Currently, whenever a caller is providing an affinity hint for an
interrupt, the allocation code uses it to calculate the node and copies the
cpumask into irq_desc::affinity.
If the affinity for the interrupt is not marked 'managed' then the startup
of the interrupt ignores irq_desc::affinity and uses the system default
affinity mask.
Prevent this by setting the IRQD_AFFINITY_SET flag for the interrupt in the
allocator, which causes irq_setup_affinity() to use irq_desc::affinity on
interrupt startup if the mask contains an online CPU.
[ tglx: Massaged changelog ]
Fixes: 45ddcecbfa94 ("genirq: Use affinity hint in irqdesc allocation")
Signed-off-by: Shay Drory <shayd@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20240806072044.837827-1-shayd@xxxxxxxxxx
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 07e99c936ba5..1dee88ba0ae4 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -530,6 +530,7 @@ static int alloc_descs(unsigned int start, unsigned int cnt, int node,
flags = IRQD_AFFINITY_MANAGED |
IRQD_MANAGED_SHUTDOWN;
}
+ flags |= IRQD_AFFINITY_SET;
mask = &affinity->mask;
node = cpu_to_node(cpumask_first(mask));
affinity++;
