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authorJens Axboe <axboe@kernel.dk>2022-05-25 17:56:52 +0300
committerJens Axboe <axboe@kernel.dk>2022-07-25 03:39:12 +0300
commite418bbc97bffda868934acfdf8a1173ab044be69 (patch)
tree02a9de325cc875f6ec91066c2795876666715688 /io_uring/refs.h
parent36404b09aa609e00f8f0108356830c22b99b3cbf (diff)
downloadlinux-e418bbc97bffda868934acfdf8a1173ab044be69.tar.xz
io_uring: move our reference counting into a header
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/refs.h')
-rw-r--r--io_uring/refs.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/io_uring/refs.h b/io_uring/refs.h
new file mode 100644
index 000000000000..334c5ead4c43
--- /dev/null
+++ b/io_uring/refs.h
@@ -0,0 +1,48 @@
+#ifndef IOU_REQ_REF_H
+#define IOU_REQ_REF_H
+
+#include <linux/atomic.h>
+#include "io_uring_types.h"
+
+/*
+ * Shamelessly stolen from the mm implementation of page reference checking,
+ * see commit f958d7b528b1 for details.
+ */
+#define req_ref_zero_or_close_to_overflow(req) \
+ ((unsigned int) atomic_read(&(req->refs)) + 127u <= 127u)
+
+static inline bool req_ref_inc_not_zero(struct io_kiocb *req)
+{
+ WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT));
+ return atomic_inc_not_zero(&req->refs);
+}
+
+static inline bool req_ref_put_and_test(struct io_kiocb *req)
+{
+ if (likely(!(req->flags & REQ_F_REFCOUNT)))
+ return true;
+
+ WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
+ return atomic_dec_and_test(&req->refs);
+}
+
+static inline void req_ref_get(struct io_kiocb *req)
+{
+ WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT));
+ WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
+ atomic_inc(&req->refs);
+}
+
+static inline void __io_req_set_refcount(struct io_kiocb *req, int nr)
+{
+ if (!(req->flags & REQ_F_REFCOUNT)) {
+ req->flags |= REQ_F_REFCOUNT;
+ atomic_set(&req->refs, nr);
+ }
+}
+
+static inline void io_req_set_refcount(struct io_kiocb *req)
+{
+ __io_req_set_refcount(req, 1);
+}
+#endif