Is there any liburing version macro for backward compatibility

[akankshamahajan15]

In our developement code, in some hosts we use older version of liburing and some places we use newer one.
Currently we can't update to new version everywhere.
io_uring_prep_cancel takes user_data asvoid* in older and __u64 in new.
Is there any macro version that I can use so that my code can be compatible with both liburing version.

[YoSTEALTH]

looks like both new and old user_data (addr) is set to __u64 struct io_uring_sqe { __u64 addr;}.

As a monkey-patch could you not write a wrapper function or cast void * to __u64 (unsigned long) user_data vice versa?

ideally io_uring_prep_cancel64 should have been created.

[akankshamahajan15]

With the new version it gives error that cannot convert from void* to __u64 if I use io_uring_prep_cancel(sqe, (void*)user_data.
If I use io_uring_prep_cancel(sqe, (unsigned long)user_data then i get error with older liburing version.

I have hacked it to use

 io_uring_prep_cancel(sqe, 0, 0),
sqe->addr = (unsigned long)user_data;

But its not a clean solution and wondering if there is any version check that I can use.
For older version use older API call
and for new version use new API call.

[YoSTEALTH]

@axboe Looks like
static inline void io_uring_prep_cancel(struct io_uring_sqe *sqe, void *user_data, int flags)
was implemented in Liburing version <= 2.1 how about keeping that as is, and also implementing
static inline void io_uring_prep_cancel64(struct io_uring_sqe *sqe, __u64 user_data, int flags) for next release?

[axboe]

@YoSTEALTH Yeah that's not a bad idea, I'll take a look. It was an unfortunate change in retrospect, but it's not in a release yet at least.

[axboe]

https://git.kernel.dk/cgit/liburing/commit/?id=5e63866e719c47f13a0c43c90019fae912b328d8