From e13fb1fe1483f6cd6452f25b866ffadf5ee0eff6 Mon Sep 17 00:00:00 2001
From: Hao Xu <haoxu@linux.alibaba.com>
Date: Sun, 6 Feb 2022 17:52:40 +0800
Subject: [PATCH] io-wq: reduce acct->lock crossing functions lock/unlock
Git-commit: e13fb1fe1483f6cd6452f25b866ffadf5ee0eff6
Patch-mainline: v5.18-rc1
References: bsc#1205205

reduce acct->lock lock and unlock in different functions to make the
code clearer.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220206095241.121485-3-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
 fs/io-wq.c |   32 ++++++++++++--------------------
 1 file changed, 12 insertions(+), 20 deletions(-)

--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -238,10 +238,15 @@ static void io_worker_exit(struct io_wor
 
 static inline bool io_acct_run_queue(struct io_wqe_acct *acct)
 {
+	bool ret = false;
+
+	raw_spin_lock(&acct->lock);
 	if (!wq_list_empty(&acct->work_list) &&
 	    !test_bit(IO_ACCT_STALLED_BIT, &acct->flags))
-		return true;
-	return false;
+		ret = true;
+	raw_spin_unlock(&acct->lock);
+
+	return ret;
 }
 
 /*
@@ -394,13 +399,9 @@ static void io_wqe_dec_running(struct io
 
 	if (!atomic_dec_and_test(&acct->nr_running))
 		return;
-	raw_spin_lock(&wqe->lock);
-	if (!io_acct_run_queue(acct)) {
-		raw_spin_unlock(&wqe->lock);
+	if (!io_acct_run_queue(acct))
 		return;
-	}
 
-	raw_spin_unlock(&wqe->lock);
 	atomic_inc(&acct->nr_running);
 	atomic_inc(&wqe->wq->worker_refs);
 	io_queue_worker_create(worker, acct, create_worker_cb);
@@ -543,7 +544,6 @@ static void io_assign_current_work(struc
 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work);
 
 static void io_worker_handle_work(struct io_worker *worker)
-	__releases(acct->lock)
 {
 	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
 	struct io_wqe *wqe = worker->wqe;
@@ -560,6 +560,7 @@ static void io_worker_handle_work(struct
 		 * can't make progress, any work completion or insertion will
 		 * clear the stalled flag.
 		 */
+		raw_spin_lock(&acct->lock);
 		work = io_get_next_work(acct, worker);
 		raw_spin_unlock(&acct->lock);
 		if (work) {
@@ -613,8 +614,6 @@ static void io_worker_handle_work(struct
 					wake_up(&wq->hash->wait);
 			}
 		} while (work);
-
-		raw_spin_lock(&acct->lock);
 	} while (1);
 }
 
@@ -636,14 +635,9 @@ static int io_wqe_worker(void *data)
 		long ret;
 
 		set_current_state(TASK_INTERRUPTIBLE);
-loop:
-		raw_spin_lock(&acct->lock);
-		if (io_acct_run_queue(acct)) {
+		while (io_acct_run_queue(acct))
 			io_worker_handle_work(worker);
-			goto loop;
-		} else {
-			raw_spin_unlock(&acct->lock);
-		}
+
 		raw_spin_lock(&wqe->lock);
 		/* timed out, exit unless we're the last worker */
 		if (last_timeout && acct->nr_workers > 1) {
@@ -668,10 +662,8 @@ loop:
 		last_timeout = !ret;
 	}
 
-	if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
-		raw_spin_lock(&acct->lock);
+	if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
 		io_worker_handle_work(worker);
-	}
 
 	io_worker_exit(worker);
 	return 0;