1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef IOU_REQ_REF_H 3 #define IOU_REQ_REF_H 4 5 #include <linux/atomic.h> 6 #include <linux/io_uring_types.h> 7 8 /* 9 * Shamelessly stolen from the mm implementation of page reference checking, 10 * see commit f958d7b528b1 for details. 11 */ 12 #define req_ref_zero_or_close_to_overflow(req) \ 13 ((unsigned int) atomic_read(&(req->refs)) + 127u <= 127u) 14 15 static inline bool req_ref_inc_not_zero(struct io_kiocb *req) 16 { 17 WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT)); 18 return atomic_inc_not_zero(&req->refs); 19 } 20 21 static inline bool req_ref_put_and_test_atomic(struct io_kiocb *req) 22 { 23 WARN_ON_ONCE(!(data_race(req->flags) & REQ_F_REFCOUNT)); 24 WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req)); 25 return atomic_dec_and_test(&req->refs); 26 } 27 28 static inline bool req_ref_put_and_test(struct io_kiocb *req) 29 { 30 if (likely(!(req->flags & REQ_F_REFCOUNT))) 31 return true; 32 33 WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req)); 34 return atomic_dec_and_test(&req->refs); 35 } 36 37 static inline void req_ref_get(struct io_kiocb *req) 38 { 39 WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT)); 40 WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req)); 41 atomic_inc(&req->refs); 42 } 43 44 static inline void req_ref_put(struct io_kiocb *req) 45 { 46 WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT)); 47 WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req)); 48 atomic_dec(&req->refs); 49 } 50 51 static inline void __io_req_set_refcount(struct io_kiocb *req, int nr) 52 { 53 if (!(req->flags & REQ_F_REFCOUNT)) { 54 req->flags |= REQ_F_REFCOUNT; 55 atomic_set(&req->refs, nr); 56 } 57 } 58 59 static inline void io_req_set_refcount(struct io_kiocb *req) 60 { 61 __io_req_set_refcount(req, 1); 62 } 63 #endif 64