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From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>
Cc: <andrii@kernel.org>, <kernel-team@fb.com>,
	Peter Zijlstra <peterz@infradead.org>, Yonghong Song <yhs@fb.com>
Subject: [PATCH v3 bpf-next 03/14] bpf: refactor perf_event_set_bpf_prog() to use struct bpf_prog input
Date: Thu, 29 Jul 2021 22:34:02 -0700	[thread overview]
Message-ID: <20210730053413.1090371-4-andrii@kernel.org> (raw)
In-Reply-To: <20210730053413.1090371-1-andrii@kernel.org>

Make internal perf_event_set_bpf_prog() use struct bpf_prog pointer as an
input argument, which makes it easier to re-use for other internal uses
(coming up for BPF link in the next patch). BPF program FD is not as
convenient and in some cases it's not available. So switch to struct bpf_prog,
move out refcounting outside and let caller do bpf_prog_put() in case of an
error. This follows the approach of most of the other BPF internal functions.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 kernel/events/core.c | 61 ++++++++++++++++++++------------------------
 1 file changed, 28 insertions(+), 33 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 464917096e73..bf4689403498 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5574,7 +5574,7 @@ static inline int perf_fget_light(int fd, struct fd *p)
 static int perf_event_set_output(struct perf_event *event,
 				 struct perf_event *output_event);
 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
-static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
+static int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog);
 static int perf_copy_attr(struct perf_event_attr __user *uattr,
 			  struct perf_event_attr *attr);
 
@@ -5637,7 +5637,22 @@ static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned lon
 		return perf_event_set_filter(event, (void __user *)arg);
 
 	case PERF_EVENT_IOC_SET_BPF:
-		return perf_event_set_bpf_prog(event, arg);
+	{
+		struct bpf_prog *prog;
+		int err;
+
+		prog = bpf_prog_get(arg);
+		if (IS_ERR(prog))
+			return PTR_ERR(prog);
+
+		err = perf_event_set_bpf_prog(event, prog);
+		if (err) {
+			bpf_prog_put(prog);
+			return err;
+		}
+
+		return 0;
+	}
 
 	case PERF_EVENT_IOC_PAUSE_OUTPUT: {
 		struct perf_buffer *rb;
@@ -9923,10 +9938,8 @@ static void bpf_overflow_handler(struct perf_event *event,
 	event->orig_overflow_handler(event, data, regs);
 }
 
-static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
+static int perf_event_set_bpf_handler(struct perf_event *event, struct bpf_prog *prog)
 {
-	struct bpf_prog *prog;
-
 	if (event->overflow_handler_context)
 		/* hw breakpoint or kernel counter */
 		return -EINVAL;
@@ -9934,9 +9947,8 @@ static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
 	if (event->prog)
 		return -EEXIST;
 
-	prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
-	if (IS_ERR(prog))
-		return PTR_ERR(prog);
+	if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
+		return -EINVAL;
 
 	if (event->attr.precise_ip &&
 	    prog->call_get_stack &&
@@ -9952,7 +9964,6 @@ static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
 		 * attached to perf_sample_data, do not allow attaching BPF
 		 * program that calls bpf_get_[stack|stackid].
 		 */
-		bpf_prog_put(prog);
 		return -EPROTO;
 	}
 
@@ -9974,7 +9985,7 @@ static void perf_event_free_bpf_handler(struct perf_event *event)
 	bpf_prog_put(prog);
 }
 #else
-static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
+static int perf_event_set_bpf_handler(struct perf_event *event, struct bpf_prog *prog)
 {
 	return -EOPNOTSUPP;
 }
@@ -10002,14 +10013,12 @@ static inline bool perf_event_is_tracing(struct perf_event *event)
 	return false;
 }
 
-static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
+static int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog)
 {
 	bool is_kprobe, is_tracepoint, is_syscall_tp;
-	struct bpf_prog *prog;
-	int ret;
 
 	if (!perf_event_is_tracing(event))
-		return perf_event_set_bpf_handler(event, prog_fd);
+		return perf_event_set_bpf_handler(event, prog);
 
 	is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
 	is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
@@ -10018,38 +10027,24 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
 		/* bpf programs can only be attached to u/kprobe or tracepoint */
 		return -EINVAL;
 
-	prog = bpf_prog_get(prog_fd);
-	if (IS_ERR(prog))
-		return PTR_ERR(prog);
-
 	if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
 	    (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
-	    (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
-		/* valid fd, but invalid bpf program type */
-		bpf_prog_put(prog);
+	    (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
 		return -EINVAL;
-	}
 
 	/* Kprobe override only works for kprobes, not uprobes. */
 	if (prog->kprobe_override &&
-	    !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
-		bpf_prog_put(prog);
+	    !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
 		return -EINVAL;
-	}
 
 	if (is_tracepoint || is_syscall_tp) {
 		int off = trace_event_get_offsets(event->tp_event);
 
-		if (prog->aux->max_ctx_offset > off) {
-			bpf_prog_put(prog);
+		if (prog->aux->max_ctx_offset > off)
 			return -EACCES;
-		}
 	}
 
-	ret = perf_event_attach_bpf_prog(event, prog);
-	if (ret)
-		bpf_prog_put(prog);
-	return ret;
+	return perf_event_attach_bpf_prog(event, prog);
 }
 
 static void perf_event_free_bpf_prog(struct perf_event *event)
@@ -10071,7 +10066,7 @@ static void perf_event_free_filter(struct perf_event *event)
 {
 }
 
-static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
+static int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog)
 {
 	return -ENOENT;
 }
-- 
2.30.2


  parent reply	other threads:[~2021-07-30  5:34 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30  5:33 [PATCH v3 bpf-next 00/14] BPF perf link and user-provided bpf_cookie Andrii Nakryiko
2021-07-30  5:34 ` [PATCH v3 bpf-next 01/14] bpf: refactor BPF_PROG_RUN into a function Andrii Nakryiko
2021-07-30 17:19   ` Yonghong Song
2021-08-09 22:43   ` Daniel Borkmann
2021-08-10  0:28     ` Andrii Nakryiko
2021-07-30  5:34 ` [PATCH v3 bpf-next 02/14] bpf: refactor BPF_PROG_RUN_ARRAY family of macros into functions Andrii Nakryiko
2021-08-09 23:00   ` Daniel Borkmann
2021-08-10  0:36     ` Andrii Nakryiko
2021-07-30  5:34 ` Andrii Nakryiko [this message]
2021-07-30  5:34 ` [PATCH v3 bpf-next 04/14] bpf: implement minimal BPF perf link Andrii Nakryiko
2021-07-30 17:24   ` Yonghong Song
2021-07-30  5:34 ` [PATCH v3 bpf-next 05/14] bpf: allow to specify user-provided bpf_cookie for BPF perf links Andrii Nakryiko
2021-07-30 22:02   ` Yonghong Song
2021-08-09 23:30   ` Daniel Borkmann
2021-08-10  0:52     ` Andrii Nakryiko
2021-07-30  5:34 ` [PATCH v3 bpf-next 06/14] bpf: add bpf_get_attach_cookie() BPF helper to access bpf_cookie value Andrii Nakryiko
2021-07-30 22:13   ` Yonghong Song
2021-07-30  5:34 ` [PATCH v3 bpf-next 07/14] libbpf: re-build libbpf.so when libbpf.map changes Andrii Nakryiko
2021-07-30 22:31   ` Yonghong Song
2021-07-30  5:34 ` [PATCH v3 bpf-next 08/14] libbpf: remove unused bpf_link's destroy operation, but add dealloc Andrii Nakryiko
2021-07-30  5:34 ` [PATCH v3 bpf-next 09/14] libbpf: use BPF perf link when supported by kernel Andrii Nakryiko
2021-07-30  5:34 ` [PATCH v3 bpf-next 10/14] libbpf: add bpf_cookie support to bpf_link_create() API Andrii Nakryiko
2021-07-30  5:34 ` [PATCH v3 bpf-next 11/14] libbpf: add bpf_cookie to perf_event, kprobe, uprobe, and tp attach APIs Andrii Nakryiko
2021-07-30  5:34 ` [PATCH v3 bpf-next 12/14] selftests/bpf: test low-level perf BPF link API Andrii Nakryiko
2021-07-30  5:34 ` [PATCH v3 bpf-next 13/14] selftests/bpf: extract uprobe-related helpers into trace_helpers.{c,h} Andrii Nakryiko
2021-07-30  5:34 ` [PATCH v3 bpf-next 14/14] selftests/bpf: add bpf_cookie selftests for high-level APIs Andrii Nakryiko
2021-08-01  5:11 ` [PATCH bpf-next v4] libbpf: introduce legacy kprobe events support Rafael David Tinoco
2021-08-06 22:29   ` Andrii Nakryiko
2021-09-12  6:48     ` [PATCH bpf-next v5] " Rafael David Tinoco
2021-09-12  6:52       ` Rafael David Tinoco
2021-09-14  4:44       ` Andrii Nakryiko
2021-09-14  5:02         ` Rafael David Tinoco
2021-09-14  5:21           ` Andrii Nakryiko
2021-09-14 14:27             ` sunyucong
2021-09-14 15:42               ` Rafael David Tinoco
2021-09-14 20:34                 ` [PATCH bpf-next] libbpf: fix build error introduced by legacy kprobe feature Rafael David Tinoco
2021-09-14 21:04                   ` Alexei Starovoitov
2021-09-14 21:35                 ` [PATCH bpf-next v2] " Rafael David Tinoco
2021-09-14 21:39                   ` Rafael David Tinoco
2021-09-14 21:48                     ` Andrii Nakryiko

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