitchelh@codeaurora.org> Message-ID: <20150123112415.GD23058@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > --- > 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. Will