@@ -15,6 +15,9 @@ io_uring_prep_close - prepare a file descriptor close request
.BI "
.BI "void io_uring_prep_close_direct(struct io_uring_sqe *" sqe ","
.BI " unsigned " file_index ");"
+.BI "
+.BI "void io_uring_prep_close_all(struct io_uring_sqe *" sqe ","
+.BI " int " fd ", unsigned " file_index ");"
.PP
.SH DESCRIPTION
.PP
@@ -32,6 +35,13 @@ argument instead of the
This is identical to unregistering the direct descriptor, and is provided as
a convenience.
+For a close request which also has a direct descriptor, the
+.BR io_uring_prep_close_all(3)
+function is identical to close file descriptor indicated by
+.I fd
+and unregister the direct descriptor specified by the
+.I file_index.
+
This function prepares an async
.BR close (2)
request. See that man page for details.
@@ -35,6 +35,16 @@ entry is updated and then removed from the table. This operation is equivalent t
first unregistering that entry and then inserting a new one, just bundled into
one combined operation.
+If
+.I offset
+is specified as IORING_FILE_INDEX_ALLOC, io_uring will allocate free direct
+descriptors instead of having the application to pass, and store allocated
+direct descriptors into
+.I fds
+array,
+.I cqe->res
+will return the number of direct descriptors allocated.
+
.SH RETURN VALUE
None
.SH ERRORS
@@ -614,6 +614,14 @@ static inline void io_uring_prep_close_direct(struct io_uring_sqe *sqe,
__io_uring_set_target_fixed_file(sqe, file_index);
}
+static inline void io_uring_prep_close_all(struct io_uring_sqe *sqe,
+ int fd, unsigned file_index)
+{
+ io_uring_prep_close(sqe, fd);
+ __io_uring_set_target_fixed_file(sqe, file_index);
+ sqe->close_flags = IORING_CLOSE_FD_AND_FILE_SLOT;
+}
+
static inline void io_uring_prep_read(struct io_uring_sqe *sqe, int fd,
void *buf, unsigned nbytes, __u64 offset)
{
@@ -50,6 +50,7 @@ struct io_uring_sqe {
__u32 unlink_flags;
__u32 hardlink_flags;
__u32 xattr_flags;
+ __u32 close_flags;
};
__u64 user_data; /* data to be passed back at completion time */
/* pack this to avoid bogus arm OABI complaints */
@@ -78,6 +79,11 @@ struct io_uring_sqe {
*/
#define IORING_FILE_INDEX_ALLOC (~0U)
+/*
+ * close flags, store in sqe->close_flags.
+ */
+#define IORING_CLOSE_FD_AND_FILE_SLOT (1U << 0)
+
enum {
IOSQE_FIXED_FILE_BIT,
IOSQE_IO_DRAIN_BIT,
@@ -79,6 +79,7 @@ test_srcs := \
files-exit-hang-poll.c \
files-exit-hang-timeout.c \
file-update.c \
+ file-update-index-alloc.c \
file-verify.c \
fixed-buf-iter.c \
fixed-link.c \
new file mode 100644
@@ -0,0 +1,139 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test IORING_OP_FILES_UPDATE can support io_uring
+ * allocates an available direct descriptor instead of having the
+ * application pass one.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/uio.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+int main(int argc, char *argv[])
+{
+ struct io_uring_cqe *cqe;
+ struct io_uring_sqe *sqe;
+ char wbuf[1] = { 0xef }, rbuf[1] = {0x0};
+ struct io_uring ring;
+ int i, ret, pipe_fds[2], fds[2] = { -1, -1};
+
+ ret = io_uring_queue_init(8, &ring, 0);
+ if (ret) {
+ fprintf(stderr, "ring setup failed\n");
+ return -1;
+ }
+
+ ret = io_uring_register_files(&ring, fds, 2);
+ if (ret) {
+ fprintf(stderr, "%s: register ret=%d\n", __func__, ret);
+ return -1;
+ }
+
+ if (pipe2(pipe_fds, O_NONBLOCK)) {
+ fprintf(stderr, "pipe() failed\n");
+ return -1;
+ }
+
+ /*
+ * Pass IORING_FILE_INDEX_ALLOC, so io_uring in kernel will allocate
+ * available direct descriptors.
+ */
+ fds[0] = pipe_fds[0];
+ fds[1] = pipe_fds[1];
+ sqe = io_uring_get_sqe(&ring);
+ io_uring_prep_files_update(sqe, fds, 2, IORING_FILE_INDEX_ALLOC);
+ ret = io_uring_submit(&ring);
+ if (ret != 1) {
+ fprintf(stderr, "sqe submit failed: %d\n", ret);
+ return -1;
+ }
+ ret = io_uring_wait_cqe(&ring, &cqe);
+ if (ret < 0) {
+ fprintf(stderr, "wait files update completion failed: %d\n", ret);
+ return ret;
+ }
+
+ if (cqe->res < 0) {
+ if (cqe->res == -EINVAL) {
+ fprintf(stdout, "files update(IORING_FILE_INDEX_ALLOC) not "
+ "supported, skipping\n");
+ return 0;
+ }
+ fprintf(stderr, "files update(IORING_FILE_INDEX_ALLOC) failed: %d\n", ret);
+ return ret;
+ }
+ ret = cqe->res;
+ if (ret != 2) {
+ fprintf(stderr, "should allocate 2 direct descriptors, but get:%d\n", ret);
+ return -1;
+ }
+ if (fds[0] != 0 || fds[1] != 1) {
+ fprintf(stderr, "allocate wrong direct descriptors:%d %d\n",
+ fds[0], fds[1]);
+ return -1;
+ }
+ io_uring_cqe_seen(&ring, cqe);
+
+ sqe = io_uring_get_sqe(&ring);
+ io_uring_prep_write(sqe, fds[1], wbuf, sizeof(wbuf), 0);
+ sqe->flags |= IOSQE_FIXED_FILE;
+ ret = io_uring_submit(&ring);
+ if (ret != 1) {
+ fprintf(stderr, "sqe submit failed: %d\n", ret);
+ return -1;
+ }
+ ret = io_uring_wait_cqe(&ring, &cqe);
+ if (ret < 0 || cqe->res < 0) {
+ fprintf(stderr, "write failed %d\n", ret);
+ return ret;
+ }
+ io_uring_cqe_seen(&ring, cqe);
+
+ sqe = io_uring_get_sqe(&ring);
+ io_uring_prep_read(sqe, fds[0], rbuf, sizeof(rbuf), 0);
+ sqe->flags |= IOSQE_FIXED_FILE;
+ ret = io_uring_submit(&ring);
+ if (ret != 1) {
+ fprintf(stderr, "sqe submit failed: %d\n", ret);
+ return -1;
+ }
+ ret = io_uring_wait_cqe(&ring, &cqe);
+ if (ret < 0 || cqe->res < 0) {
+ fprintf(stderr, "read failed %d\n", ret);
+ return ret;
+ }
+ if (rbuf[0] != (char)0xef) {
+ fprintf(stderr, "read wrong data %x\n", rbuf[0]);
+ return ret;
+ }
+ io_uring_cqe_seen(&ring, cqe);
+
+ sqe = io_uring_get_sqe(&ring);
+ io_uring_prep_close_all(sqe, pipe_fds[0], fds[0]);
+ sqe = io_uring_get_sqe(&ring);
+ io_uring_prep_close_all(sqe, pipe_fds[1], fds[1]);
+ ret = io_uring_submit(&ring);
+ if (ret != 2) {
+ fprintf(stderr, "sqe submit failed: %d\n", ret);
+ return -1;
+ }
+
+ for (i = 0; i < 2; i++) {
+ ret = io_uring_wait_cqe(&ring, &cqe);
+ if (ret < 0 || cqe->res < 0) {
+ fprintf(stderr, "wait close completion %d\n", ret);
+ return ret;
+ }
+ io_uring_cqe_seen(&ring, cqe);
+ }
+
+ io_uring_queue_exit(&ring);
+ return 0;
+}
Allocate available direct descriptors instead of having the application pass free fixed file slots. To use it, pass IORING_FILE_INDEX_ALLOC to io_uring_prep_files_update(), then io_uring in kernel will store picked fixed file slots in fd array and let cqe return the number of slots allocated. Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> --- V2: Update io_uring_prep_close(3) and io_uring_prep_files_update(3)'s man. Skip test in case old kernel does not support IORING_FILE_INDEX_ALLOC. --- man/io_uring_prep_close.3 | 10 +++ man/io_uring_prep_files_update.3 | 10 +++ src/include/liburing.h | 8 +++ src/include/liburing/io_uring.h | 6 ++ test/Makefile | 1 + test/file-update-index-alloc.c | 139 +++++++++++++++++++++++++++++++++++++++ 6 files changed, 174 insertions(+) create mode 100644 test/file-update-index-alloc.c