* [PATCH] io_uring: add IORING_OP_NOP_FAIL
@ 2024-05-09 2:34 Ming Lei
2024-05-09 2:55 ` Jens Axboe
0 siblings, 1 reply; 5+ messages in thread
From: Ming Lei @ 2024-05-09 2:34 UTC (permalink / raw)
To: Jens Axboe, io-uring; +Cc: Ming Lei
Add IORING_OP_NOP_FAIL so that it is easy to inject failure from
userspace.
Like IORING_OP_NOP, the main use case is test, and it is very helpful
for covering failure handling code in io_uring core change.
Signed-off-by: Ming Lei <[email protected]>
---
include/uapi/linux/io_uring.h | 2 ++
io_uring/nop.c | 27 +++++++++++++++++++++++++++
io_uring/nop.h | 3 +++
io_uring/opdef.c | 9 +++++++++
4 files changed, 41 insertions(+)
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 922f29b07ccc..18e58477e0f0 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -72,6 +72,7 @@ struct io_uring_sqe {
__u32 waitid_flags;
__u32 futex_flags;
__u32 install_fd_flags;
+ __s32 nop_fail_res;
};
__u64 user_data; /* data to be passed back at completion time */
/* pack this to avoid bogus arm OABI complaints */
@@ -259,6 +260,7 @@ enum io_uring_op {
IORING_OP_FUTEX_WAITV,
IORING_OP_FIXED_FD_INSTALL,
IORING_OP_FTRUNCATE,
+ IORING_OP_NOP_FAIL,
/* this goes last, obviously */
IORING_OP_LAST,
diff --git a/io_uring/nop.c b/io_uring/nop.c
index d956599a3c1b..c30547e53b5c 100644
--- a/io_uring/nop.c
+++ b/io_uring/nop.c
@@ -10,6 +10,12 @@
#include "io_uring.h"
#include "nop.h"
+struct io_nop_fail {
+ /* NOTE: kiocb has the file as the first member, so don't do it here */
+ struct file *file;
+ int res;
+};
+
int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return 0;
@@ -23,3 +29,24 @@ int io_nop(struct io_kiocb *req, unsigned int issue_flags)
io_req_set_res(req, 0, 0);
return IOU_OK;
}
+
+int io_nop_fail_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+ struct io_nop_fail *nf = io_kiocb_to_cmd(req, struct io_nop_fail);
+
+ nf->res = READ_ONCE(sqe->nop_fail_res);
+ return 0;
+}
+
+/*
+ * IORING_OP_NOP just posts a completion event, nothing else.
+ */
+int io_nop_fail(struct io_kiocb *req, unsigned int issue_flags)
+{
+ struct io_nop_fail *nf = io_kiocb_to_cmd(req, struct io_nop_fail);
+
+ if (nf->res < 0)
+ req_set_fail(req);
+ io_req_set_res(req, nf->res, 0);
+ return IOU_OK;
+}
diff --git a/io_uring/nop.h b/io_uring/nop.h
index 97f1535c9dec..ef40d3b15899 100644
--- a/io_uring/nop.h
+++ b/io_uring/nop.h
@@ -2,3 +2,6 @@
int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_nop(struct io_kiocb *req, unsigned int issue_flags);
+
+int io_nop_fail_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
+int io_nop_fail(struct io_kiocb *req, unsigned int issue_flags);
diff --git a/io_uring/opdef.c b/io_uring/opdef.c
index 92b657a063a0..eadc5a12ee06 100644
--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -56,6 +56,12 @@ const struct io_issue_def io_issue_defs[] = {
.prep = io_nop_prep,
.issue = io_nop,
},
+ [IORING_OP_NOP_FAIL] = {
+ .audit_skip = 1,
+ .iopoll = 1,
+ .prep = io_nop_fail_prep,
+ .issue = io_nop_fail,
+ },
[IORING_OP_READV] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
@@ -506,6 +512,9 @@ const struct io_cold_def io_cold_defs[] = {
[IORING_OP_NOP] = {
.name = "NOP",
},
+ [IORING_OP_NOP_FAIL] = {
+ .name = "NOP_FAIL",
+ },
[IORING_OP_READV] = {
.name = "READV",
.cleanup = io_readv_writev_cleanup,
--
2.44.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] io_uring: add IORING_OP_NOP_FAIL
2024-05-09 2:34 [PATCH] io_uring: add IORING_OP_NOP_FAIL Ming Lei
@ 2024-05-09 2:55 ` Jens Axboe
2024-05-09 3:05 ` Ming Lei
0 siblings, 1 reply; 5+ messages in thread
From: Jens Axboe @ 2024-05-09 2:55 UTC (permalink / raw)
To: Ming Lei, io-uring
On 5/8/24 8:34 PM, Ming Lei wrote:
> Add IORING_OP_NOP_FAIL so that it is easy to inject failure from
> userspace.
>
> Like IORING_OP_NOP, the main use case is test, and it is very helpful
> for covering failure handling code in io_uring core change.
Rather than use a new opcode for this, why don't we just add it to
the existing NOP? I know we don't check for flags in currently, so
you would not know if it worked, but we could add that and just
backport that one-liner as well.
And if we had such a flag, the fail res could be passed in as well.
--
Jens Axboe
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] io_uring: add IORING_OP_NOP_FAIL
2024-05-09 2:55 ` Jens Axboe
@ 2024-05-09 3:05 ` Ming Lei
2024-05-09 4:03 ` Ming Lei
2024-05-09 14:02 ` Jens Axboe
0 siblings, 2 replies; 5+ messages in thread
From: Ming Lei @ 2024-05-09 3:05 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring
On Wed, May 08, 2024 at 08:55:09PM -0600, Jens Axboe wrote:
> On 5/8/24 8:34 PM, Ming Lei wrote:
> > Add IORING_OP_NOP_FAIL so that it is easy to inject failure from
> > userspace.
> >
> > Like IORING_OP_NOP, the main use case is test, and it is very helpful
> > for covering failure handling code in io_uring core change.
>
> Rather than use a new opcode for this, why don't we just add it to
> the existing NOP? I know we don't check for flags in currently, so
> you would not know if it worked, but we could add that and just
> backport that one-liner as well.
Yeah, it is just for avoiding to break existed tests which may not build
over liburing.
I will switch to this way, looks one-line backporting can solve it.
> And if we had such a flag, the fail res could be passed in as well.
We can just pass the 'injected_fail_res' via sqe->len, meantime keep
'nop_flags' for error injection and future extension.
thanks,
Ming
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] io_uring: add IORING_OP_NOP_FAIL
2024-05-09 3:05 ` Ming Lei
@ 2024-05-09 4:03 ` Ming Lei
2024-05-09 14:02 ` Jens Axboe
1 sibling, 0 replies; 5+ messages in thread
From: Ming Lei @ 2024-05-09 4:03 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Ming Lei
On Thu, May 9, 2024 at 11:05 AM Ming Lei <[email protected]> wrote:
>
> On Wed, May 08, 2024 at 08:55:09PM -0600, Jens Axboe wrote:
> > On 5/8/24 8:34 PM, Ming Lei wrote:
> > > Add IORING_OP_NOP_FAIL so that it is easy to inject failure from
> > > userspace.
> > >
> > > Like IORING_OP_NOP, the main use case is test, and it is very helpful
> > > for covering failure handling code in io_uring core change.
> >
> > Rather than use a new opcode for this, why don't we just add it to
> > the existing NOP? I know we don't check for flags in currently, so
> > you would not know if it worked, but we could add that and just
> > backport that one-liner as well.
>
> Yeah, it is just for avoiding to break existed tests which may not build
> over liburing.
>
> I will switch to this way, looks one-line backporting can solve it.
I guess backporting can't work, because application code expects
NOP to complete successfully with and w/o non-zero sqe->rw_flags.
However, the backport has to fail NOP in case of non-zero sqe->rw_flags.
Thanks.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] io_uring: add IORING_OP_NOP_FAIL
2024-05-09 3:05 ` Ming Lei
2024-05-09 4:03 ` Ming Lei
@ 2024-05-09 14:02 ` Jens Axboe
1 sibling, 0 replies; 5+ messages in thread
From: Jens Axboe @ 2024-05-09 14:02 UTC (permalink / raw)
To: Ming Lei; +Cc: io-uring
On 5/8/24 9:05 PM, Ming Lei wrote:
> On Wed, May 08, 2024 at 08:55:09PM -0600, Jens Axboe wrote:
>> On 5/8/24 8:34 PM, Ming Lei wrote:
>>> Add IORING_OP_NOP_FAIL so that it is easy to inject failure from
>>> userspace.
>>>
>>> Like IORING_OP_NOP, the main use case is test, and it is very helpful
>>> for covering failure handling code in io_uring core change.
>>
>> Rather than use a new opcode for this, why don't we just add it to
>> the existing NOP? I know we don't check for flags in currently, so
>> you would not know if it worked, but we could add that and just
>> backport that one-liner as well.
>
> Yeah, it is just for avoiding to break existed tests which may not build
> over liburing.
Don't think that's a huge risk, if someone is using the raw interface
and just not clearing, they would run into issues with mixed command
usage anyway. And a pure nop test would be fine anyway, as everything
starts out cleared.
> I will switch to this way, looks one-line backporting can solve it.
Exactly, thanks!
>> And if we had such a flag, the fail res could be passed in as well.
>
> We can just pass the 'injected_fail_res' via sqe->len, meantime keep
> 'nop_flags' for error injection and future extension.
Precisely.
--
Jens Axboe
^ permalink raw reply [flat|nested] 5+ messages in thread
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2024-05-09 2:34 [PATCH] io_uring: add IORING_OP_NOP_FAIL Ming Lei
2024-05-09 2:55 ` Jens Axboe
2024-05-09 3:05 ` Ming Lei
2024-05-09 4:03 ` Ming Lei
2024-05-09 14:02 ` Jens Axboe
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