RE: [PATCH 1/6] io_uring/cancel: add generic remove_all helper

[lizetao <lizetao1@huawei.com>]

> -----Original Message-----
> From: Jens Axboe <axboe@kernel.dk>
> Sent: Thursday, February 6, 2025 4:26 AM
> To: io-uring@vger.kernel.org
> Cc: Jens Axboe <axboe@kernel.dk>
> Subject: [PATCH 1/6] io_uring/cancel: add generic remove_all helper
> 
> Any opcode that is cancelable ends up defining its own remove all helper, which
> iterates the pending list and cancels matches. Add a generic helper for it, which
> can be used by them.
> 
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
>  io_uring/cancel.c | 20 ++++++++++++++++++++  io_uring/cancel.h |  4 ++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/io_uring/cancel.c b/io_uring/cancel.c index
> 484193567839..0565dc0d7611 100644
> --- a/io_uring/cancel.c
> +++ b/io_uring/cancel.c
> @@ -341,3 +341,23 @@ int io_sync_cancel(struct io_ring_ctx *ctx, void __user
> *arg)
>  		fput(file);
>  	return ret;
>  }
> +
> +bool io_cancel_remove_all(struct io_ring_ctx *ctx, struct io_uring_task *tctx,
> +			  struct hlist_head *list, bool cancel_all,
> +			  bool (*cancel)(struct io_kiocb *)) {
> +	struct hlist_node *tmp;
> +	struct io_kiocb *req;
> +	bool found = false;
> +
> +	lockdep_assert_held(&ctx->uring_lock);
> +
> +	hlist_for_each_entry_safe(req, tmp, list, hash_node) {
> +		if (!io_match_task_safe(req, tctx, cancel_all))
> +			continue;

Should call hlist_del_init(&req->hash_node) here, just like the original code logic.
> +		if (cancel(req))
> +			found = true;
> +	}
> +
> +	return found;
> +}
> diff --git a/io_uring/cancel.h b/io_uring/cancel.h index
> bbfea2cd00ea..80734a0a2b26 100644
> --- a/io_uring/cancel.h
> +++ b/io_uring/cancel.h
> @@ -24,6 +24,10 @@ int io_try_cancel(struct io_uring_task *tctx, struct
> io_cancel_data *cd,  int io_sync_cancel(struct io_ring_ctx *ctx, void __user
> *arg);  bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data
> *cd);
> 
> +bool io_cancel_remove_all(struct io_ring_ctx *ctx, struct io_uring_task *tctx,
> +			  struct hlist_head *list, bool cancel_all,
> +			  bool (*cancel)(struct io_kiocb *));
> +
>  static inline bool io_cancel_match_sequence(struct io_kiocb *req, int sequence)
> {
>  	if (req->cancel_seq_set && sequence == req->work.cancel_seq)
> --
> 2.47.2
> 

---
Li Zetao