Commit fa84693b authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: ensure IORING_REGISTER_IOWQ_MAX_WORKERS works with SQPOLL 

SQPOLL has a different thread doing submissions, we need to check for
that and use the right task context when updating the worker values.
Just hold the sqd->lock across the operation, this ensures that the
thread cannot go away while we poke at ->io_uring.

Link: https://github.com/axboe/liburing/issues/420


Fixes: 2e480058 ("io-wq: provide a way to limit max number of workers")
Reported-by: default avatarJohannes Lundberg <johalun0@gmail.com>
Tested-by: default avatarJohannes Lundberg <johalun0@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3146cba9

fs/io_uring.c

+24 −4
Original line number Diff line number Diff line
@@ -10323,26 +10323,46 @@ static int io_unregister_iowq_aff(struct io_ring_ctx *ctx) 
static int io_register_iowq_max_workers(struct io_ring_ctx *ctx,

					void __user *arg)

{

	struct io_uring_task *tctx = current->io_uring;

	struct io_uring_task *tctx = NULL;

	struct io_sq_data *sqd = NULL;

	__u32 new_count[2];

	int i, ret;



	if (!tctx || !tctx->io_wq)

		return -EINVAL;

	if (copy_from_user(new_count, arg, sizeof(new_count)))

		return -EFAULT;

	for (i = 0; i < ARRAY_SIZE(new_count); i++)

		if (new_count[i] > INT_MAX)

			return -EINVAL;



	if (ctx->flags & IORING_SETUP_SQPOLL) {

		sqd = ctx->sq_data;

		if (sqd) {

			mutex_lock(&sqd->lock);

			tctx = sqd->thread->io_uring;

		}

	} else {

		tctx = current->io_uring;

	}



	ret = -EINVAL;

	if (!tctx || !tctx->io_wq)

		goto err;



	ret = io_wq_max_workers(tctx->io_wq, new_count);

	if (ret)

		return ret;

		goto err;



	if (sqd)

		mutex_unlock(&sqd->lock);



	if (copy_to_user(arg, new_count, sizeof(new_count)))

		return -EFAULT;



	return 0;

err:

	if (sqd)

		mutex_unlock(&sqd->lock);

	return ret;

}



static bool io_register_op_must_quiesce(int op)