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	Only the current owner of a request is allowed to write into req->flags.
Hence, the cancellation path should never touch it. Add a new field
instead of the flag, move it into the 3rd cache line because it should
always be initialised. poll_refs can move further as polling is an
involved process anyway.
It's a minimal patch, in the future we can and should find a better
place for it and remove now unused REQ_F_CANCEL_SEQ.
Fixes: 521223d7c2 ("io_uring/cancel: don't default to setting req->work.cancel_seq")
Cc: stable@vger.kernel.org
Reported-by: Li Shi <sl1589472800@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6827b129f8f0ad76fa9d1f0a773de938b240ffab.1718323430.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
		
	
			
		
			
				
	
	
		
			38 lines
		
	
	
	
		
			962 B
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			38 lines
		
	
	
	
		
			962 B
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0
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#ifndef IORING_CANCEL_H
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#define IORING_CANCEL_H
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#include <linux/io_uring_types.h>
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struct io_cancel_data {
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	struct io_ring_ctx *ctx;
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	union {
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		u64 data;
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		struct file *file;
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	};
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	u8 opcode;
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	u32 flags;
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	int seq;
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};
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int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
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int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags);
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int io_try_cancel(struct io_uring_task *tctx, struct io_cancel_data *cd,
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		  unsigned int issue_flags);
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void init_hash_table(struct io_hash_table *table, unsigned size);
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int io_sync_cancel(struct io_ring_ctx *ctx, void __user *arg);
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bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd);
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static inline bool io_cancel_match_sequence(struct io_kiocb *req, int sequence)
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{
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	if (req->cancel_seq_set && sequence == req->work.cancel_seq)
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		return true;
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	req->cancel_seq_set = true;
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	req->work.cancel_seq = sequence;
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	return false;
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}
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#endif
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