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-rw-r--r--kernel/bpf/Makefile2
-rw-r--r--kernel/bpf/percpu_freelist.c100
-rw-r--r--kernel/bpf/percpu_freelist.h31
3 files changed, 132 insertions, 1 deletions
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
index 8a932d079c24..eed911d091da 100644
--- a/kernel/bpf/Makefile
+++ b/kernel/bpf/Makefile
@@ -1,7 +1,7 @@
obj-y := core.o
obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o
-obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o
+obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o
ifeq ($(CONFIG_PERF_EVENTS),y)
obj-$(CONFIG_BPF_SYSCALL) += stackmap.o
endif
diff --git a/kernel/bpf/percpu_freelist.c b/kernel/bpf/percpu_freelist.c
new file mode 100644
index 000000000000..5c51d1985b51
--- /dev/null
+++ b/kernel/bpf/percpu_freelist.c
@@ -0,0 +1,100 @@
+/* Copyright (c) 2016 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#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;
+ }
+ return 0;
+}
+
+void pcpu_freelist_destroy(struct pcpu_freelist *s)
+{
+ free_percpu(s->freelist);
+}
+
+static inline void __pcpu_freelist_push(struct pcpu_freelist_head *head,
+ struct pcpu_freelist_node *node)
+{
+ raw_spin_lock(&head->lock);
+ node->next = head->first;
+ head->first = node;
+ raw_spin_unlock(&head->lock);
+}
+
+void pcpu_freelist_push(struct pcpu_freelist *s,
+ struct pcpu_freelist_node *node)
+{
+ struct pcpu_freelist_head *head = this_cpu_ptr(s->freelist);
+
+ __pcpu_freelist_push(head, node);
+}
+
+void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
+ u32 nr_elems)
+{
+ struct pcpu_freelist_head *head;
+ unsigned long flags;
+ int i, cpu, pcpu_entries;
+
+ pcpu_entries = nr_elems / num_possible_cpus() + 1;
+ i = 0;
+
+ /* disable irq to workaround lockdep false positive
+ * in bpf usage pcpu_freelist_populate() will never race
+ * with pcpu_freelist_push()
+ */
+ local_irq_save(flags);
+ for_each_possible_cpu(cpu) {
+again:
+ head = per_cpu_ptr(s->freelist, cpu);
+ __pcpu_freelist_push(head, buf);
+ i++;
+ buf += elem_size;
+ if (i == nr_elems)
+ break;
+ if (i % pcpu_entries)
+ goto again;
+ }
+ local_irq_restore(flags);
+}
+
+struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
+{
+ struct pcpu_freelist_head *head;
+ struct pcpu_freelist_node *node;
+ int orig_cpu, cpu;
+
+ orig_cpu = cpu = raw_smp_processor_id();
+ while (1) {
+ head = per_cpu_ptr(s->freelist, cpu);
+ raw_spin_lock(&head->lock);
+ node = head->first;
+ if (node) {
+ head->first = node->next;
+ raw_spin_unlock(&head->lock);
+ return node;
+ }
+ raw_spin_unlock(&head->lock);
+ cpu = cpumask_next(cpu, cpu_possible_mask);
+ if (cpu >= nr_cpu_ids)
+ cpu = 0;
+ if (cpu == orig_cpu)
+ return NULL;
+ }
+}
diff --git a/kernel/bpf/percpu_freelist.h b/kernel/bpf/percpu_freelist.h
new file mode 100644
index 000000000000..3049aae8ea1e
--- /dev/null
+++ b/kernel/bpf/percpu_freelist.h
@@ -0,0 +1,31 @@
+/* Copyright (c) 2016 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#ifndef __PERCPU_FREELIST_H__
+#define __PERCPU_FREELIST_H__
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
+
+struct pcpu_freelist_head {
+ struct pcpu_freelist_node *first;
+ raw_spinlock_t lock;
+};
+
+struct pcpu_freelist {
+ struct pcpu_freelist_head __percpu *freelist;
+};
+
+struct pcpu_freelist_node {
+ struct pcpu_freelist_node *next;
+};
+
+void pcpu_freelist_push(struct pcpu_freelist *, struct pcpu_freelist_node *);
+struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *);
+void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
+ u32 nr_elems);
+int pcpu_freelist_init(struct pcpu_freelist *);
+void pcpu_freelist_destroy(struct pcpu_freelist *s);
+#endif