linux-kernel - [PATCH 07/10] netfs: Fix missing barriers by using clear_and_wake_up

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Message-ID: <20241213135013.2964079-8-dhowells@redhat.com>
Date: Fri, 13 Dec 2024 13:50:07 +0000
From: David Howells <dhowells@...hat.com>
To: Christian Brauner <christian@...uner.io>
Cc: David Howells <dhowells@...hat.com>,
	Max Kellermann <max.kellermann@...os.com>,
	Ilya Dryomov <idryomov@...il.com>,
	Xiubo Li <xiubli@...hat.com>,
	Trond Myklebust <trondmy@...nel.org>,
	Jeff Layton <jlayton@...nel.org>,
	Matthew Wilcox <willy@...radead.org>,
	netfs@...ts.linux.dev,
	linux-afs@...ts.infradead.org,
	linux-cifs@...r.kernel.org,
	linux-nfs@...r.kernel.org,
	ceph-devel@...r.kernel.org,
	v9fs@...ts.linux.dev,
	linux-erofs@...ts.ozlabs.org,
	linux-fsdevel@...r.kernel.org,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Zilin Guan <zilin@....edu.cn>,
	Akira Yokosawa <akiyks@...il.com>
Subject: [PATCH 07/10] netfs: Fix missing barriers by using clear_and_wake_up_bit()

Use clear_and_wake_up_bit() rather than something like:

	clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
	wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS);

as there needs to be a barrier inserted between which is present in
clear_and_wake_up_bit().

Fixes: 288ace2f57c9 ("netfs: New writeback implementation")
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Signed-off-by: David Howells <dhowells@...hat.com>
cc: Zilin Guan <zilin@....edu.cn>
cc: Akira Yokosawa <akiyks@...il.com>
cc: Jeff Layton <jlayton@...nel.org>
cc: netfs@...ts.linux.dev
cc: linux-fsdevel@...r.kernel.org
---
 fs/netfs/read_collect.c  | 3 +--
 fs/netfs/write_collect.c | 9 +++------
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c
index b415e3972336..46ce3b7adf07 100644
--- a/fs/netfs/read_collect.c
+++ b/fs/netfs/read_collect.c
@@ -379,8 +379,7 @@ static void netfs_rreq_assess(struct netfs_io_request *rreq)
 	task_io_account_read(rreq->transferred);
 
 	trace_netfs_rreq(rreq, netfs_rreq_trace_wake_ip);
-	clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
-	wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS);
+	clear_and_wake_up_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
 
 	trace_netfs_rreq(rreq, netfs_rreq_trace_done);
 	netfs_clear_subrequests(rreq, false);
diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c
index 1d438be2e1b4..82290c92ba7a 100644
--- a/fs/netfs/write_collect.c
+++ b/fs/netfs/write_collect.c
@@ -501,8 +501,7 @@ static void netfs_collect_write_results(struct netfs_io_request *wreq)
 		goto need_retry;
 	if ((notes & MADE_PROGRESS) && test_bit(NETFS_RREQ_PAUSE, &wreq->flags)) {
 		trace_netfs_rreq(wreq, netfs_rreq_trace_unpause);
-		clear_bit_unlock(NETFS_RREQ_PAUSE, &wreq->flags);
-		wake_up_bit(&wreq->flags, NETFS_RREQ_PAUSE);
+		clear_and_wake_up_bit(NETFS_RREQ_PAUSE, &wreq->flags);
 	}
 
 	if (notes & NEED_REASSESS) {
@@ -605,8 +604,7 @@ void netfs_write_collection_worker(struct work_struct *work)
 
 	_debug("finished");
 	trace_netfs_rreq(wreq, netfs_rreq_trace_wake_ip);
-	clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &wreq->flags);
-	wake_up_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS);
+	clear_and_wake_up_bit(NETFS_RREQ_IN_PROGRESS, &wreq->flags);
 
 	if (wreq->iocb) {
 		size_t written = min(wreq->transferred, wreq->len);
@@ -714,8 +712,7 @@ void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error,
 
 	trace_netfs_sreq(subreq, netfs_sreq_trace_terminated);
 
-	clear_bit_unlock(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
-	wake_up_bit(&subreq->flags, NETFS_SREQ_IN_PROGRESS);
+	clear_and_wake_up_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
 
 	/* If we are at the head of the queue, wake up the collector,
 	 * transferring a ref to it if we were the ones to do so.