irqchip/gic-v3-its: Limit memreserve cpuhp state lifetime

The new memreserve cpuhp callback only needs to survive up until a point
where every CPU in the system has booted once. Beyond that, it becomes a
no-op and can be put in the bin.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211027151506.2085066-4-valentin.schneider@arm.com

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index f860733d3e4e13c38947a6b2b69677010026ea79..ee83eb377d7ed7874f016596c594d50f9f02ccf9 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -5203,6 +5203,15 @@ int its_cpu_init(void)
        return 0;
 }
 
+static void rdist_memreserve_cpuhp_cleanup_workfn(struct work_struct *work)
+{
+       cpuhp_remove_state_nocalls(gic_rdists->cpuhp_memreserve_state);
+       gic_rdists->cpuhp_memreserve_state = CPUHP_INVALID;
+}
+
+static DECLARE_WORK(rdist_memreserve_cpuhp_cleanup_work,
+                   rdist_memreserve_cpuhp_cleanup_workfn);
+
 static int its_cpu_memreserve_lpi(unsigned int cpu)
 {
        struct page *pend_page;
@@ -5231,6 +5240,10 @@ static int its_cpu_memreserve_lpi(unsigned int cpu)
        }
 
 out:
+       /* Last CPU being brought up gets to issue the cleanup */
+       if (cpumask_equal(&cpus_booted_once_mask, cpu_possible_mask))
+               schedule_work(&rdist_memreserve_cpuhp_cleanup_work);
+
        gic_data_rdist()->flags |= RD_LOCAL_MEMRESERVE_DONE;
        return ret;
 }
@@ -5425,6 +5438,7 @@ int __init its_lpi_memreserve_init(void)
        if (!efi_enabled(EFI_CONFIG_TABLES))
                return 0;
 
+       gic_rdists->cpuhp_memreserve_state = CPUHP_INVALID;
        state = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
                                  "irqchip/arm/gicv3/memreserve:online",
                                  its_cpu_memreserve_lpi,
@@ -5432,6 +5446,8 @@ int __init its_lpi_memreserve_init(void)
        if (state < 0)
                return state;
 
+       gic_rdists->cpuhp_memreserve_state = state;
+
        return 0;
 }
 

diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index 51b85506ae90265098b93c300a3cc21db15ba7b8..12d91f0dedf90caa46f6b8ceef81e876c97fb926 100644 (file)
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -624,6 +624,7 @@ struct rdists {
        u64                     flags;
        u32                     gicd_typer;
        u32                     gicd_typer2;
+       int                     cpuhp_memreserve_state;
        bool                    has_vlpis;
        bool                    has_rvpeid;
        bool                    has_direct_lpi;