This series is based on top of a new IORING_CQ_EVENTFD_DISABLED
flag available in the CQ ring flags.
I added io_uring_cq_eventfd_enabled() to get the status of eventfd
notifications, and io_uring_cq_eventfd_toggle() to disable/enabled
eventfd notifications.
I updated man pages and I added a eventfd-disable.c test case.
v1 -> v2:
- renamed io_uring_cq_eventfd_toggle()
- return EOPNOTSUPP only if we need to change the flag
Stefano Garzarella (5):
Add CQ ring 'flags' field
man/io_uring_setup.2: add 'flags' field in the struct
io_cqring_offsets
Add helpers to set and get eventfd notification status
man/io_uring_register.2: add IORING_CQ_EVENTFD_DISABLED description
Add test/eventfd-disable.c test case
.gitignore | 1 +
man/io_uring_register.2 | 8 ++
man/io_uring_setup.2 | 3 +-
src/include/liburing.h | 34 ++++++++
src/include/liburing/io_uring.h | 11 ++-
src/setup.c | 2 +
test/Makefile | 6 +-
test/eventfd-disable.c | 148 ++++++++++++++++++++++++++++++++
8 files changed, 209 insertions(+), 4 deletions(-)
create mode 100644 test/eventfd-disable.c
--
2.25.4
This new test checks if the mechanism to enable/disable notifications
through eventfd when a request is completed works correctly.
Signed-off-by: Stefano Garzarella <[email protected]>
---
v1 -> v2:
- renamed io_uring_cq_eventfd_toggle()
---
.gitignore | 1 +
test/Makefile | 6 +-
test/eventfd-disable.c | 148 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 153 insertions(+), 2 deletions(-)
create mode 100644 test/eventfd-disable.c
diff --git a/.gitignore b/.gitignore
index 19c47d9..fee76e8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -40,6 +40,7 @@
/test/defer
/test/eeed8b54e0df-test
/test/eventfd
+/test/eventfd-disable
/test/eventfd-ring
/test/fadvise
/test/fallocate
diff --git a/test/Makefile b/test/Makefile
index 61825d1..7df550d 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -21,7 +21,8 @@ all_targets += poll poll-cancel ring-leak fsync io_uring_setup io_uring_register
file-update accept-reuse poll-v-poll fadvise madvise \
short-read openat2 probe shared-wq personality eventfd \
send_recv eventfd-ring across-fork sq-poll-kthread splice \
- lfs-openat lfs-openat-write iopoll d4ae271dfaae-test
+ lfs-openat lfs-openat-write iopoll d4ae271dfaae-test \
+ eventfd-disable
include ../Makefile.quiet
@@ -53,7 +54,8 @@ test_srcs := poll.c poll-cancel.c ring-leak.c fsync.c io_uring_setup.c \
file-update.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 sq-poll-kthread.c \
- splice.c lfs-openat.c lfs-openat-write.c iopoll.c d4ae271dfaae-test.c
+ splice.c lfs-openat.c lfs-openat-write.c iopoll.c d4ae271dfaae-test.c \
+ eventfd-disable.c
ifdef CONFIG_HAVE_STATX
test_srcs += statx.c
diff --git a/test/eventfd-disable.c b/test/eventfd-disable.c
new file mode 100644
index 0000000..ad086d4
--- /dev/null
+++ b/test/eventfd-disable.c
@@ -0,0 +1,148 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test disable/enable notifications through eventfd
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/poll.h>
+#include <sys/eventfd.h>
+
+#include "liburing.h"
+
+int main(int argc, char *argv[])
+{
+ struct io_uring_params p = {};
+ struct io_uring_sqe *sqe;
+ struct io_uring_cqe *cqe;
+ struct io_uring ring;
+ uint64_t ptr;
+ struct iovec vec = {
+ .iov_base = &ptr,
+ .iov_len = sizeof(ptr)
+ };
+ int ret, evfd, i;
+
+ ret = io_uring_queue_init_params(64, &ring, &p);
+ if (ret) {
+ fprintf(stderr, "ring setup failed: %d\n", ret);
+ return 1;
+ }
+
+ evfd = eventfd(0, EFD_CLOEXEC);
+ if (evfd < 0) {
+ perror("eventfd");
+ return 1;
+ }
+
+ ret = io_uring_register_eventfd(&ring, evfd);
+ if (ret) {
+ fprintf(stderr, "failed to register evfd: %d\n", ret);
+ return 1;
+ }
+
+ if (!io_uring_cq_eventfd_enabled(&ring)) {
+ fprintf(stderr, "eventfd disabled\n");
+ return 1;
+ }
+
+ ret = io_uring_cq_eventfd_toggle(&ring, false);
+ if (ret) {
+ fprintf(stdout, "Skipping, CQ flags not available!\n");
+ return 0;
+ }
+
+ sqe = io_uring_get_sqe(&ring);
+ io_uring_prep_readv(sqe, evfd, &vec, 1, 0);
+ sqe->user_data = 1;
+
+ ret = io_uring_submit(&ring);
+ if (ret != 1) {
+ fprintf(stderr, "submit: %d\n", ret);
+ return 1;
+ }
+
+ for (i = 0; i < 63; i++) {
+ sqe = io_uring_get_sqe(&ring);
+ io_uring_prep_nop(sqe);
+ sqe->user_data = 2;
+ }
+
+ ret = io_uring_submit(&ring);
+ if (ret != 63) {
+ fprintf(stderr, "submit: %d\n", ret);
+ return 1;
+ }
+
+ for (i = 0; i < 63; i++) {
+ ret = io_uring_wait_cqe(&ring, &cqe);
+ if (ret) {
+ fprintf(stderr, "wait: %d\n", ret);
+ return 1;
+ }
+
+ switch (cqe->user_data) {
+ case 1: /* eventfd */
+ fprintf(stderr, "eventfd unexpected: %d\n", (int)ptr);
+ return 1;
+ case 2:
+ if (cqe->res) {
+ fprintf(stderr, "nop: %d\n", cqe->res);
+ return 1;
+ }
+ break;
+ }
+ io_uring_cqe_seen(&ring, cqe);
+ }
+
+ ret = io_uring_cq_eventfd_toggle(&ring, true);
+ if (ret) {
+ fprintf(stderr, "io_uring_cq_eventfd_toggle: %d\n", ret);
+ return 1;
+ }
+
+ sqe = io_uring_get_sqe(&ring);
+ io_uring_prep_nop(sqe);
+ sqe->user_data = 2;
+
+ ret = io_uring_submit(&ring);
+ if (ret != 1) {
+ fprintf(stderr, "submit: %d\n", ret);
+ return 1;
+ }
+
+ for (i = 0; i < 2; i++) {
+ ret = io_uring_wait_cqe(&ring, &cqe);
+ if (ret) {
+ fprintf(stderr, "wait: %d\n", ret);
+ return 1;
+ }
+
+ switch (cqe->user_data) {
+ case 1: /* eventfd */
+ if (cqe->res != sizeof(ptr)) {
+ fprintf(stderr, "read res: %d\n", cqe->res);
+ return 1;
+ }
+
+ if (ptr != 1) {
+ fprintf(stderr, "eventfd: %d\n", (int)ptr);
+ return 1;
+ }
+ break;
+ case 2:
+ if (cqe->res) {
+ fprintf(stderr, "nop: %d\n", cqe->res);
+ return 1;
+ }
+ break;
+ }
+ io_uring_cqe_seen(&ring, cqe);
+ }
+
+ return 0;
+}
--
2.25.4
Signed-off-by: Stefano Garzarella <[email protected]>
---
man/io_uring_setup.2 | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/man/io_uring_setup.2 b/man/io_uring_setup.2
index d48bb32..c929cb7 100644
--- a/man/io_uring_setup.2
+++ b/man/io_uring_setup.2
@@ -325,7 +325,8 @@ struct io_cqring_offsets {
__u32 ring_entries;
__u32 overflow;
__u32 cqes;
- __u32 resv[4];
+ __u32 flags;
+ __u32 resv[3];
};
.EE
.in
--
2.25.4
io_uring provides the new CQ ring 'flags' field if 'cq_off.flags'
is not zero. In this case we set the 'cq->kflags' pointer, otherwise
it will be NULL.
Signed-off-by: Stefano Garzarella <[email protected]>
---
src/include/liburing.h | 1 +
src/include/liburing/io_uring.h | 4 +++-
src/setup.c | 2 ++
3 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/src/include/liburing.h b/src/include/liburing.h
index 4311325..adc8db9 100644
--- a/src/include/liburing.h
+++ b/src/include/liburing.h
@@ -41,6 +41,7 @@ struct io_uring_cq {
unsigned *ktail;
unsigned *kring_mask;
unsigned *kring_entries;
+ unsigned *kflags;
unsigned *koverflow;
struct io_uring_cqe *cqes;
diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
index a279151..9860a8a 100644
--- a/src/include/liburing/io_uring.h
+++ b/src/include/liburing/io_uring.h
@@ -205,7 +205,9 @@ struct io_cqring_offsets {
__u32 ring_entries;
__u32 overflow;
__u32 cqes;
- __u64 resv[2];
+ __u32 flags;
+ __u32 resv1;
+ __u64 resv2;
};
/*
diff --git a/src/setup.c b/src/setup.c
index f783b6a..860c112 100644
--- a/src/setup.c
+++ b/src/setup.c
@@ -76,6 +76,8 @@ err:
cq->kring_entries = cq->ring_ptr + p->cq_off.ring_entries;
cq->koverflow = cq->ring_ptr + p->cq_off.overflow;
cq->cqes = cq->ring_ptr + p->cq_off.cqes;
+ if (p->cq_off.flags)
+ cq->kflags = cq->ring_ptr + p->cq_off.flags;
return 0;
}
--
2.25.4
Signed-off-by: Stefano Garzarella <[email protected]>
---
man/io_uring_register.2 | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/man/io_uring_register.2 b/man/io_uring_register.2
index e64f688..5022c03 100644
--- a/man/io_uring_register.2
+++ b/man/io_uring_register.2
@@ -168,6 +168,14 @@ must contain a pointer to the eventfd file descriptor, and
.I nr_args
must be 1. Available since 5.2.
+An application can temporarily disable notifications, coming through the
+registered eventfd, by setting the
+.B IORING_CQ_EVENTFD_DISABLED
+bit in the
+.I flags
+field of the CQ ring.
+Available since 5.8.
+
.TP
.B IORING_REGISTER_EVENTFD_ASYNC
This works just like
--
2.25.4
On 5/20/20 11:07 AM, Stefano Garzarella wrote:
> This series is based on top of a new IORING_CQ_EVENTFD_DISABLED
> flag available in the CQ ring flags.
>
> I added io_uring_cq_eventfd_enabled() to get the status of eventfd
> notifications, and io_uring_cq_eventfd_toggle() to disable/enabled
> eventfd notifications.
>
> I updated man pages and I added a eventfd-disable.c test case.
>
> v1 -> v2:
> - renamed io_uring_cq_eventfd_toggle()
> - return EOPNOTSUPP only if we need to change the flag
Applied, thanks.
--
Jens Axboe