seq_file: add seq_list_*_percpu helpers

When we convert the file_lock_list to a set of percpu lists, we'll need a way to iterate over them in order to output /proc/locks info. Add some seq_list_*_percpu helpers to handle that. Signed-off-by: Jeff Layton <jlayton@redhat.com> Acked-by: J. Bruce Fields <bfields@fieldses.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

seq_file: add seq_list_*_percpu helpers
When we convert the file_lock_list to a set of percpu lists, we'll need a way to iterate over them in order to output /proc/locks info. Add some seq_list_*_percpu helpers to handle that. Signed-off-by: Jeff Layton <jlayton@redhat.com> Acked-by: J. Bruce Fields <bfields@fieldses.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Jeff Layton · Al Viro
1 parent 99b072bb38
Showing 2 changed files with 60 additions and 0 deletions Side-by-side Diff
fs/seq_file.c
include/linux/seq_file.h
@@ -921,4 +921,58 @@
 		return rcu_dereference(node->next);
 }
 EXPORT_SYMBOL(seq_hlist_next_rcu);
+
+/**
+ * seq_hlist_start_precpu - start an iteration of a percpu hlist array
+ * @head: pointer to percpu array of struct hlist_heads
+ * @cpu:  pointer to cpu "cursor"
+ * @pos:  start position of sequence
+ *
+ * Called at seq_file->op->start().
+ */
+struct hlist_node *
+seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
+{
+	struct hlist_node *node;
+
+	for_each_possible_cpu(*cpu) {
+		hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
+			if (pos-- == 0)
+				return node;
+		}
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(seq_hlist_start_percpu);
+
+/**
+ * seq_hlist_next_percpu - move to the next position of the percpu hlist array
+ * @v:    pointer to current hlist_node
+ * @head: pointer to percpu array of struct hlist_heads
+ * @cpu:  pointer to cpu "cursor"
+ * @pos:  start position of sequence
+ *
+ * Called at seq_file->op->next().
+ */
+struct hlist_node *
+seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
+			int *cpu, loff_t *pos)
+{
+	struct hlist_node *node = v;
+
+	++*pos;
+
+	if (node->next)
+		return node->next;
+
+	for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
+	     *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
+		struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
+
+		if (!hlist_empty(bucket))
+			return bucket->first;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(seq_hlist_next_percpu);
@@ -173,5 +173,11 @@
 extern struct hlist_node *seq_hlist_next_rcu(void *v,
 						   struct hlist_head *head,
 						   loff_t *ppos);
+
+/* Helpers for iterating over per-cpu hlist_head-s in seq_files */
+extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
+
+extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
+
 #endif
...	...	@@ -921,4 +921,58 @@
921	921	return rcu_dereference(node->next);
922	922	}
923	923	EXPORT_SYMBOL(seq_hlist_next_rcu);
	924	+
	925	+/**
	926	+ * seq_hlist_start_precpu - start an iteration of a percpu hlist array
	927	+ * @head: pointer to percpu array of struct hlist_heads
	928	+ * @cpu: pointer to cpu "cursor"
	929	+ * @pos: start position of sequence
	930	+ *
	931	+ * Called at seq_file->op->start().
	932	+ */
	933	+struct hlist_node *
	934	+seq_hlist_start_percpu(struct hlist_head __percpu head, int cpu, loff_t pos)
	935	+{
	936	+ struct hlist_node *node;
	937	+
	938	+ for_each_possible_cpu(*cpu) {
	939	+ hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
	940	+ if (pos-- == 0)
	941	+ return node;
	942	+ }
	943	+ }
	944	+ return NULL;
	945	+}
	946	+EXPORT_SYMBOL(seq_hlist_start_percpu);
	947	+
	948	+/**
	949	+ * seq_hlist_next_percpu - move to the next position of the percpu hlist array
	950	+ * @v: pointer to current hlist_node
	951	+ * @head: pointer to percpu array of struct hlist_heads
	952	+ * @cpu: pointer to cpu "cursor"
	953	+ * @pos: start position of sequence
	954	+ *
	955	+ * Called at seq_file->op->next().
	956	+ */
	957	+struct hlist_node *
	958	+seq_hlist_next_percpu(void v, struct hlist_head __percpu head,
	959	+ int cpu, loff_t pos)
	960	+{
	961	+ struct hlist_node *node = v;
	962	+
	963	+ ++*pos;
	964	+
	965	+ if (node->next)
	966	+ return node->next;
	967	+
	968	+ for (cpu = cpumask_next(cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
	969	+ cpu = cpumask_next(cpu, cpu_possible_mask)) {
	970	+ struct hlist_head bucket = per_cpu_ptr(head, cpu);
	971	+
	972	+ if (!hlist_empty(bucket))
	973	+ return bucket->first;
	974	+ }
	975	+ return NULL;
	976	+}
	977	+EXPORT_SYMBOL(seq_hlist_next_percpu);
...	...	@@ -173,5 +173,11 @@
173	173	extern struct hlist_node seq_hlist_next_rcu(void v,
174	174	struct hlist_head *head,
175	175	loff_t *ppos);
	176	+
	177	+/* Helpers for iterating over per-cpu hlist_head-s in seq_files */
	178	+extern struct hlist_node seq_hlist_start_percpu(struct hlist_head __percpu head, int *cpu, loff_t pos);
	179	+
	180	+extern struct hlist_node seq_hlist_next_percpu(void v, struct hlist_head __percpu head, int cpu, loff_t *pos);
	181	+
176	182	#endif