From 80fbd584adf480f62e3282d570f67767c74c13d3 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 14 Feb 2024 15:05:57 -0500
Subject: ioq: Factor out io_uring initialization

---
 src/ioq.c | 110 +++++++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 73 insertions(+), 37 deletions(-)

(limited to 'src')

diff --git a/src/ioq.c b/src/ioq.c
index 0126f5c..3c26814 100644
--- a/src/ioq.c
+++ b/src/ioq.c
@@ -712,6 +712,75 @@ static void *ioq_work(void *ptr) {
 	return NULL;
 }
 
+/** Initialize io_uring thread state. */
+static int ioq_ring_init(struct ioq *ioq, struct ioq_thread *thread) {
+#if BFS_USE_LIBURING
+	struct ioq_thread *prev = NULL;
+	if (thread > ioq->threads) {
+		prev = thread - 1;
+	}
+
+	if (prev && prev->ring_err) {
+		thread->ring_err = prev->ring_err;
+		return -1;
+	}
+
+	// Share io-wq workers between rings
+	struct io_uring_params params = {0};
+	if (prev) {
+		params.flags |= IORING_SETUP_ATTACH_WQ;
+		params.wq_fd = prev->ring.ring_fd;
+	}
+
+	// Use a page for each SQE ring
+	size_t entries = 4096 / sizeof(struct io_uring_sqe);
+	thread->ring_err = -io_uring_queue_init_params(entries, &thread->ring, &params);
+	if (thread->ring_err) {
+		return -1;
+	}
+
+	if (!prev) {
+		// Limit the number of io_uring workers
+		unsigned int values[] = {
+			[IO_WQ_BOUND] = ioq->nthreads,
+			[IO_WQ_UNBOUND] = 0,
+		};
+		io_uring_register_iowq_max_workers(&thread->ring, values);
+	}
+#endif
+
+	return 0;
+}
+
+/** Destroy an io_uring. */
+static void ioq_ring_exit(struct ioq_thread *thread) {
+#if BFS_USE_LIBURING
+	if (thread->ring_err == 0) {
+		io_uring_queue_exit(&thread->ring);
+	}
+#endif
+}
+
+/** Create an I/O queue thread. */
+static int ioq_thread_create(struct ioq *ioq, struct ioq_thread *thread) {
+	thread->parent = ioq;
+
+	ioq_ring_init(ioq, thread);
+
+	if (thread_create(&thread->id, NULL, ioq_work, thread) != 0) {
+		ioq_ring_exit(thread);
+		return -1;
+	}
+
+	return 0;
+}
+
+/** Join an I/O queue thread. */
+static void ioq_thread_join(struct ioq_thread *thread) {
+	thread_join(thread->id, NULL);
+	ioq_ring_exit(thread);
+}
+
 struct ioq *ioq_create(size_t depth, size_t nthreads) {
 	struct ioq *ioq = ZALLOC_FLEX(struct ioq, threads, nthreads);
 	if (!ioq) {
@@ -736,41 +805,12 @@ struct ioq *ioq_create(size_t depth, size_t nthreads) {
 		goto fail;
 	}
 
+	ioq->nthreads = nthreads;
 	for (size_t i = 0; i < nthreads; ++i) {
-		struct ioq_thread *thread = &ioq->threads[i];
-		thread->parent = ioq;
-
-#if BFS_USE_LIBURING
-		struct ioq_thread *prev = i ? &ioq->threads[i - 1] : NULL;
-		if (prev && prev->ring_err) {
-			thread->ring_err = prev->ring_err;
-		} else {
-			// Share io-wq workers between rings
-			struct io_uring_params params = {0};
-			if (prev) {
-				params.flags |= IORING_SETUP_ATTACH_WQ;
-				params.wq_fd = prev->ring.ring_fd;
-			}
-
-			// Use a page for each SQE ring
-			size_t entries = 4096 / sizeof(struct io_uring_sqe);
-			thread->ring_err = -io_uring_queue_init_params(entries, &thread->ring, &params);
-
-			if (!prev && thread->ring_err == 0) {
-				// Limit the number of io_uring workers
-				unsigned int values[] = {
-					[IO_WQ_BOUND] = nthreads,
-					[IO_WQ_UNBOUND] = 0,
-				};
-				io_uring_register_iowq_max_workers(&thread->ring, values);
-			}
-		}
-#endif
-
-		if (thread_create(&thread->id, NULL, ioq_work, thread) != 0) {
+		if (ioq_thread_create(ioq, &ioq->threads[i]) != 0) {
+			ioq->nthreads = i;
 			goto fail;
 		}
-		++ioq->nthreads;
 	}
 
 	return ioq;
@@ -908,11 +948,7 @@ void ioq_destroy(struct ioq *ioq) {
 	ioq_cancel(ioq);
 
 	for (size_t i = 0; i < ioq->nthreads; ++i) {
-		struct ioq_thread *thread = &ioq->threads[i];
-		thread_join(thread->id, NULL);
-#if BFS_USE_LIBURING
-		io_uring_queue_exit(&thread->ring);
-#endif
+		ioq_thread_join(&ioq->threads[i]);
 	}
 
 	ioqq_destroy(ioq->ready);
-- 
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