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SubjectRe: [PATCH v2] PCI/LINK: bw_notification: Do not leave interrupt handler NULL
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On 3/25/19 5:25 PM, 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

You're so much better at formulating commit messages. That sounds a lot
smoother. Thanks!

>> ---
>> 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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