[PATCH v2] io-wq: expose IO_WQ_ACCT_* enumeration items to UAPI

These are used to index elements in the argument
of IORING_REGISTER_IOWQ_MAX_WORKERS io_uring_register command,
so they are to be exposed in UAPI.

Complements: 2e480058ddc21ec5 ("io-wq: provide a way to limit max number of workers")
Signed-off-by: Eugene Syromiatnikov <redacted>
---
v2:
 - IO_WQ_ACCT_NR is no longer exposed directly in UAPI, per Jens Axboe's
   suggestion.

v1: https://lore.kernel.org/lkml/20210912122411.GA27679@asgard.redhat.com/
---
 fs/io-wq.c                    | 5 ++---
 include/uapi/linux/io_uring.h | 8 ++++++++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 6c55362..eb5162d 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c

@@ -14,6 +14,7 @@
 #include <linux/rculist_nulls.h>
 #include <linux/cpu.h>
 #include <linux/tracehook.h>
+#include <uapi/linux/io_uring.h>
 
 #include "io-wq.h"
 

@@ -78,9 +79,7 @@ struct io_wqe_acct {
 };
 
 enum {
-	IO_WQ_ACCT_BOUND,
-	IO_WQ_ACCT_UNBOUND,
-	IO_WQ_ACCT_NR,
+	IO_WQ_ACCT_NR = __IO_WQ_ACCT_MAX
 };
 
 /*

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 59ef351..dae1841 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h

@@ -324,6 +324,14 @@ enum {
 	IORING_REGISTER_LAST
 };
 
+/* io-wq worker limit categories */
+enum {
+	IO_WQ_ACCT_BOUND,
+	IO_WQ_ACCT_UNBOUND,
+
+	__IO_WQ_ACCT_MAX /* Non-UAPI */
+};
+
 /* deprecated, see struct io_uring_rsrc_update */
 struct io_uring_files_update {
 	__u32 offset;

-- 
2.1.4

On 9/13/21 4:41 AM, Eugene Syromiatnikov wrote:

This is really the same thing as before, just the names have changed.
What I suggested was keeping the enum in io_uring, then just adding

enum {
	IO_WQ_BOUND,
	IO_WQ_UNBOUND,
};

to uapi header. The ACCT stuff is io-wq specific too, that kind of naming
shouldn't be propagated to userspace.

A BUILD_BUG_ON() could be added for them being different, but honestly
I don't think that's worth it.

-- 
Jens Axboe

On Mon, Sep 13, 2021 at 07:28:11AM -0600, Jens Axboe wrote:

This is really the same thing as before, just the names have changed.
What I suggested was keeping the enum in io_uring, then just adding

enum {
	IO_WQ_BOUND,
	IO_WQ_UNBOUND,
};

to uapi header. The ACCT stuff is io-wq specific too, that kind of naming
shouldn't be propagated to userspace.

My apologies, I've overlooked the fact that the proposed names
are different.  Updated and resent[1].

[1] https://lore.kernel.org/lkml/20210913154415.GA12890@asgard.redhat.com/

A BUILD_BUG_ON() could be added for them being different, but honestly
I don't think that's worth it.