[PATCH v2 0/2] splice helpers + tests

[PATCH v2 0/2] splice helpers + tests

[Pavel Begunkov]

Add splice prep helpers and some basic tests.

v2: minor: fix comment, add inline, remove newline

Pavel Begunkov (2):
  splice: add splice(2) helpers
  test/splice: add basic splice tests

 src/include/liburing.h          |  11 +++
 src/include/liburing/io_uring.h |  14 +++-
 test/Makefile                   |   4 +-
 test/splice.c                   | 138 ++++++++++++++++++++++++++++++++
 4 files changed, 164 insertions(+), 3 deletions(-)
 create mode 100644 test/splice.c

-- 
2.24.0

[PATCH v2 1/2] splice: add splice(2) helpers

[Pavel Begunkov]

Add splice helpers and update io_uring.h

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 src/include/liburing.h          | 11 +++++++++++
 src/include/liburing/io_uring.h | 14 +++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/include/liburing.h b/src/include/liburing.h
index 8ca6cd9..9ff2a54 100644
--- a/src/include/liburing.h
+++ b/src/include/liburing.h
@@ -191,6 +191,17 @@ static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
 	sqe->__pad2[0] = sqe->__pad2[1] = sqe->__pad2[2] = 0;
 }
 
+static inline void io_uring_prep_splice(struct io_uring_sqe *sqe,
+					int fd_in, loff_t off_in,
+					int fd_out, loff_t off_out,
+					unsigned int nbytes, int splice_flags)
+{
+	io_uring_prep_rw(IORING_OP_SPLICE, sqe, fd_out, (void *)off_in,
+			 nbytes, off_out);
+	sqe->splice_fd_in = fd_in;
+	sqe->splice_flags = splice_flags;
+}
+
 static inline void io_uring_prep_readv(struct io_uring_sqe *sqe, int fd,
 				       const struct iovec *iovecs,
 				       unsigned nr_vecs, off_t offset)
diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
index 424fb4b..dc78697 100644
--- a/src/include/liburing/io_uring.h
+++ b/src/include/liburing/io_uring.h
@@ -23,7 +23,10 @@ struct io_uring_sqe {
 		__u64	off;	/* offset into file */
 		__u64	addr2;
 	};
-	__u64	addr;		/* pointer to buffer or iovecs */
+	union {
+		__u64	addr;	/* pointer to buffer or iovecs */
+		__u64	off_in;
+	};
 	__u32	len;		/* buffer size or number of iovecs */
 	union {
 		__kernel_rwf_t	rw_flags;
@@ -37,6 +40,7 @@ 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 {
@@ -45,6 +49,7 @@ struct io_uring_sqe {
 			__u16	buf_index;
 			/* personality to use, if used */
 			__u16	personality;
+			__u32	splice_fd_in;
 		};
 		__u64	__pad2[3];
 	};
@@ -113,6 +118,7 @@ enum {
 	IORING_OP_RECV,
 	IORING_OP_OPENAT2,
 	IORING_OP_EPOLL_CTL,
+	IORING_OP_SPLICE,
 
 	/* this goes last, obviously */
 	IORING_OP_LAST,
@@ -128,6 +134,12 @@ enum {
  */
 #define IORING_TIMEOUT_ABS	(1U << 0)
 
+/*
+ * sqe->splice_flags
+ * extends splice(2) flags
+ */
+#define SPLICE_F_FD_IN_FIXED	(1U << 31) /* the last bit of __u32 */
+
 /*
  * IO completion data structure (Completion Queue Entry)
  */
-- 
2.24.0

[PATCH v2 2/2] test/splice: add basic splice tests

[Pavel Begunkov]

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 test/Makefile |   4 +-
 test/splice.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 140 insertions(+), 2 deletions(-)
 create mode 100644 test/splice.c

diff --git a/test/Makefile b/test/Makefile
index cf91011..94bbd18 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -20,7 +20,7 @@ all_targets += poll poll-cancel ring-leak fsync io_uring_setup io_uring_register
 		connect 7ad0e4b2f83c-test submit-reuse fallocate open-close \
 		file-update statx accept-reuse poll-v-poll fadvise madvise \
 		short-read openat2 probe shared-wq personality eventfd \
-		send_recv eventfd-ring across-fork
+		send_recv eventfd-ring across-fork splice
 
 include ../Makefile.quiet
 
@@ -47,7 +47,7 @@ test_srcs := poll.c poll-cancel.c ring-leak.c fsync.c io_uring_setup.c \
 	7ad0e4b2f83c-test.c submit-reuse.c fallocate.c open-close.c \
 	file-update.c statx.c accept-reuse.c poll-v-poll.c fadvise.c \
 	madvise.c short-read.c openat2.c probe.c shared-wq.c \
-	personality.c eventfd.c eventfd-ring.c across-fork.c
+	personality.c eventfd.c eventfd-ring.c across-fork.c splice.c
 
 test_objs := $(patsubst %.c,%.ol,$(test_srcs))
 
diff --git a/test/splice.c b/test/splice.c
new file mode 100644
index 0000000..92b3195
--- /dev/null
+++ b/test/splice.c
@@ -0,0 +1,138 @@
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#include "liburing.h"
+
+static int copy_single(struct io_uring *ring,
+			int fd_in, loff_t off_in,
+			int fd_out, loff_t off_out,
+			unsigned int len,
+			unsigned flags1, unsigned flags2)
+{
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	int ret, i, err = -1;
+	int pipe_fds[2] = {-1, -1};
+
+	if (pipe(pipe_fds) < 0)
+		goto exit;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		printf("get sqe failed\n");
+		goto exit;
+	}
+	io_uring_prep_splice(sqe, fd_in, off_in, pipe_fds[1], -1,
+			     len, flags1);
+	sqe->user_data = 1;
+	sqe->flags = IOSQE_IO_LINK;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		printf("get sqe failed\n");
+		goto exit;
+	}
+	io_uring_prep_splice(sqe, pipe_fds[0], -1, fd_out, off_out,
+			     len, flags2);
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		printf("sqe submit failed: %d\n", ret);
+		goto exit;
+	}
+
+	for (i = 0; i < 2; i++) {
+		ret = io_uring_wait_cqe(ring, &cqe);
+		if (ret < 0 || cqe->res != len) {
+			printf("wait completion %d\n", cqe->res);
+			goto exit;
+		}
+		io_uring_cqe_seen(ring, cqe);
+	}
+	err = 0;
+exit:
+	if (pipe_fds[0] >= 0) {
+		close(pipe_fds[0]);
+		close(pipe_fds[1]);
+	}
+	return err;
+}
+
+static int test_splice(struct io_uring *ring)
+{
+	int ret, err = 1;
+	int len = 4 * 4096;
+	int fd_out = -1, fd_in = -1;
+	int fd_in_idx;
+
+	fd_in = open("/dev/urandom", O_RDONLY);
+	if (fd_in < 0)
+		goto exit;
+	fd_out = memfd_create("splice_test_out_file", 0);
+	if (fd_out < 0)
+		goto exit;
+	if (ftruncate(fd_out, len) == -1)
+		goto exit;
+
+	ret = copy_single(ring, fd_in, -1, fd_out, -1, len,
+			  SPLICE_F_MOVE | SPLICE_F_MORE, 0);
+	if (ret) {
+		printf("basic splice-copy failed\n");
+		goto exit;
+	}
+
+	ret = copy_single(ring, fd_in, 0, fd_out, 0, len,
+			  0, SPLICE_F_MOVE | SPLICE_F_MORE);
+	if (ret) {
+		printf("basic splice with offset failed\n");
+		goto exit;
+	}
+
+	fd_in_idx = 0;
+	ret = io_uring_register_files(ring, &fd_in, 1);
+	if (ret) {
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto exit;
+	}
+
+	ret = copy_single(ring, fd_in_idx, 0, fd_out, 0, len,
+			  SPLICE_F_FD_IN_FIXED, 0);
+	if (ret) {
+		printf("basic splice with reg files failed\n");
+		goto exit;
+	}
+
+	err = 0;
+exit:
+	if (fd_out >= 0)
+		close(fd_out);
+	if (fd_in >= 0)
+		close(fd_in);
+	return err;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int ret;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		printf("ring setup failed\n");
+		return 1;
+	}
+
+	ret = test_splice(&ring);
+	if (ret) {
+		printf("test_splice failed %i %i\n", ret, errno);
+		return ret;
+	}
+
+	return 0;
+}
-- 
2.24.0

Re: [PATCH v2 1/2] splice: add splice(2) helpers

[Stefan Metzmacher]

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Hi Pavel,

> diff --git a/src/include/liburing.h b/src/include/liburing.h
> index 8ca6cd9..9ff2a54 100644
> --- a/src/include/liburing.h
> +++ b/src/include/liburing.h
> @@ -191,6 +191,17 @@ static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
>  	sqe->__pad2[0] = sqe->__pad2[1] = sqe->__pad2[2] = 0;
>  }
>  
> +static inline void io_uring_prep_splice(struct io_uring_sqe *sqe,
> +					int fd_in, loff_t off_in,
> +					int fd_out, loff_t off_out,
> +					unsigned int nbytes, int splice_flags)
> +{

The splice() syscall takes 'size_t len' and 'unsigned int flags',
I think we should at least change this to 'unsigned int splice_flags'.

> diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
> index 424fb4b..dc78697 100644
> --- a/src/include/liburing/io_uring.h
> +++ b/src/include/liburing/io_uring.h
> @@ -23,7 +23,10 @@ struct io_uring_sqe {
>  		__u64	off;	/* offset into file */
>  		__u64	addr2;
>  	};
> -	__u64	addr;		/* pointer to buffer or iovecs */
> +	union {
> +		__u64	addr;	/* pointer to buffer or iovecs */
> +		__u64	off_in;
> +	};
>  	__u32	len;		/* buffer size or number of iovecs */
>  	union {
>  		__kernel_rwf_t	rw_flags;
> @@ -37,6 +40,7 @@ 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 {
> @@ -45,6 +49,7 @@ struct io_uring_sqe {
>  			__u16	buf_index;
>  			/* personality to use, if used */
>  			__u16	personality;
> +			__u32	splice_fd_in;

Shouldn't this be __s32 in order to match "__s32 fd"?

>  		};

Can you please add BUILD_BUG_SQE_ELEM() checks for the new elements
in io_uring_init()?

Thanks!
metze


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Re: [PATCH v2 1/2] splice: add splice(2) helpers

[Pavel Begunkov]

On 2/17/2020 6:48 PM, Stefan Metzmacher wrote:
> Hi Pavel,
> 
>> diff --git a/src/include/liburing.h b/src/include/liburing.h
>> index 8ca6cd9..9ff2a54 100644
>> --- a/src/include/liburing.h
>> +++ b/src/include/liburing.h
>> @@ -191,6 +191,17 @@ static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
>>  	sqe->__pad2[0] = sqe->__pad2[1] = sqe->__pad2[2] = 0;
>>  }
>>  
>> +static inline void io_uring_prep_splice(struct io_uring_sqe *sqe,
>> +					int fd_in, loff_t off_in,
>> +					int fd_out, loff_t off_out,
>> +					unsigned int nbytes, int splice_flags)
>> +{
> 
> The splice() syscall takes 'size_t len' and 'unsigned int flags',

sqe->len is u32, so can't fit size_t there, it was discussed before.

> I think we should at least change this to 'unsigned int splice_flags'.
> 

Good point, for the comments below as well. I'll resend.

>> diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
>> index 424fb4b..dc78697 100644
>> --- a/src/include/liburing/io_uring.h
>> +++ b/src/include/liburing/io_uring.h
>> @@ -23,7 +23,10 @@ struct io_uring_sqe {
>>  		__u64	off;	/* offset into file */
>>  		__u64	addr2;
>>  	};
>> -	__u64	addr;		/* pointer to buffer or iovecs */
>> +	union {
>> +		__u64	addr;	/* pointer to buffer or iovecs */
>> +		__u64	off_in;
>> +	};
>>  	__u32	len;		/* buffer size or number of iovecs */
>>  	union {
>>  		__kernel_rwf_t	rw_flags;
>> @@ -37,6 +40,7 @@ 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 {
>> @@ -45,6 +49,7 @@ struct io_uring_sqe {
>>  			__u16	buf_index;
>>  			/* personality to use, if used */
>>  			__u16	personality;
>> +			__u32	splice_fd_in;
> 
> Shouldn't this be __s32 in order to match "__s32 fd"?
> 
>>  		};
> 
> Can you please add BUILD_BUG_SQE_ELEM() checks for the new elements
> in io_uring_init()?
> 
> Thanks!
> metze
> 

-- 
Pavel Begunkov