[tip: irq/urgent] genirq/irqdesc: Honor caller provided affinity in alloc_desc()

[tip-bot2 for Shay Drory]

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID:     edbbaae42a56f9a2b39c52ef2504dfb3fb0a7858
Gitweb:        https://git.kernel.org/tip/edbbaae42a56f9a2b39c52ef2504dfb3fb0a7858
Author:        Shay Drory <shayd@xxxxxxxxxx>
AuthorDate:    Tue, 06 Aug 2024 10:20:44 +03:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Wed, 07 Aug 2024 17:27:00 +02:00

genirq/irqdesc: Honor caller provided affinity in alloc_desc()

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

---
 kernel/irq/irqdesc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 07e99c9..1dee88b 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++;