[RFC PATCH 19/22] ublk: bpf: wire bpf aio with ublk io handling

[Ming Lei <tom.leiming@gmail.com>]

Add ublk_bpf_aio_prep_io_buf() and call it before running ublk bpf prog,
so wire everything together.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
 drivers/block/ublk/bpf.h     | 13 +++++++++
 drivers/block/ublk/bpf_ops.c | 51 +++++++++++++++++++++++++++++++++++-
 drivers/block/ublk/main.c    |  5 ----
 drivers/block/ublk/ublk.h    |  6 +++++
 4 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/drivers/block/ublk/bpf.h b/drivers/block/ublk/bpf.h
index 0ab25743ae7d..a3d238bc707d 100644
--- a/drivers/block/ublk/bpf.h
+++ b/drivers/block/ublk/bpf.h
@@ -99,6 +99,9 @@ static inline void ublk_bpf_io_dec_ref(struct ublk_bpf_io *io)
 				ubq->bpf_ops->release_io_cmd(io);
 		}
 
+		if (test_bit(UBLK_BPF_BVEC_ALLOCATED, &io->flags))
+			kvfree(io->buf.bvec);
+
 		if (test_bit(UBLK_BPF_IO_COMPLETED, &io->flags)) {
 			smp_rmb();
 			__clear_bit(UBLK_BPF_IO_PREP, &io->flags);
@@ -158,6 +161,11 @@ static inline queue_io_cmd_t ublk_get_bpf_any_io_cb(struct ublk_queue *ubq)
 	return ublk_get_bpf_io_cb_daemon(ubq);
 }
 
+static inline bool ublk_support_bpf_aio(const struct ublk_queue *ubq)
+{
+	return ublk_support_bpf(ubq) && ubq->bpf_aio_ops;
+}
+
 int ublk_bpf_init(void);
 int ublk_bpf_struct_ops_init(void);
 int ublk_bpf_prog_attach(struct bpf_prog_consumer *consumer);
@@ -190,6 +198,11 @@ static inline queue_io_cmd_t ublk_get_bpf_any_io_cb(struct ublk_queue *ubq)
 	return NULL;
 }
 
+static inline bool ublk_support_bpf_aio(const struct ublk_queue *ubq)
+{
+	return false;
+}
+
 static inline int ublk_bpf_init(void)
 {
 	return 0;
diff --git a/drivers/block/ublk/bpf_ops.c b/drivers/block/ublk/bpf_ops.c
index 05d8d415b30d..7085eab5e99b 100644
--- a/drivers/block/ublk/bpf_ops.c
+++ b/drivers/block/ublk/bpf_ops.c
@@ -155,6 +155,49 @@ void ublk_bpf_prog_detach(struct bpf_prog_consumer *consumer)
 	mutex_unlock(&ublk_bpf_ops_lock);
 }
 
+static int ublk_bpf_aio_prep_io_buf(const struct request *req)
+{
+	struct ublk_rq_data *data = blk_mq_rq_to_pdu((struct request *)req);
+	struct ublk_bpf_io *io = &data->bpf_data;
+	struct req_iterator rq_iter;
+	struct bio_vec *bvec;
+	struct bio_vec bv;
+	unsigned offset;
+
+	io->buf.bvec = NULL;
+	io->buf.nr_bvec = 0;
+
+	if (!ublk_rq_has_data(req))
+		return 0;
+
+	rq_for_each_bvec(bv, req, rq_iter)
+		io->buf.nr_bvec++;
+
+	if (!io->buf.nr_bvec)
+		return 0;
+
+	if (req->bio != req->biotail) {
+		int idx = 0;
+
+		bvec = kvmalloc_array(io->buf.nr_bvec, sizeof(struct bio_vec),
+				GFP_NOIO);
+		if (!bvec)
+			return -ENOMEM;
+
+		offset = 0;
+		rq_for_each_bvec(bv, req, rq_iter)
+			bvec[idx++] = bv;
+		__set_bit(UBLK_BPF_BVEC_ALLOCATED, &io->flags);
+	} else {
+		struct bio *bio = req->bio;
+
+		offset = bio->bi_iter.bi_bvec_done;
+		bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
+	}
+	io->buf.bvec = bvec;
+	io->buf.bvec_off = offset;
+	return 0;
+}
 
 static void ublk_bpf_prep_io(struct ublk_bpf_io *io,
 		const struct ublksrv_io_desc *iod)
@@ -180,8 +223,14 @@ bool ublk_run_bpf_handler(struct ublk_queue *ubq, struct request *req,
 	bool res = true;
 	int err;
 
-	if (!test_bit(UBLK_BPF_IO_PREP, &bpf_io->flags))
+	if (!test_bit(UBLK_BPF_IO_PREP, &bpf_io->flags)) {
 		ublk_bpf_prep_io(bpf_io, iod);
+		if (ublk_support_bpf_aio(ubq)) {
+			err = ublk_bpf_aio_prep_io_buf(req);
+			if (err)
+				goto fail;
+		}
+	}
 
 	do {
 		enum ublk_bpf_disposition rc;
diff --git a/drivers/block/ublk/main.c b/drivers/block/ublk/main.c
index 3c2ed9bf924d..1974ebd33ce0 100644
--- a/drivers/block/ublk/main.c
+++ b/drivers/block/ublk/main.c
@@ -512,11 +512,6 @@ void ublk_put_device(struct ublk_device *ub)
 	put_device(&ub->cdev_dev);
 }
 
-static inline bool ublk_rq_has_data(const struct request *rq)
-{
-	return bio_has_data(rq->bio);
-}
-
 static inline char *ublk_queue_cmd_buf(struct ublk_device *ub, int q_id)
 {
 	return ublk_get_queue(ub, q_id)->io_cmd_buf;
diff --git a/drivers/block/ublk/ublk.h b/drivers/block/ublk/ublk.h
index 4bd04512c894..00b09589d95c 100644
--- a/drivers/block/ublk/ublk.h
+++ b/drivers/block/ublk/ublk.h
@@ -41,6 +41,7 @@
 enum {
 	UBLK_BPF_IO_PREP	= 0,
 	UBLK_BPF_IO_COMPLETED   = 1,
+	UBLK_BPF_BVEC_ALLOCATED	= 2,
 };
 
 struct ublk_bpf_io {
@@ -215,6 +216,11 @@ static inline bool ublk_dev_support_bpf_aio(const struct ublk_device *ub)
 	return ub->params.bpf.flags & UBLK_BPF_HAS_AIO_OPS_ID;
 }
 
+static inline bool ublk_rq_has_data(const struct request *rq)
+{
+	return bio_has_data(rq->bio);
+}
+
 struct ublk_device *ublk_get_device(struct ublk_device *ub);
 struct ublk_device *ublk_get_device_from_id(int idx);
 void ublk_put_device(struct ublk_device *ub);
-- 
2.47.0