Commit 1ab1edb0 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: pass poll_find lock back 



Instead of using implicit knowledge of what is locked or not after
io_poll_find() and co returns, pass back a pointer to the locked
bucket if any. If set the user must to unlock the spinlock.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/dae1dc5749aa34367812ecf62f82fd3f053aae44.1655371007.git.asml.silence@gmail.com


Reviewed-by: default avatarHao Xu <howeyxu@tencent.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 38513c46

io_uring/poll.c

+26 −20
Original line number Diff line number Diff line
@@ -565,12 +565,15 @@ __cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk, 
}



static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,

				     struct io_cancel_data *cd)

				     struct io_cancel_data *cd,

				     struct io_hash_bucket **out_bucket)

{

	struct io_kiocb *req;

	u32 index = hash_long(cd->data, ctx->cancel_hash_bits);

	struct io_hash_bucket *hb = &ctx->cancel_hash[index];



	*out_bucket = NULL;



	spin_lock(&hb->lock);

	hlist_for_each_entry(req, &hb->list, hash_node) {

		if (cd->data != req->cqe.user_data)
@@ -582,6 +585,7 @@ static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only, 
				continue;

			req->work.cancel_seq = cd->seq;

		}

		*out_bucket = hb;

		return req;

	}

	spin_unlock(&hb->lock);
@@ -589,11 +593,14 @@ static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only, 
}



static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,

					  struct io_cancel_data *cd)

					  struct io_cancel_data *cd,

					  struct io_hash_bucket **out_bucket)

{

	struct io_kiocb *req;

	int i;



	*out_bucket = NULL;



	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {

		struct io_hash_bucket *hb = &ctx->cancel_hash[i];
@@ -605,6 +612,7 @@ static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx, 
			if (cd->seq == req->work.cancel_seq)

				continue;

			req->work.cancel_seq = cd->seq;

			*out_bucket = hb;

			return req;

		}

		spin_unlock(&hb->lock);
@@ -623,23 +631,19 @@ static bool io_poll_disarm(struct io_kiocb *req) 


int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)

{

	struct io_hash_bucket *bucket;

	struct io_kiocb *req;

	u32 index;

	spinlock_t *lock;



	if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY))

		req = io_poll_file_find(ctx, cd);

		req = io_poll_file_find(ctx, cd, &bucket);

	else

		req = io_poll_find(ctx, false, cd);

	if (!req) {

		return -ENOENT;

	} else {

		index = hash_long(req->cqe.user_data, ctx->cancel_hash_bits);

		lock = &ctx->cancel_hash[index].lock;

	}

		req = io_poll_find(ctx, false, cd, &bucket);



	if (req)

		io_poll_cancel_req(req);

	spin_unlock(lock);

	return 0;

	if (bucket)

		spin_unlock(&bucket->lock);

	return req ? 0 : -ENOENT;

}



static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe,
@@ -732,19 +736,21 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags) 
	struct io_poll_update *poll_update = io_kiocb_to_cmd(req);

	struct io_cancel_data cd = { .data = poll_update->old_user_data, };

	struct io_ring_ctx *ctx = req->ctx;

	u32 index = hash_long(cd.data, ctx->cancel_hash_bits);

	spinlock_t *lock = &ctx->cancel_hash[index].lock;

	struct io_hash_bucket *bucket;

	struct io_kiocb *preq;

	int ret2, ret = 0;

	bool locked;



	preq = io_poll_find(ctx, true, &cd);

	preq = io_poll_find(ctx, true, &cd, &bucket);

	if (preq)

		ret2 = io_poll_disarm(preq);

	if (bucket)

		spin_unlock(&bucket->lock);



	if (!preq) {

		ret = -ENOENT;

		goto out;

	}

	ret2 = io_poll_disarm(preq);

	spin_unlock(lock);

	if (!ret2) {

		ret = -EALREADY;

		goto out;