[PATCH 3/3] io_uring: add splice(2) support

Pavel Begunkov
2020-01-22T00:06:18Z

Add support for splice(2). Nothing new, just reuse do_splice().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 86 +++++++++++++++++++++++++++++++++++
include/uapi/linux/io_uring.h | 16 ++++++-
2 files changed, 100 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e9e4aee0fb99..44ec9c63c41d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -74,6 +74,7 @@
#include <linux/namei.h>
#include <linux/fsnotify.h>
#include <linux/fadvise.h>
+#include <linux/splice.h>

#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
@@ -373,6 +374,15 @@ struct io_rw {
u64 len;
};

+struct io_splice {
+ struct file *file_in;
+ struct file *file_out;
+ loff_t __user *off_in;
+ loff_t __user *off_out;
+ u64 len;
+ unsigned int flags;
+};
+
struct io_connect {
struct file *file;
struct sockaddr __user *addr;
@@ -534,6 +544,7 @@ struct io_kiocb {
struct io_files_update files_update;
struct io_fadvise fadvise;
struct io_madvise madvise;
+ struct io_splice splice;
};

struct io_async_ctx *io;
@@ -719,6 +730,11 @@ static const struct io_op_def io_op_defs[] = {
.needs_file = 1,
.fd_non_neg = 1,
},
+ [IORING_OP_SPLICE] = {
+ .needs_file = 1,
+ .hash_reg_file = 1,
+ .unbound_nonreg_file = 1,
+ }
};

static void io_wq_submit_work(struct io_wq_work **workptr);
@@ -730,6 +746,10 @@ static void io_queue_linked_timeout(struct io_kiocb *req);
static int __io_sqe_files_update(struct io_ring_ctx *ctx,
struct io_uring_files_update *ip,
unsigned nr_args);
+static int io_get_file(struct io_submit_state *state,
+ struct io_ring_ctx *ctx,
+ int fd, struct file **out_file,
+ bool fixed);

static struct kmem_cache *req_cachep;

@@ -2322,6 +2342,61 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
return ret;
}

+static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+ struct io_splice* sp = &req->splice;
+
+ sp->file_out = NULL;
+ sp->off_in = u64_to_user_ptr(READ_ONCE(sqe->off));
+ sp->off_out = u64_to_user_ptr(READ_ONCE(sqe->off_out));
+ sp->len = READ_ONCE(sqe->splice_len);
+ sp->flags = READ_ONCE(sqe->splice_flags);
+
+ if (unlikely(READ_ONCE(sqe->ioprio) || (sp->flags & ~SPLICE_F_ALL)))
+ return -EINVAL;
+
+ return io_get_file(NULL, req->ctx, READ_ONCE(sqe->fd_out),
+ &sp->file_out, (sp->flags & IOSQE_SPLICE_FIXED_OUT));
+}
+
+static bool io_splice_punt(struct file *file)
+{
+ if (get_pipe_info(file))
+ return false;
+ if (!io_file_supports_async(file))
+ return true;
+ return !(file->f_mode & O_NONBLOCK);
+}
+
+static int io_splice(struct io_kiocb *req, struct io_kiocb **nxt,
+ 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;
+ long ret;
+
+ if (force_nonblock) {
+ if (io_splice_punt(in) || io_splice_punt(out)) {
+ req->flags |= REQ_F_MUST_PUNT;
+ return -EAGAIN;
+ }
+ flags |= SPLICE_F_NONBLOCK;
+ }
+
+ ret = do_splice(in, sp->off_in, out, sp->off_out, sp->len, flags);
+ if (force_nonblock && ret == -EAGAIN)
+ return -EAGAIN;
+
+ io_put_file(req->ctx, out, (flags & IOSQE_SPLICE_FIXED_OUT));
+ io_cqring_add_event(req, ret);
+ if (ret != sp->len)
+ req_set_fail_links(req);
+ io_put_req_find_next(req, nxt);
+ return 0;
+}
+
/*
* IORING_OP_NOP just posts a completion event, nothing else.
*/
@@ -4044,6 +4119,9 @@ static int io_req_defer_prep(struct io_kiocb *req,
case IORING_OP_OPENAT2:
ret = io_openat2_prep(req, sqe);
break;
+ case IORING_OP_SPLICE:
+ ret = io_splice_prep(req, sqe);
+ break;
default:
printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
req->opcode);
@@ -4272,6 +4350,14 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
}
ret = io_openat2(req, nxt, force_nonblock);
break;
+ case IORING_OP_SPLICE:
+ if (sqe) {
+ ret = io_splice_prep(req, sqe);
+ if (ret < 0)
+ break;
+ }
+ ret = io_splice(req, nxt, force_nonblock);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 57d05cc5e271..f234b13e7ed3 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -23,8 +23,14 @@ struct io_uring_sqe {
__u64 off; /* offset into file */
__u64 addr2;
};
- __u64 addr; /* pointer to buffer or iovecs */
- __u32 len; /* buffer size or number of iovecs */
+ union {
+ __u64 addr; /* pointer to buffer or iovecs */
+ __u64 off_out;
+ };
+ union {
+ __u32 len; /* buffer size or number of iovecs */
+ __s32 fd_out;
+ };
union {
__kernel_rwf_t rw_flags;
__u32 fsync_flags;
@@ -37,10 +43,12 @@ struct io_uring_sqe {
__u32 open_flags;
__u32 statx_flags;
__u32 fadvise_advice;
+ __u32 splice_flags;
};
__u64 user_data; /* data to be passed back at completion time */
union {
__u16 buf_index; /* index into fixed buffers, if used */
+ __u64 splice_len;
__u64 __pad2[3];
};
};
@@ -67,6 +75,9 @@ enum {
/* always go async */
#define IOSQE_ASYNC (1U << IOSQE_ASYNC_BIT)

+/* op custom flags */
+#define IOSQE_SPLICE_FIXED_OUT (1U << 16)
+
/*
* io_uring_setup() flags
*/
@@ -106,6 +117,7 @@ enum {
IORING_OP_SEND,
IORING_OP_RECV,
IORING_OP_OPENAT2,
+ IORING_OP_SPLICE,

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