Messages in this thread | | | Subject | Re: [PATCH v2] PCI: dra7xx: mark dra7xx_pcie_msi irq as IRQF_NO_THREAD | From | Grygorii Strashko <> | Date | Wed, 9 Dec 2015 21:38:05 +0200 |
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On 12/09/2015 05:24 PM, Bjorn Helgaas wrote: > On Tue, Dec 08, 2015 at 10:05:56AM +0100, Sebastian Andrzej Siewior wrote: >> * Bjorn Helgaas | 2015-12-04 12:46:19 [-0600]: >> >>> The backtrace might be OK (maybe slightly overkill), but all the >>> stack addresses are certainly irrelevant and distracting. We only >>> need enough to recognize the problem. I don't think the modules list >>> is relevant either. >> >> I would shorten it to the bare minimum. Also the patch description >> itself could be truncated to the required bits… >> >>>> diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-dra7xx.c >>>> index 8c36880..0415192 100644 >>>> --- a/drivers/pci/host/pci-dra7xx.c >>>> +++ b/drivers/pci/host/pci-dra7xx.c >>>> @@ -301,8 +301,19 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx, >>>> return -EINVAL; >>>> } >>>> >>>> + /* >>>> + * Mark dra7xx_pcie_msi IRQ as IRQF_NO_THREAD >>>> + * On -RT and if kernel is booting with "threadirqs" cmd line parameter >>>> + * the dra7xx_pcie_msi_irq_handler() will be forced threaded but, >>>> + * in the same time, it's IRQ dispatcher and calls generic_handle_irq(), >>>> + * which, in turn, will be resolved to handle_simple_irq() call. >>>> + * The handle_simple_irq() expected to be called with IRQ disabled, as >>>> + * result kernle will display warning: >>>> + * "irq XXX handler YYY+0x0/0x14 enabled interrupts". >>>> + */ >> >> …not to mention this piece. d7ce4377494a ("powerpc/fsl_msi: mark the msi >> cascade handler IRQF_NO_THREAD") fixes the same bug in arch/ppc so they >> bypassed you fixing it. >> >>>> ret = devm_request_irq(&pdev->dev, pp->irq, >>>> - dra7xx_pcie_msi_irq_handler, IRQF_SHARED, >>>> + dra7xx_pcie_msi_irq_handler, >>>> + IRQF_SHARED | IRQF_NO_THREAD, >>>> "dra7-pcie-msi", pp); >>> >>> There's similar code in exynos_add_pcie_port(), imx6_add_pcie_port(), >>> and spear13xx_add_pcie_port(). Do they need similar changes? If not, >>> why not? >> >> You are right. The request for the handler exynos_pcie_msi_irq_handler(), >> imx6_pcie_msi_handler() and spear13xx_pcie_irq_handler() needs same >> treatment. >> Additionally we have: >> >> arch/mips/pci/msi-octeon.c: if (request_irq(OCTEON_IRQ_PCI_MSI0, octeon_msi_interrupt0, >> arch/sparc/kernel/pci_msi.c: err = request_irq(irq, sparc64_msiq_interrupt, 0, >> drivers/pci/host/pci-tegra.c: err = request_irq(msi->irq, tegra_pcie_msi_irq, 0, >> drivers/pci/host/pcie-rcar.c: err = devm_request_irq(&pdev->dev, msi->irq1, rcar_pcie_msi_irq, >> drivers/pci/host/pcie-rcar.c: err = devm_request_irq(&pdev->dev, msi->irq2, rcar_pcie_msi_irq, >> drivers/pci/host/pcie-xilinx.c: err = devm_request_irq(dev, port->irq, xilinx_pcie_intr_handler, >> >> which require the same kind of fix… >> >>> I see your discussion about DRA7 hardware design, but my impression is >>> that this problem affects anybody who calls dw_handle_msi_irq() from a >>> handler registered with IRQF_SHARED. >> >> … brecause all of them invoke generic_handle_irq() from the requsted >> handler. generic_handle_irq grabs raw_locks and this needs to run in >> raw-irq context. >> IRQF_SHARED could probably go away. The IRQ is mostlikely exclusive >> assigned in each SoC for MSI interrupt demux. > > It sounds like we should fix all these places at once. If you > (Grygorii) work up a patch that does them all, with a more generic > changelog, then we can solicit testing and acks.
Sure, will do: - change will be applied for files listed in this thread only - IRQF_SHARED will be left unchanged - commit message will be made more generic - i prefer to keep comment in code for dra7 as is. Is it ok?
-- regards, -grygorii
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