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PCI/LINK: Supply IRQ handler so level-triggered IRQs are acked

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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: e8303bb7a7 ("PCI/LINK: Report degraded links via link bandwidth notification")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Alexandru Gagniuc 2019-03-22 19:36:51 -05:00 committed by Bjorn Helgaas
parent 9e98c678c2
commit 3e82a7f903
1 changed files with 14 additions and 5 deletions
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19
drivers/pci/pcie/bw_notification.c
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@ -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;