perf/dwc_pcie: Avoid placing cpumask on the stack

In general it's preferable to avoid placing cpumasks on the stack, as
for large values of NR_CPUS these can consume significant amounts of
stack space and make stack overflows more likely.

Use cpumask_any_and_but() to avoid the need for a temporary cpumask on
the stack.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
Reviewed-by: Shuai Xue <xueshuai@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240403155950.2068109-7-dawei.li@shingroup.cn
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/drivers/perf/dwc_pcie_pmu.c b/drivers/perf/dwc_pcie_pmu.c
index 957058ad0099e2faa97c28d22153285983abf045..c5e328f2384194b9e273ef6834662f7f0af630b9 100644 (file)
--- a/drivers/perf/dwc_pcie_pmu.c
+++ b/drivers/perf/dwc_pcie_pmu.c
@@ -690,9 +690,8 @@ static int dwc_pcie_pmu_offline_cpu(unsigned int cpu, struct hlist_node *cpuhp_n
 {
        struct dwc_pcie_pmu *pcie_pmu;
        struct pci_dev *pdev;
-       int node;
-       cpumask_t mask;
        unsigned int target;
+       int node;
 
        pcie_pmu = hlist_entry_safe(cpuhp_node, struct dwc_pcie_pmu, cpuhp_node);
        /* Nothing to do if this CPU doesn't own the PMU */
@@ -702,10 +701,9 @@ static int dwc_pcie_pmu_offline_cpu(unsigned int cpu, struct hlist_node *cpuhp_n
        pcie_pmu->on_cpu = -1;
        pdev = pcie_pmu->pdev;
        node = dev_to_node(&pdev->dev);
-       if (cpumask_and(&mask, cpumask_of_node(node), cpu_online_mask) &&
-           cpumask_andnot(&mask, &mask, cpumask_of(cpu)))
-               target = cpumask_any(&mask);
-       else
+
+       target = cpumask_any_and_but(cpumask_of_node(node), cpu_online_mask, cpu);
+       if (target >= nr_cpu_ids)
                target = cpumask_any_but(cpu_online_mask, cpu);
 
        if (target >= nr_cpu_ids) {