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    SubjectRe: [PATCH v2] PCI/LINK: bw_notification: Do not leave interrupt handler NULL
    [+cc Borislav]

    Hi Borislav, sorry; I meant to cc: you when I applied the patch below.
    I did add a Reported-by for you.

    On Mon, Mar 25, 2019 at 05:25:02PM -0500, Bjorn Helgaas wrote:
    > On Fri, Mar 22, 2019 at 07:36:51PM -0500, Alexandru Gagniuc wrote:
    > > A threaded IRQ with a NULL handler does not work with level-triggered
    > > interrupts. request_threaded_irq() will return an error:
    > >
    > > genirq: Threaded irq requested with handler=NULL and !ONESHOT for irq 16
    > > pcie_bw_notification: probe of 0000:00:1b.0:pcie010 failed with error -22
    > >
    > > For level interrupts we need to silence the interrupt before exiting
    > > the IRQ handler, so just clear the PCI_EXP_LNKSTA_LBMS bit there.
    > >
    > > Fixes: e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification")
    > > Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
    > > Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
    >
    > Applied with the following subject line to for-linus for v5.1, thanks!
    >
    > PCI/LINK: Supply IRQ handler so level-triggered IRQs are acked
    >
    > > ---
    > > Changes since v1:
    > > - move pcie_update_link_speed() to irq to prevent duplicate read of link_status
    > > - Add Fixes: to commit message
    > >
    > > drivers/pci/pcie/bw_notification.c | 19 ++++++++++++++-----
    > > 1 file changed, 14 insertions(+), 5 deletions(-)
    > >
    > > diff --git a/drivers/pci/pcie/bw_notification.c b/drivers/pci/pcie/bw_notification.c
    > > index d2eae3b7cc0f..c48746f1cf3c 100644
    > > --- a/drivers/pci/pcie/bw_notification.c
    > > +++ b/drivers/pci/pcie/bw_notification.c
    > > @@ -44,11 +44,10 @@ static void pcie_disable_link_bandwidth_notification(struct pci_dev *dev)
    > > pcie_capability_write_word(dev, PCI_EXP_LNKCTL, lnk_ctl);
    > > }
    > >
    > > -static irqreturn_t pcie_bw_notification_handler(int irq, void *context)
    > > +static irqreturn_t pcie_bw_notification_irq(int irq, void *context)
    > > {
    > > struct pcie_device *srv = context;
    > > struct pci_dev *port = srv->port;
    > > - struct pci_dev *dev;
    > > u16 link_status, events;
    > > int ret;
    > >
    > > @@ -58,6 +57,17 @@ static irqreturn_t pcie_bw_notification_handler(int irq, void *context)
    > > if (ret != PCIBIOS_SUCCESSFUL || !events)
    > > return IRQ_NONE;
    > >
    > > + pcie_capability_write_word(port, PCI_EXP_LNKSTA, events);
    > > + pcie_update_link_speed(port->subordinate, link_status);
    > > + return IRQ_WAKE_THREAD;
    > > +}
    > > +
    > > +static irqreturn_t pcie_bw_notification_handler(int irq, void *context)
    > > +{
    > > + struct pcie_device *srv = context;
    > > + struct pci_dev *port = srv->port;
    > > + struct pci_dev *dev;
    > > +
    > > /*
    > > * Print status from downstream devices, not this root port or
    > > * downstream switch port.
    > > @@ -67,8 +77,6 @@ static irqreturn_t pcie_bw_notification_handler(int irq, void *context)
    > > __pcie_print_link_status(dev, false);
    > > up_read(&pci_bus_sem);
    > >
    > > - pcie_update_link_speed(port->subordinate, link_status);
    > > - pcie_capability_write_word(port, PCI_EXP_LNKSTA, events);
    > > return IRQ_HANDLED;
    > > }
    > >
    > > @@ -80,7 +88,8 @@ static int pcie_bandwidth_notification_probe(struct pcie_device *srv)
    > > if (!pcie_link_bandwidth_notification_supported(srv->port))
    > > return -ENODEV;
    > >
    > > - ret = request_threaded_irq(srv->irq, NULL, pcie_bw_notification_handler,
    > > + ret = request_threaded_irq(srv->irq, pcie_bw_notification_irq,
    > > + pcie_bw_notification_handler,
    > > IRQF_SHARED, "PCIe BW notif", srv);
    > > if (ret)
    > > return ret;
    > > --
    > > 2.19.2
    > >

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