[PATCH] bpf: add bpf_msleep_interruptible()

[Sergey Senozhatsky]

bpf_msleep_interruptible() puts a calling context into an
interruptible sleep.  This function is expected to be used
for testing only (perhaps in conjunction with fault-injection)
to simulate various execution delays or timeouts.

Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
---
 include/linux/bpf.h            |  1 +
 include/uapi/linux/bpf.h       |  9 +++++++++
 kernel/bpf/helpers.c           | 13 +++++++++++++
 kernel/trace/bpf_trace.c       |  2 ++
 tools/include/uapi/linux/bpf.h |  9 +++++++++
 5 files changed, 34 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 3f0cc89c0622..85bd1daaa7df 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -3392,6 +3392,7 @@ extern const struct bpf_func_proto bpf_get_retval_proto;
 extern const struct bpf_func_proto bpf_user_ringbuf_drain_proto;
 extern const struct bpf_func_proto bpf_cgrp_storage_get_proto;
 extern const struct bpf_func_proto bpf_cgrp_storage_delete_proto;
+extern const struct bpf_func_proto bpf_msleep_interruptible_proto;
 
 const struct bpf_func_proto *tracing_prog_func_proto(
   enum bpf_func_id func_id, const struct bpf_prog *prog);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 71d5ac83cf5d..cbbb6d70a7a3 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5814,6 +5814,14 @@ union bpf_attr {
  *		0 on success.
  *
  *		**-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ * long bpf_msleep_interruptible(long timeout)
+ *	Description
+ *		Make the current task sleep until *timeout* milliseconds have
+ *		elapsed or until a signal is received.
+ *
+ *	Return
+ *		The remaining time of the sleep duration in milliseconds.
  */
 #define ___BPF_FUNC_MAPPER(FN, ctx...)			\
 	FN(unspec, 0, ##ctx)				\
@@ -6028,6 +6036,7 @@ union bpf_attr {
 	FN(user_ringbuf_drain, 209, ##ctx)		\
 	FN(cgrp_storage_get, 210, ##ctx)		\
 	FN(cgrp_storage_delete, 211, ##ctx)		\
+	FN(msleep_interruptible, 212, ##ctx)		\
 	/* This helper list is effectively frozen. If you are trying to	\
 	 * add a new helper, you should add a kfunc instead which has	\
 	 * less stability guarantees. See Documentation/bpf/kfuncs.rst	\
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index e3a2662f4e33..0a3449c282f2 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1905,6 +1905,19 @@ static const struct bpf_func_proto bpf_dynptr_data_proto = {
 	.arg3_type	= ARG_CONST_ALLOC_SIZE_OR_ZERO,
 };
 
+BPF_CALL_1(bpf_msleep_interruptible, long, timeout)
+{
+	return msleep_interruptible(timeout);
+}
+
+const struct bpf_func_proto bpf_msleep_interruptible_proto = {
+	.func		= bpf_msleep_interruptible,
+	.gpl_only	= false,
+	.might_sleep	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+};
+
 const struct bpf_func_proto bpf_get_current_task_proto __weak;
 const struct bpf_func_proto bpf_get_current_task_btf_proto __weak;
 const struct bpf_func_proto bpf_probe_read_user_proto __weak;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 52c432a44aeb..8a0b96aed0c0 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1475,6 +1475,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_get_branch_snapshot_proto;
 	case BPF_FUNC_find_vma:
 		return &bpf_find_vma_proto;
+	case BPF_FUNC_msleep_interruptible:
+		return &bpf_msleep_interruptible_proto;
 	default:
 		break;
 	}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 71d5ac83cf5d..cbbb6d70a7a3 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5814,6 +5814,14 @@ union bpf_attr {
  *		0 on success.
  *
  *		**-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ * long bpf_msleep_interruptible(long timeout)
+ *	Description
+ *		Make the current task sleep until *timeout* milliseconds have
+ *		elapsed or until a signal is received.
+ *
+ *	Return
+ *		The remaining time of the sleep duration in milliseconds.
  */
 #define ___BPF_FUNC_MAPPER(FN, ctx...)			\
 	FN(unspec, 0, ##ctx)				\
@@ -6028,6 +6036,7 @@ union bpf_attr {
 	FN(user_ringbuf_drain, 209, ##ctx)		\
 	FN(cgrp_storage_get, 210, ##ctx)		\
 	FN(cgrp_storage_delete, 211, ##ctx)		\
+	FN(msleep_interruptible, 212, ##ctx)		\
 	/* This helper list is effectively frozen. If you are trying to	\
 	 * add a new helper, you should add a kfunc instead which has	\
 	 * less stability guarantees. See Documentation/bpf/kfuncs.rst	\
-- 
2.49.0.906.g1f30a19c02-goog