[PATCH] RecipeCommon: IRQ: check if MSI interrupt is registered

[Jan Tluka]

This is a fix for an issue we hit on specific NIC tracked in
https://bugzilla.redhat.com/show_bug.cgi?id=1484059

In this case the mlx4_core driver lists all available MSI interrupts
under /sys/class/$dev/device/msi_irqs, this covers interrupts for both
mlx4_en (network part) and mlx4_ib (storage part) even if any of these is
not loaded yet. The IRQs are propagated to /proc/irq/ directory once
they're loaded.

To fix this the availability of the interrupt id is first checked in
/proc/irq/ directory and modified only if present.

Signed-off-by: Jan Tluka 
---
 lnst/RecipeCommon/IRQ.py | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/lnst/RecipeCommon/IRQ.py b/lnst/RecipeCommon/IRQ.py
index 88d673b..6b3a2e0 100644
--- a/lnst/RecipeCommon/IRQ.py
+++ b/lnst/RecipeCommon/IRQ.py
@@ -38,4 +38,13 @@ def pin_dev_irqs(machine, device, cpu):
             int(intr)
         except:
             continue
-        machine.config("/proc/irq/%s/smp_affinity_list" % intr.strip(), cpu)
+
+        # some drivers list all _available_ MSI interrupts under msi_irqs
+        # even for driver parts that are not loaded (in case of converged
+        # network adapters) and these interrupts are not visible under
+        # /proc/irq and make LNST report failure so we need to check if the
+        # interrupt is available first
+        list_intr = machine.run("ls -d /proc/irq/%s 2>/dev/null || true" % intr.strip())
+        res = list_intr.get_result()
+        if res["res_data"]["stdout"]:
+            machine.config("/proc/irq/%s/smp_affinity_list" % intr.strip(), cpu)

[Ondrej Lichtner]

On Tue, Oct 02, 2018 at 11:03:32AM +0200, Jan Tluka wrote:
> This is a fix for an issue we hit on specific NIC tracked in
> https://bugzilla.redhat.com/show_bug.cgi?id=1484059
>
> In this case the mlx4_core driver lists all available MSI interrupts
> under /sys/class/$dev/device/msi_irqs, this covers interrupts for both
> mlx4_en (network part) and mlx4_ib (storage part) even if any of these is
> not loaded yet. The IRQs are propagated to /proc/irq/ directory once
> they're loaded.
>
> To fix this the availability of the interrupt id is first checked in
> /proc/irq/ directory and modified only if present.
> Signed-off-by: Jan Tluka
>
> lnst/RecipeCommon/IRQ.py | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/lnst/RecipeCommon/IRQ.py b/lnst/RecipeCommon/IRQ.py
> index 88d673b..6b3a2e0 100644
> --- a/lnst/RecipeCommon/IRQ.py
> +++ b/lnst/RecipeCommon/IRQ.py
> @@ -38,4 +38,13 @@ def pin_dev_irqs(machine, device, cpu):
>              int(intr)
>          except:
>              continue
>    machine.config("/proc/irq/%s/smp_affinity_list" % intr.strip(), cpu)
>    # some drivers list all _available_ MSI interrupts under msi_irqs
>    # even for driver parts that are not loaded (in case of converged
>    # network adapters) and these interrupts are not visible under
>    # /proc/irq and make LNST report failure so we need to check if the
>    # interrupt is available first
>    list_intr = machine.run("ls -d /proc/irq/%s 2>/dev/null || true" % intr.strip())

AH! I do have a suggestion for this...

Can the "ls -d ..." command be moved outside of the loop so it isn't
executed for each IRQ?

-Ondrej