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From:   Kent Overstreet <kent.overstreet@linux.dev>
To:     linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-bcachefs@vger.kernel.org
Cc:     Kent Overstreet <kent.overstreet@gmail.com>,
        Coly Li <colyli@suse.de>,
        Kent Overstreet <kent.overstreet@linux.dev>
Subject: [PATCH 17/32] closures: closure_wait_event()
Date:   Tue,  9 May 2023 12:56:42 -0400
Message-Id: <20230509165657.1735798-18-kent.overstreet@linux.dev>
In-Reply-To: <20230509165657.1735798-1-kent.overstreet@linux.dev>
References: <20230509165657.1735798-1-kent.overstreet@linux.dev>
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From: Kent Overstreet <kent.overstreet@gmail.com>

Like wait_event() - except, because it uses closures and closure
waitlists it doesn't have the restriction on modifying task state inside
the condition check, like wait_event() does.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Acked-by: Coly Li <colyli@suse.de>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 include/linux/closure.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/linux/closure.h b/include/linux/closure.h
index 0ec9e7bc8d..36b4a83f9b 100644
--- a/include/linux/closure.h
+++ b/include/linux/closure.h
@@ -374,4 +374,26 @@ static inline void closure_call(struct closure *cl, closure_fn fn,
 	continue_at_nobarrier(cl, fn, wq);
 }
 
+#define __closure_wait_event(waitlist, _cond)				\
+do {									\
+	struct closure cl;						\
+									\
+	closure_init_stack(&cl);					\
+									\
+	while (1) {							\
+		closure_wait(waitlist, &cl);				\
+		if (_cond)						\
+			break;						\
+		closure_sync(&cl);					\
+	}								\
+	closure_wake_up(waitlist);					\
+	closure_sync(&cl);						\
+} while (0)
+
+#define closure_wait_event(waitlist, _cond)				\
+do {									\
+	if (!(_cond))							\
+		__closure_wait_event(waitlist, _cond);			\
+} while (0)
+
 #endif /* _LINUX_CLOSURE_H */
-- 
2.40.1