genirq: Provide new interfaces for affinity hints
Bugzilla: http://bugzilla.redhat.com/2055300
Upstream Status: Linux
Tested: Boot sanity tested. Nothing actually uses the new interfaces yet
although a number are effected by the change to irq_set_affinity_hint().
commit 65c7cdedeb3026fabcc967a7aae2f755ad4d0783
Author: Thomas Gleixner tglx@linutronix.de
Date: Fri Sep 3 11:24:17 2021 -0400
genirq: Provide new interfaces for affinity hints
The discussion about removing the side effect of irq_set_affinity_hint() of
actually applying the cpumask (if not NULL) as affinity to the interrupt,
unearthed a few unpleasantries:
1) The modular perf drivers rely on the current behaviour for the very
wrong reasons.
2) While none of the other drivers prevents user space from changing
the affinity, a cursorily inspection shows that there are at least
expectations in some drivers.
nowadays ignores the affinity hint) is disabled.
Provide new interfaces:
irq_update_affinity_hint() - Only sets the affinity hint pointer
irq_set_affinity_and_hint() - Set the pointer and apply the affinity to
the interrupt
Make irq_set_affinity_hint() a wrapper around irq_apply_affinity_hint() and
document it to be phased out.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210501021832.743094-1-jesse.brandeburg@intel.com
Link: https://lore.kernel.org/r/20210903152430.244937-2-nitesh@redhat.com
Signed-off-by: Phil Auld pauld@redhat.com
Edited by Phil Auld