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From:   Pavel Begunkov <asml.silence@gmail.com>
To:     io-uring@vger.kernel.org, netdev@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Jens Axboe <axboe@kernel.dk>, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Horst Schirmeier <horst.schirmeier@tu-dortmund.de>,
        "Franz-B . Tuneke" <franz-bernhard.tuneke@tu-dortmund.de>,
        Christian Dietrich <stettberger@dokucode.de>
Subject: [PATCH 19/23] io_uring: pass user_data to bpf executor
Date:   Wed, 19 May 2021 15:13:30 +0100
Message-Id: <cb4d77ad3165084a9abddf72528c4721d7441888.1621424513.git.asml.silence@gmail.com>
In-Reply-To: <cover.1621424513.git.asml.silence@gmail.com>
References: <cover.1621424513.git.asml.silence@gmail.com>
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Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c                 | 16 ++++++++++++++++
 include/uapi/linux/io_uring.h |  4 ++++
 2 files changed, 20 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7c165b2ce8e4..c37846bca863 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -882,6 +882,7 @@ struct io_defer_entry {
 };
 
 struct io_bpf_ctx {
+	struct io_uring_bpf_ctx u;
 	struct io_ring_ctx	*ctx;
 };
 
@@ -10482,6 +10483,15 @@ static bool io_bpf_is_valid_access(int off, int size,
 				   const struct bpf_prog *prog,
 				   struct bpf_insn_access_aux *info)
 {
+	if (off < 0 || off >= sizeof(struct io_uring_bpf_ctx))
+		return false;
+	if (off % size != 0)
+		return false;
+
+	switch (off) {
+	case offsetof(struct io_uring_bpf_ctx, user_data):
+		return size == sizeof_field(struct io_uring_bpf_ctx, user_data);
+	}
 	return false;
 }
 
@@ -10505,6 +10515,8 @@ static void io_bpf_run(struct io_kiocb *req, unsigned int issue_flags)
 		     atomic_read(&req->task->io_uring->in_idle)))
 		goto done;
 
+	memset(&bpf_ctx.u, 0, sizeof(bpf_ctx.u));
+	bpf_ctx.u.user_data = req->user_data;
 	bpf_ctx.ctx = ctx;
 	prog = req->bpf.prog;
 
@@ -10591,6 +10603,10 @@ static int __init io_uring_init(void)
 	BUILD_BUG_SQE_ELEM(44, __s32,  splice_fd_in);
 	BUILD_BUG_SQE_ELEM(48, __u16,  cq_idx);
 
+	/* should be first, see io_bpf_is_valid_access() */
+	__BUILD_BUG_VERIFY_ELEMENT(struct io_bpf_ctx, 0,
+				   struct io_uring_bpf_ctx, u);
+
 	BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
 		     sizeof(struct io_uring_rsrc_update));
 	BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 25ab804670e1..d7b1713bcfb0 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -403,4 +403,8 @@ struct io_uring_getevents_arg {
 	__u64	ts;
 };
 
+struct io_uring_bpf_ctx {
+	__u64	user_data;
+};
+
 #endif
-- 
2.31.1