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

[Jens Axboe <axboe@kernel.dk>]

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;
+		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