Currenly only one bpf_ublk_queue_sqe() ebpf is added, ublksrv target
can use this helper to write ebpf prog to support ublk kernel & usersapce
zero copy, please see ublksrv test codes for more info.
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@xxxxxxxxxxxxxxxxx>
---
drivers/block/ublk_drv.c | 263 +++++++++++++++++++++++++++++++--
include/uapi/linux/bpf.h | 1 +
include/uapi/linux/ublk_cmd.h | 18 +++
kernel/bpf/verifier.c | 3 +-
scripts/bpf_doc.py | 4 +
tools/include/uapi/linux/bpf.h | 9 ++
6 files changed, 286 insertions(+), 12 deletions(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index b628e9eaefa6..d17ddb6fc27f 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -105,6 +105,12 @@ struct ublk_uring_cmd_pdu {
*/
#define UBLK_IO_FLAG_NEED_GET_DATA 0x08
+/*
+ * UBLK_IO_FLAG_BPF is set if IO command has be handled by ebpf prog instead
+ * of user space daemon.
+ */
+#define UBLK_IO_FLAG_BPF 0x10
+
struct ublk_io {
/* userspace buffer address from io cmd */
__u64 addr;
@@ -114,6 +120,11 @@ struct ublk_io {
struct io_uring_cmd *cmd;
};
+struct ublk_req_iter {
+ struct io_fixed_iter fixed_iter;
+ struct bio_vec *bvec;
+};
+
struct ublk_queue {
int q_id;
int q_depth;
@@ -163,6 +174,9 @@ struct ublk_device {
unsigned int nr_queues_ready;
atomic_t nr_aborted_queues;
+ struct bpf_prog *io_bpf_prog;
+ struct ublk_req_iter *iter_table;
+
/*
* Our ubq->daemon may be killed without any notification, so
* monitor each queue's daemon periodically
@@ -189,10 +203,48 @@ static DEFINE_MUTEX(ublk_ctl_mutex);
static struct miscdevice ublk_misc;
+struct ublk_io_bpf_ctx {
+ struct ublk_bpf_ctx ctx;
+ struct ublk_device *ub;
+};
+
+static inline struct ublk_req_iter *ublk_get_req_iter(struct ublk_device *ub,
+ int qid, int tag)
+{
+ return &(ub->iter_table[qid * ub->dev_info.queue_depth + tag]);
+}
+
+BPF_CALL_4(bpf_ublk_queue_sqe, struct ublk_io_bpf_ctx *, bpf_ctx,
+ struct io_uring_sqe *, sqe, u32, sqe_len, u32, fd)
+{
+ struct ublk_req_iter *req_iter;
+ u16 q_id = bpf_ctx->ctx.q_id;
+ u16 tag = bpf_ctx->ctx.tag;
+
+ req_iter = ublk_get_req_iter(bpf_ctx->ub, q_id, tag);
+ io_uring_submit_sqe(fd, sqe, sqe_len, &(req_iter->fixed_iter));
+ return 0;
+}
+
+const struct bpf_func_proto ublk_bpf_queue_sqe_proto = {
+ .func = bpf_ublk_queue_sqe,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_ANYTHING,
+ .arg2_type = ARG_ANYTHING,
+ .arg3_type = ARG_ANYTHING,
+ .arg4_type = ARG_ANYTHING,
+};
+
static const struct bpf_func_proto *
ublk_bpf_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
- return bpf_base_func_proto(func_id);
+ switch (func_id) {
+ case BPF_FUNC_ublk_queue_sqe:
+ return &ublk_bpf_queue_sqe_proto;
+ default:
+ return bpf_base_func_proto(func_id);
+ }
}
static bool ublk_bpf_is_valid_access(int off, int size,
@@ -200,6 +252,23 @@ static bool ublk_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 ublk_bpf_ctx))
+ return false;
+ if (off % size != 0)
+ return false;
+
+ switch (off) {
+ case offsetof(struct ublk_bpf_ctx, q_id):
+ return size == sizeof_field(struct ublk_bpf_ctx, q_id);
+ case offsetof(struct ublk_bpf_ctx, tag):
+ return size == sizeof_field(struct ublk_bpf_ctx, tag);
+ case offsetof(struct ublk_bpf_ctx, op):
+ return size == sizeof_field(struct ublk_bpf_ctx, op);
+ case offsetof(struct ublk_bpf_ctx, nr_sectors):
+ return size == sizeof_field(struct ublk_bpf_ctx, nr_sectors);
+ case offsetof(struct ublk_bpf_ctx, start_sector):
+ return size == sizeof_field(struct ublk_bpf_ctx, start_sector);
+ }
return false;
}
@@ -324,7 +393,7 @@ static void ublk_put_device(struct ublk_device *ub)
static inline struct ublk_queue *ublk_get_queue(struct ublk_device *dev,
int qid)
{
- return (struct ublk_queue *)&(dev->__queues[qid * dev->queue_size]);
+ return (struct ublk_queue *)&(dev->__queues[qid * dev->queue_size]);
}
static inline bool ublk_rq_has_data(const struct request *rq)
@@ -618,7 +687,6 @@ static void ublk_complete_rq(struct request *req)
{
struct ublk_queue *ubq = req->mq_hctx->driver_data;
struct ublk_io *io = &ubq->ios[req->tag];
- unsigned int unmapped_bytes;
/* failed read IO if nothing is read */
if (!io->res && req_op(req) == REQ_OP_READ)
@@ -641,15 +709,19 @@ static void ublk_complete_rq(struct request *req)
}
/* for READ request, writing data in iod->addr to rq buffers */
- unmapped_bytes = ublk_unmap_io(ubq, req, io);
+ if (likely(!(io->flags & UBLK_IO_FLAG_BPF))) {
+ unsigned int unmapped_bytes;
- /*
- * Extremely impossible since we got data filled in just before
- *
- * Re-read simply for this unlikely case.
- */
- if (unlikely(unmapped_bytes < io->res))
- io->res = unmapped_bytes;
+ unmapped_bytes = ublk_unmap_io(ubq, req, io);
+
+ /*
+ * Extremely impossible since we got data filled in just before
+ *
+ * Re-read simply for this unlikely case.
+ */
+ if (unlikely(unmapped_bytes < io->res))
+ io->res = unmapped_bytes;
+ }
if (blk_update_request(req, BLK_STS_OK, io->res))
blk_mq_requeue_request(req, true);
@@ -708,12 +780,92 @@ static inline void __ublk_abort_rq(struct ublk_queue *ubq,
mod_delayed_work(system_wq, &ubq->dev->monitor_work, 0);
}
+static int ublk_init_uring_fixed_iter(struct ublk_queue *ubq, struct request *rq)
+{
+ struct ublk_device *ub = ubq->dev;
+ struct bio *bio = rq->bio;
+ struct bio_vec *bvec;
+ struct req_iterator rq_iter;
+ struct bio_vec tmp;
+ int nr_bvec = 0;
+ struct ublk_req_iter *req_iter;
+ unsigned int rw, offset;
+
+ req_iter = ublk_get_req_iter(ub, ubq->q_id, rq->tag);
+ if (req_op(rq) == REQ_OP_READ)
+ rw = ITER_DEST;
+ else
+ rw = ITER_SOURCE;
+
+ rq_for_each_bvec(tmp, rq, rq_iter)
+ nr_bvec++;
+ if (rq->bio != rq->biotail) {
+ bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), GFP_NOIO);
+ if (!bvec)
+ return -EIO;
+ req_iter->bvec = bvec;
+
+ /*
+ * The bios of the request may be started from the middle of
+ * the 'bvec' because of bio splitting, so we can't directly
+ * copy bio->bi_iov_vec to new bvec. The rq_for_each_bvec
+ * API will take care of all details for us.
+ */
+ rq_for_each_bvec(tmp, rq, rq_iter) {
+ *bvec = tmp;
+ bvec++;
+ }
+ bvec = req_iter->bvec;
+ offset = 0;
+ } else {
+ /*
+ * Same here, this bio may be started from the middle of the
+ * 'bvec' because of bio splitting, so offset from the bvec
+ * must be passed to iov iterator
+ */
+ offset = bio->bi_iter.bi_bvec_done;
+ bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
+ req_iter->bvec = NULL;
+ }
+
+ iov_iter_bvec(&(req_iter->fixed_iter.iter), rw, bvec, nr_bvec, blk_rq_bytes(rq));
+ req_iter->fixed_iter.iter.iov_offset = offset;
+ return 0;
+}
+
+static int ublk_run_bpf_prog(struct ublk_queue *ubq, struct request *rq)
+{
+ int ret;
+ struct ublk_device *ub = ubq->dev;
+ struct ublk_io_bpf_ctx bpf_ctx;
+ u32 bpf_act;
+
+ if (!ub->io_bpf_prog)
+ return 0;
+
+ ret = ublk_init_uring_fixed_iter(ubq, rq);
+ if (ret < 0)
+ return UBLK_BPF_IO_ABORTED;
+
+ bpf_ctx.ub = ub;
+ bpf_ctx.ctx.q_id = ubq->q_id;
+ bpf_ctx.ctx.tag = rq->tag;
+ bpf_ctx.ctx.op = req_op(rq);
+ bpf_ctx.ctx.nr_sectors = blk_rq_sectors(rq);
+ bpf_ctx.ctx.start_sector = blk_rq_pos(rq);
+ bpf_act = bpf_prog_run_pin_on_cpu(ub->io_bpf_prog, &bpf_ctx);
+ return bpf_act;
+}
+
static inline void __ublk_rq_task_work(struct request *req)
{
struct ublk_queue *ubq = req->mq_hctx->driver_data;
+ struct ublk_device *ub = ubq->dev;
int tag = req->tag;
struct ublk_io *io = &ubq->ios[tag];
unsigned int mapped_bytes;
+ u32 bpf_act;
+ bool io_done = false;
pr_devel("%s: complete: op %d, qid %d tag %d io_flags %x addr %llx\n",
__func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags,
@@ -762,6 +914,10 @@ static inline void __ublk_rq_task_work(struct request *req)
ublk_get_iod(ubq, req->tag)->addr);
}
+ if (unlikely(ub->io_bpf_prog))
+ goto call_ebpf;
+
+normal_path:
mapped_bytes = ublk_map_io(ubq, req, io);
/* partially mapped, update io descriptor */
@@ -784,7 +940,21 @@ static inline void __ublk_rq_task_work(struct request *req)
mapped_bytes >> 9;
}
+ if (!io_done)
+ ubq_complete_io_cmd(io, UBLK_IO_RES_OK);
+ return;
+
+call_ebpf:
ubq_complete_io_cmd(io, UBLK_IO_RES_OK);
+ bpf_act = ublk_run_bpf_prog(ubq, req);
+ switch (bpf_act) {
+ case UBLK_BPF_IO_ABORTED:
+ case UBLK_BPF_IO_DROP:
+ case UBLK_BPF_IO_PASS:
+ io_done = true;
+ goto normal_path;
+ }
+ io->flags |= UBLK_IO_FLAG_BPF;
}
static inline void ublk_forward_io_cmds(struct ublk_queue *ubq)
@@ -1231,6 +1401,10 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
__func__, cmd->cmd_op, ub_cmd->q_id, tag,
ub_cmd->result);
+ /* To workaround task_work_add is not exported. */
+ if (unlikely(ub->io_bpf_prog && !(cmd->flags & IORING_URING_CMD_UNLOCK)))
+ goto out;
+
if (!(issue_flags & IO_URING_F_SQE128))
goto out;
@@ -1295,6 +1469,14 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
io->flags |= UBLK_IO_FLAG_ACTIVE;
io->cmd = cmd;
ublk_commit_completion(ub, ub_cmd);
+ if (io->flags & UBLK_IO_FLAG_BPF) {
+ struct ublk_req_iter *req_iter;
+
+ req_iter = ublk_get_req_iter(ub, ubq->q_id, tag);
+ io->flags &= ~UBLK_IO_FLAG_BPF;
+ kfree(req_iter->bvec);
+ req_iter->bvec = NULL;
+ }
break;
case UBLK_IO_NEED_GET_DATA:
if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
@@ -2009,6 +2191,59 @@ static int ublk_ctrl_end_recovery(struct io_uring_cmd *cmd)
return ret;
}
+static int ublk_ctrl_reg_bpf_prog(struct io_uring_cmd *cmd)
+{
+ struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+ struct ublk_device *ub;
+ struct bpf_prog *prog;
+ int ret = 0, nr_queues, depth;
+
+ ub = ublk_get_device_from_id(header->dev_id);
+ if (!ub)
+ return -EINVAL;
+
+ mutex_lock(&ub->mutex);
+ nr_queues = ub->dev_info.nr_hw_queues;
+ depth = ub->dev_info.queue_depth;
+ ub->iter_table = kzalloc(sizeof(struct ublk_req_iter) * depth * nr_queues,
+ GFP_KERNEL);
+ if (!ub->iter_table) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ prog = bpf_prog_get_type(header->data[0], BPF_PROG_TYPE_UBLK);
+ if (IS_ERR(prog)) {
+ kfree(ub->iter_table);
+ ret = PTR_ERR(prog);
+ goto out_unlock;
+ }
+ ub->io_bpf_prog = prog;
+
+out_unlock:
+ mutex_unlock(&ub->mutex);
+ ublk_put_device(ub);
+ return ret;
+}
+
+static int ublk_ctrl_unreg_bpf_prog(struct io_uring_cmd *cmd)
+{
+ struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+ struct ublk_device *ub;
+
+ ub = ublk_get_device_from_id(header->dev_id);
+ if (!ub)
+ return -EINVAL;
+
+ mutex_lock(&ub->mutex);
+ bpf_prog_put(ub->io_bpf_prog);
+ ub->io_bpf_prog = NULL;
+ kfree(ub->iter_table);
+ ub->iter_table = NULL;
+ mutex_unlock(&ub->mutex);
+ ublk_put_device(ub);
+ return 0;
+}
static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
@@ -2059,6 +2294,12 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
case UBLK_CMD_END_USER_RECOVERY:
ret = ublk_ctrl_end_recovery(cmd);
break;
+ case UBLK_CMD_REG_BPF_PROG:
+ ret = ublk_ctrl_reg_bpf_prog(cmd);
+ break;
+ case UBLK_CMD_UNREG_BPF_PROG:
+ ret = ublk_ctrl_unreg_bpf_prog(cmd);
+ break;
default:
break;
}
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 515b7b995b3a..578d65e9f30e 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5699,6 +5699,7 @@ union bpf_attr {
FN(user_ringbuf_drain, 209, ##ctx) \
FN(cgrp_storage_get, 210, ##ctx) \
FN(cgrp_storage_delete, 211, ##ctx) \
+ FN(ublk_queue_sqe, 212, ##ctx) \
/* */
/* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 8f88e3a29998..fbfe5145221e 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -17,6 +17,8 @@
#define UBLK_CMD_STOP_DEV 0x07
#define UBLK_CMD_SET_PARAMS 0x08
#define UBLK_CMD_GET_PARAMS 0x09
+#define UBLK_CMD_REG_BPF_PROG 0x0a
+#define UBLK_CMD_UNREG_BPF_PROG 0x0b
#define UBLK_CMD_START_USER_RECOVERY 0x10
#define UBLK_CMD_END_USER_RECOVERY 0x11
/*
@@ -230,4 +232,20 @@ struct ublk_params {
struct ublk_param_discard discard;
};
+struct ublk_bpf_ctx {
+ __u32 t_val;
+ __u16 q_id;
+ __u16 tag;
+ __u8 op;
+ __u32 nr_sectors;
+ __u64 start_sector;
+};
+
+enum {
+ UBLK_BPF_IO_ABORTED = 0,
+ UBLK_BPF_IO_DROP,
+ UBLK_BPF_IO_PASS,
+ UBLK_BPF_IO_REDIRECT,
+};
+
#endif
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1e5bc89aea36..b1645a3d93a2 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -24,6 +24,7 @@
#include <linux/bpf_lsm.h>
#include <linux/btf_ids.h>
#include <linux/poison.h>
+#include <linux/ublk_cmd.h>
#include "disasm.h"
@@ -12236,7 +12237,7 @@ static int check_return_code(struct bpf_verifier_env *env)
break;
case BPF_PROG_TYPE_UBLK:
- range = tnum_const(0);
+ range = tnum_range(UBLK_BPF_IO_ABORTED, UBLK_BPF_IO_REDIRECT);
break;
case BPF_PROG_TYPE_EXT:
diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py
index e8d90829f23e..f8672294e145 100755
--- a/scripts/bpf_doc.py
+++ b/scripts/bpf_doc.py
@@ -700,6 +700,8 @@ class PrinterHelpers(Printer):
'struct bpf_dynptr',
'struct iphdr',
'struct ipv6hdr',
+ 'struct ublk_io_bpf_ctx',
+ 'struct io_uring_sqe',
]
known_types = {
'...',
@@ -755,6 +757,8 @@ class PrinterHelpers(Printer):
'const struct bpf_dynptr',
'struct iphdr',
'struct ipv6hdr',
+ 'struct ublk_io_bpf_ctx',
+ 'struct io_uring_sqe',
}
mapped_types = {
'u8': '__u8',
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 515b7b995b3a..e3a81e576ec1 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5485,6 +5485,14 @@ union bpf_attr {
* 0 on success.
*
* **-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ *
+ * u64 bpf_ublk_queue_sqe(struct ublk_io_bpf_ctx *ctx, struct io_uring_sqe *sqe, u32 offset, u32 len)
+ * Description
+ * Submit ublk io requests.
+ * Return
+ * 0 on success.
+ *
*/
#define ___BPF_FUNC_MAPPER(FN, ctx...) \
FN(unspec, 0, ##ctx) \
@@ -5699,6 +5707,7 @@ union bpf_attr {
FN(user_ringbuf_drain, 209, ##ctx) \
FN(cgrp_storage_get, 210, ##ctx) \
FN(cgrp_storage_delete, 211, ##ctx) \
+ FN(ublk_queue_sqe, 212, ##ctx) \
/* */
/* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't
--
2.31.1
