[PATCH 2/2] io_uring: add tee(2) support

Pavel Begunkov
2020-05-02T12:10:45Z

Add IORING_OP_TEE implementing tee(2) support. Almost identical to
splice bits, but without offsets.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 64 +++++++++++++++++++++++++++++++++--
include/uapi/linux/io_uring.h | 1 +
2 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4ed82d39540b..dc314f66fbc9 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -855,6 +855,11 @@ static const struct io_op_def io_op_defs[] = {
},
[IORING_OP_PROVIDE_BUFFERS] = {},
[IORING_OP_REMOVE_BUFFERS] = {},
+ [IORING_OP_TEE] = {
+ .needs_file = 1,
+ .hash_reg_file = 1,
+ .unbound_nonreg_file = 1,
+ },
};

static void io_wq_submit_work(struct io_wq_work **workptr);
@@ -2754,7 +2759,8 @@ static int io_write(struct io_kiocb *req, bool force_nonblock)
return ret;
}

-static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+static int __io_splice_prep(struct io_kiocb *req,
+ const struct io_uring_sqe *sqe)
{
struct io_splice* sp = &req->splice;
unsigned int valid_flags = SPLICE_F_FD_IN_FIXED | SPLICE_F_ALL;
@@ -2764,8 +2770,6 @@ static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return 0;

sp->file_in = NULL;
- sp->off_in = READ_ONCE(sqe->splice_off_in);
- sp->off_out = READ_ONCE(sqe->off);
sp->len = READ_ONCE(sqe->len);
sp->flags = READ_ONCE(sqe->splice_flags);

@@ -2784,6 +2788,48 @@ static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return 0;
}

+static int io_tee_prep(struct io_kiocb *req,
+ const struct io_uring_sqe *sqe)
+{
+ if (READ_ONCE(sqe->splice_off_in) || READ_ONCE(sqe->off))
+ return -EINVAL;
+ return __io_splice_prep(req, sqe);
+}
+
+static int io_tee(struct io_kiocb *req, bool force_nonblock)
+{
+ struct io_splice *sp = &req->splice;
+ struct file *in = sp->file_in;
+ struct file *out = sp->file_out;
+ unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
+ long ret;
+
+ if (force_nonblock)
+ return -EAGAIN;
+
+ ret = do_tee(in, out, sp->len, flags);
+ if (force_nonblock && ret == -EAGAIN)
+ return -EAGAIN;
+
+ io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED));
+ req->flags &= ~REQ_F_NEED_CLEANUP;
+
+ io_cqring_add_event(req, ret);
+ if (ret != sp->len)
+ req_set_fail_links(req);
+ io_put_req(req);
+ return 0;
+}
+
+static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+ struct io_splice* sp = &req->splice;
+
+ sp->off_in = READ_ONCE(sqe->splice_off_in);
+ sp->off_out = READ_ONCE(sqe->off);
+ return __io_splice_prep(req, sqe);
+}
+
static int io_splice(struct io_kiocb *req, bool force_nonblock)
{
struct io_splice *sp = &req->splice;
@@ -4978,6 +5024,9 @@ static int io_req_defer_prep(struct io_kiocb *req,
case IORING_OP_REMOVE_BUFFERS:
ret = io_remove_buffers_prep(req, sqe);
break;
+ case IORING_OP_TEE:
+ ret = io_tee_prep(req, sqe);
+ break;
default:
printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
req->opcode);
@@ -5051,6 +5100,7 @@ static void io_cleanup_req(struct io_kiocb *req)
putname(req->open.filename);
break;
case IORING_OP_SPLICE:
+ case IORING_OP_TEE:
io_put_file(req, req->splice.file_in,
(req->splice.flags & SPLICE_F_FD_IN_FIXED));
break;
@@ -5281,6 +5331,14 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
}
ret = io_remove_buffers(req, force_nonblock);
break;
+ case IORING_OP_TEE:
+ if (sqe) {
+ ret = io_tee_prep(req, sqe);
+ if (ret < 0)
+ break;
+ }
+ ret = io_tee(req, force_nonblock);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index e48d746b8e2a..a279151437fc 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -129,6 +129,7 @@ enum {
IORING_OP_SPLICE,
IORING_OP_PROVIDE_BUFFERS,
IORING_OP_REMOVE_BUFFERS,
+ IORING_OP_TEE,

/* this goes last, obviously */
IORING_OP_LAST,
--
2.24.0