[bpf-next,3/5] bpf: Add bpf_run_ctx_type

Commit Message

Martin KaFai Lau Sept. 22, 2022, 10:56 p.m. UTC

From: Martin KaFai Lau <[e-mail]>

This patch adds a bpf_run_ctx_type to the struct bpf_run_ctx.
The next patch needs to look at the previous run ctx saved at
tramp_run_ctx->saved_run_ctx and checks if it is also
changing the tcp-cc for the same sk (saved in bpf_cookie).
Thus, it needs to know if the saved_run_ctx is the bpf_run_ctx
type that it is looking for before looking into its members.

Signed-off-by: Martin KaFai Lau <[e-mail]>
---
 include/linux/bpf.h      | 17 ++++++++++++++---
 kernel/bpf/bpf_iter.c    |  2 +-
 kernel/bpf/cgroup.c      |  2 +-
 kernel/bpf/trampoline.c  |  4 ++++
 kernel/trace/bpf_trace.c |  1 +
 net/bpf/test_run.c       |  2 +-
 6 files changed, 22 insertions(+), 6 deletions(-)

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 6fdbc1398b8a..902b1be047cf 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1517,7 +1517,18 @@  int bpf_prog_array_copy(struct bpf_prog_array *old_array,
 			u64 bpf_cookie,
 			struct bpf_prog_array **new_array);
 
-struct bpf_run_ctx {};
+enum bpf_run_ctx_type {
+	BPF_RUN_CTX_TYPE_NONE,
+	BPF_RUN_CTX_TYPE_CG,
+	BPF_RUN_CTX_TYPE_TRACE,
+	BPF_RUN_CTX_TYPE_TRAMP,
+	BPF_RUN_CTX_TYPE_KPROBE_MULTI,
+	BPF_RUN_CTX_TYPE_STRUCT_OPS,
+};
+
+struct bpf_run_ctx {
+	enum bpf_run_ctx_type type;
+};
 
 struct bpf_cg_run_ctx {
 	struct bpf_run_ctx run_ctx;
@@ -1568,7 +1579,7 @@  bpf_prog_run_array(const struct bpf_prog_array *array,
 	const struct bpf_prog_array_item *item;
 	const struct bpf_prog *prog;
 	struct bpf_run_ctx *old_run_ctx;
-	struct bpf_trace_run_ctx run_ctx;
+	struct bpf_trace_run_ctx run_ctx = { .run_ctx.type = BPF_RUN_CTX_TYPE_TRACE };
 	u32 ret = 1;
 
 	RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "no rcu lock held");
@@ -1607,7 +1618,7 @@  bpf_prog_run_array_sleepable(const struct bpf_prog_array __rcu *array_rcu,
 	const struct bpf_prog *prog;
 	const struct bpf_prog_array *array;
 	struct bpf_run_ctx *old_run_ctx;
-	struct bpf_trace_run_ctx run_ctx;
+	struct bpf_trace_run_ctx run_ctx = { .run_ctx.type = BPF_RUN_CTX_TYPE_TRACE };
 	u32 ret = 1;
 
 	might_fault();
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 5dc307bdeaeb..65ff0c93b0ba 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -694,7 +694,7 @@  struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop)
 
 int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx)
 {
-	struct bpf_run_ctx run_ctx, *old_run_ctx;
+	struct bpf_run_ctx run_ctx = {}, *old_run_ctx;
 	int ret;
 
 	if (prog->aux->sleepable) {
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 00c7f864900e..850fd6983b9a 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -37,7 +37,7 @@  bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
 	const struct bpf_prog *prog;
 	const struct bpf_prog_array *array;
 	struct bpf_run_ctx *old_run_ctx;
-	struct bpf_cg_run_ctx run_ctx;
+	struct bpf_cg_run_ctx run_ctx = { .run_ctx.type = BPF_RUN_CTX_TYPE_CG };
 	u32 func_ret;
 
 	run_ctx.retval = retval;
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index e6551e4a6064..313619012a59 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -882,6 +882,7 @@  u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct bpf_tramp_run_ctx *ru
 	rcu_read_lock();
 	migrate_disable();
 
+	run_ctx->run_ctx.type = BPF_RUN_CTX_TYPE_TRAMP;
 	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
 
 	if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) {
@@ -934,6 +935,7 @@  u64 notrace __bpf_prog_enter_lsm_cgroup(struct bpf_prog *prog,
 	rcu_read_lock();
 	migrate_disable();
 
+	run_ctx->run_ctx.type = BPF_RUN_CTX_TYPE_TRAMP;
 	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
 
 	return NO_START_TIME;
@@ -960,6 +962,7 @@  u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog, struct bpf_tramp_r
 		return 0;
 	}
 
+	run_ctx->run_ctx.type = BPF_RUN_CTX_TYPE_TRAMP;
 	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
 
 	return bpf_prog_start_time();
@@ -983,6 +986,7 @@  u64 notrace __bpf_prog_enter_struct_ops(struct bpf_prog *prog,
 	rcu_read_lock();
 	migrate_disable();
 
+	run_ctx->run_ctx.type = BPF_RUN_CTX_TYPE_STRUCT_OPS;
 	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
 
 	return bpf_prog_start_time();
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index b05f0310dbd3..7670ca88b721 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2575,6 +2575,7 @@  kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
 			   unsigned long entry_ip, struct pt_regs *regs)
 {
 	struct bpf_kprobe_multi_run_ctx run_ctx = {
+		.run_ctx.type = BPF_RUN_CTX_TYPE_KPROBE_MULTI,
 		.link = link,
 		.entry_ip = entry_ip,
 	};
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 13d578ce2a09..1f2a745e8641 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -374,7 +374,7 @@  static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat,
 {
 	struct bpf_prog_array_item item = {.prog = prog};
 	struct bpf_run_ctx *old_ctx;
-	struct bpf_cg_run_ctx run_ctx;
+	struct bpf_cg_run_ctx run_ctx = { .run_ctx.type = BPF_RUN_CTX_TYPE_CG };
 	struct bpf_test_timer t = { NO_MIGRATE };
 	enum bpf_cgroup_storage_type stype;
 	int ret;