Messages in this thread | | | Date | Mon, 26 Sep 2022 21:29:32 +0100 | Subject | Re: [PATCH v2 1/3] io_uring: register single issuer task at creation | From | Pavel Begunkov <> |
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On 9/26/22 20:40, Jens Axboe wrote: > On 9/26/22 1:12 PM, Pavel Begunkov wrote: >> On 9/26/22 18:09, Dylan Yudaken wrote: >>> Instead of picking the task from the first submitter task, rather use the >>> creator task or in the case of disabled (IORING_SETUP_R_DISABLED) the >>> enabling task. >>> >>> This approach allows a lot of simplification of the logic here. This >>> removes init logic from the submission path, which can always be a bit >>> confusing, but also removes the need for locking to write (or read) the >>> submitter_task. >>> >>> Users that want to move a ring before submitting can create the ring >>> disabled and then enable it on the submitting task. >> >> I think Dylan briefly mentioned before that it might be a good >> idea to task limit registration as well. I can't think of a use >> case at the moment but I agree we may find some in the future. >> >> >> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c >> index 242d896c00f3..60a471e43fd9 100644 >> --- a/io_uring/io_uring.c >> +++ b/io_uring/io_uring.c >> @@ -3706,6 +3706,9 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, >> if (WARN_ON_ONCE(percpu_ref_is_dying(&ctx->refs))) >> return -ENXIO; >> >> + if (ctx->submitter_task && ctx->submitter_task != current) >> + return -EEXIST; >> + >> if (ctx->restricted) { >> if (opcode >= IORING_REGISTER_LAST) >> return -EINVAL; > > Yes, I don't see any reason why not to enforce this for registration > too. Don't think there's currently a need to do so, but it'd be easy > to miss once we do add that. Let's queue that up for 6.1?
6.1 + stable sounds ok, I don't have an opinion on how to how to merge it.
-- Pavel Begunkov
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