selftests/bpf: Add a test for objects stuck in free_by_rcu_ttracegrafted

Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first
free_bulk() starts RCU tasks trace GP and the rest of the elements are
freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear
in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and
waiting_for_gp_ttrace lists are empty.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 102 insertions, 0 deletions

diff --git a/drivers/s390/cio/idset.c b/drivers/s390/cio/idset.c
new file mode 100644
index 000000000..e5f28370a
--- /dev/null
+++ b/drivers/s390/cio/idset.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Copyright IBM Corp. 2007, 2012
+ *    Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include "idset.h"
+#include "css.h"
+
+struct idset {
+	int num_ssid;
+	int num_id;
+	unsigned long bitmap[];
+};
+
+static inline unsigned long idset_bitmap_size(int num_ssid, int num_id)
+{
+	return bitmap_size(size_mul(num_ssid, num_id));
+}
+
+static struct idset *idset_new(int num_ssid, int num_id)
+{
+	struct idset *set;
+
+	set = vmalloc(sizeof(struct idset) +
+		      idset_bitmap_size(num_ssid, num_id));
+	if (set) {
+		set->num_ssid = num_ssid;
+		set->num_id = num_id;
+		memset(set->bitmap, 0, idset_bitmap_size(num_ssid, num_id));
+	}
+	return set;
+}
+
+void idset_free(struct idset *set)
+{
+	vfree(set);
+}
+
+void idset_fill(struct idset *set)
+{
+	memset(set->bitmap, 0xff,
+	       idset_bitmap_size(set->num_ssid, set->num_id));
+}
+
+static inline void idset_add(struct idset *set, int ssid, int id)
+{
+	set_bit(ssid * set->num_id + id, set->bitmap);
+}
+
+static inline void idset_del(struct idset *set, int ssid, int id)
+{
+	clear_bit(ssid * set->num_id + id, set->bitmap);
+}
+
+static inline int idset_contains(struct idset *set, int ssid, int id)
+{
+	return test_bit(ssid * set->num_id + id, set->bitmap);
+}
+
+struct idset *idset_sch_new(void)
+{
+	return idset_new(max_ssid + 1, __MAX_SUBCHANNEL + 1);
+}
+
+void idset_sch_add(struct idset *set, struct subchannel_id schid)
+{
+	idset_add(set, schid.ssid, schid.sch_no);
+}
+
+void idset_sch_del(struct idset *set, struct subchannel_id schid)
+{
+	idset_del(set, schid.ssid, schid.sch_no);
+}
+
+/* Clear ids starting from @schid up to end of subchannel set. */
+void idset_sch_del_subseq(struct idset *set, struct subchannel_id schid)
+{
+	int pos = schid.ssid * set->num_id + schid.sch_no;
+
+	bitmap_clear(set->bitmap, pos, set->num_id - schid.sch_no);
+}
+
+int idset_sch_contains(struct idset *set, struct subchannel_id schid)
+{
+	return idset_contains(set, schid.ssid, schid.sch_no);
+}
+
+int idset_is_empty(struct idset *set)
+{
+	return bitmap_empty(set->bitmap, set->num_ssid * set->num_id);
+}
+
+void idset_add_set(struct idset *to, struct idset *from)
+{
+	int len = min(to->num_ssid * to->num_id, from->num_ssid * from->num_id);
+
+	bitmap_or(to->bitmap, to->bitmap, from->bitmap, len);
+}