From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- kernel/bpf/percpu_freelist.c | 200 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) create mode 100644 kernel/bpf/percpu_freelist.c (limited to 'kernel/bpf/percpu_freelist.c') diff --git a/kernel/bpf/percpu_freelist.c b/kernel/bpf/percpu_freelist.c new file mode 100644 index 000000000..034cf87b5 --- /dev/null +++ b/kernel/bpf/percpu_freelist.c @@ -0,0 +1,200 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2016 Facebook + */ +#include "percpu_freelist.h" + +int pcpu_freelist_init(struct pcpu_freelist *s) +{ + int cpu; + + s->freelist = alloc_percpu(struct pcpu_freelist_head); + if (!s->freelist) + return -ENOMEM; + + for_each_possible_cpu(cpu) { + struct pcpu_freelist_head *head = per_cpu_ptr(s->freelist, cpu); + + raw_spin_lock_init(&head->lock); + head->first = NULL; + } + raw_spin_lock_init(&s->extralist.lock); + s->extralist.first = NULL; + return 0; +} + +void pcpu_freelist_destroy(struct pcpu_freelist *s) +{ + free_percpu(s->freelist); +} + +static inline void pcpu_freelist_push_node(struct pcpu_freelist_head *head, + struct pcpu_freelist_node *node) +{ + node->next = head->first; + WRITE_ONCE(head->first, node); +} + +static inline void ___pcpu_freelist_push(struct pcpu_freelist_head *head, + struct pcpu_freelist_node *node) +{ + raw_spin_lock(&head->lock); + pcpu_freelist_push_node(head, node); + raw_spin_unlock(&head->lock); +} + +static inline bool pcpu_freelist_try_push_extra(struct pcpu_freelist *s, + struct pcpu_freelist_node *node) +{ + if (!raw_spin_trylock(&s->extralist.lock)) + return false; + + pcpu_freelist_push_node(&s->extralist, node); + raw_spin_unlock(&s->extralist.lock); + return true; +} + +static inline void ___pcpu_freelist_push_nmi(struct pcpu_freelist *s, + struct pcpu_freelist_node *node) +{ + int cpu, orig_cpu; + + orig_cpu = raw_smp_processor_id(); + while (1) { + for_each_cpu_wrap(cpu, cpu_possible_mask, orig_cpu) { + struct pcpu_freelist_head *head; + + head = per_cpu_ptr(s->freelist, cpu); + if (raw_spin_trylock(&head->lock)) { + pcpu_freelist_push_node(head, node); + raw_spin_unlock(&head->lock); + return; + } + } + + /* cannot lock any per cpu lock, try extralist */ + if (pcpu_freelist_try_push_extra(s, node)) + return; + } +} + +void __pcpu_freelist_push(struct pcpu_freelist *s, + struct pcpu_freelist_node *node) +{ + if (in_nmi()) + ___pcpu_freelist_push_nmi(s, node); + else + ___pcpu_freelist_push(this_cpu_ptr(s->freelist), node); +} + +void pcpu_freelist_push(struct pcpu_freelist *s, + struct pcpu_freelist_node *node) +{ + unsigned long flags; + + local_irq_save(flags); + __pcpu_freelist_push(s, node); + local_irq_restore(flags); +} + +void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size, + u32 nr_elems) +{ + struct pcpu_freelist_head *head; + unsigned int cpu, cpu_idx, i, j, n, m; + + n = nr_elems / num_possible_cpus(); + m = nr_elems % num_possible_cpus(); + + cpu_idx = 0; + for_each_possible_cpu(cpu) { + head = per_cpu_ptr(s->freelist, cpu); + j = n + (cpu_idx < m ? 1 : 0); + for (i = 0; i < j; i++) { + /* No locking required as this is not visible yet. */ + pcpu_freelist_push_node(head, buf); + buf += elem_size; + } + cpu_idx++; + } +} + +static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s) +{ + struct pcpu_freelist_head *head; + struct pcpu_freelist_node *node; + int cpu; + + for_each_cpu_wrap(cpu, cpu_possible_mask, raw_smp_processor_id()) { + head = per_cpu_ptr(s->freelist, cpu); + if (!READ_ONCE(head->first)) + continue; + raw_spin_lock(&head->lock); + node = head->first; + if (node) { + WRITE_ONCE(head->first, node->next); + raw_spin_unlock(&head->lock); + return node; + } + raw_spin_unlock(&head->lock); + } + + /* per cpu lists are all empty, try extralist */ + if (!READ_ONCE(s->extralist.first)) + return NULL; + raw_spin_lock(&s->extralist.lock); + node = s->extralist.first; + if (node) + WRITE_ONCE(s->extralist.first, node->next); + raw_spin_unlock(&s->extralist.lock); + return node; +} + +static struct pcpu_freelist_node * +___pcpu_freelist_pop_nmi(struct pcpu_freelist *s) +{ + struct pcpu_freelist_head *head; + struct pcpu_freelist_node *node; + int cpu; + + for_each_cpu_wrap(cpu, cpu_possible_mask, raw_smp_processor_id()) { + head = per_cpu_ptr(s->freelist, cpu); + if (!READ_ONCE(head->first)) + continue; + if (raw_spin_trylock(&head->lock)) { + node = head->first; + if (node) { + WRITE_ONCE(head->first, node->next); + raw_spin_unlock(&head->lock); + return node; + } + raw_spin_unlock(&head->lock); + } + } + + /* cannot pop from per cpu lists, try extralist */ + if (!READ_ONCE(s->extralist.first) || !raw_spin_trylock(&s->extralist.lock)) + return NULL; + node = s->extralist.first; + if (node) + WRITE_ONCE(s->extralist.first, node->next); + raw_spin_unlock(&s->extralist.lock); + return node; +} + +struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *s) +{ + if (in_nmi()) + return ___pcpu_freelist_pop_nmi(s); + return ___pcpu_freelist_pop(s); +} + +struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s) +{ + struct pcpu_freelist_node *ret; + unsigned long flags; + + local_irq_save(flags); + ret = __pcpu_freelist_pop(s); + local_irq_restore(flags); + return ret; +} -- cgit v1.2.3