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From: Hou Tao <houtao@huaweicloud.com>
To: linux-cachefs@redhat.com
Cc: Jeff Layton <jlayton@kernel.org>,
	linux-kernel@vger.kernel.org, David Howells <dhowells@redhat.com>,
	houtao1@huawei.com, linux-fsdevel@vger.kernel.org,
	linux-erofs@lists.ozlabs.org
Subject: [PATCH v3 2/2] fscache: Use clear_and_wake_up_bit() in fscache_create_volume_work()
Date: Fri, 13 Jan 2023 19:52:11 +0800	[thread overview]
Message-ID: <20230113115211.2895845-3-houtao@huaweicloud.com> (raw)
In-Reply-To: <20230113115211.2895845-1-houtao@huaweicloud.com>

From: Hou Tao <houtao1@huawei.com>

fscache_create_volume_work() uses wake_up_bit() to wake up the processes
which are waiting for the completion of volume creation. According to
comments in wake_up_bit() and waitqueue_active(), an extra smp_mb() is
needed to guarantee the memory order between FSCACHE_VOLUME_CREATING
flag and waitqueue_active() before invoking wake_up_bit().

Fixing it by using clear_and_wake_up_bit() to add the missing memory
barrier.

Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 fs/fscache/volume.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/fscache/volume.c b/fs/fscache/volume.c
index 903af9d85f8b..cdf991bdd9de 100644
--- a/fs/fscache/volume.c
+++ b/fs/fscache/volume.c
@@ -280,8 +280,7 @@ static void fscache_create_volume_work(struct work_struct *work)
 	fscache_end_cache_access(volume->cache,
 				 fscache_access_acquire_volume_end);
 
-	clear_bit_unlock(FSCACHE_VOLUME_CREATING, &volume->flags);
-	wake_up_bit(&volume->flags, FSCACHE_VOLUME_CREATING);
+	clear_and_wake_up_bit(FSCACHE_VOLUME_CREATING, &volume->flags);
 	fscache_put_volume(volume, fscache_volume_put_create_work);
 }
 
-- 
2.29.2


WARNING: multiple messages have this Message-ID (diff)
From: Hou Tao <houtao@huaweicloud.com>
To: linux-cachefs@redhat.com
Cc: David Howells <dhowells@redhat.com>,
	Jeff Layton <jlayton@kernel.org>,
	linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Jingbo Xu <jefflexu@linux.alibaba.com>,
	houtao1@huawei.com
Subject: [PATCH v3 2/2] fscache: Use clear_and_wake_up_bit() in fscache_create_volume_work()
Date: Fri, 13 Jan 2023 19:52:11 +0800	[thread overview]
Message-ID: <20230113115211.2895845-3-houtao@huaweicloud.com> (raw)
In-Reply-To: <20230113115211.2895845-1-houtao@huaweicloud.com>

From: Hou Tao <houtao1@huawei.com>

fscache_create_volume_work() uses wake_up_bit() to wake up the processes
which are waiting for the completion of volume creation. According to
comments in wake_up_bit() and waitqueue_active(), an extra smp_mb() is
needed to guarantee the memory order between FSCACHE_VOLUME_CREATING
flag and waitqueue_active() before invoking wake_up_bit().

Fixing it by using clear_and_wake_up_bit() to add the missing memory
barrier.

Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 fs/fscache/volume.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/fscache/volume.c b/fs/fscache/volume.c
index 903af9d85f8b..cdf991bdd9de 100644
--- a/fs/fscache/volume.c
+++ b/fs/fscache/volume.c
@@ -280,8 +280,7 @@ static void fscache_create_volume_work(struct work_struct *work)
 	fscache_end_cache_access(volume->cache,
 				 fscache_access_acquire_volume_end);
 
-	clear_bit_unlock(FSCACHE_VOLUME_CREATING, &volume->flags);
-	wake_up_bit(&volume->flags, FSCACHE_VOLUME_CREATING);
+	clear_and_wake_up_bit(FSCACHE_VOLUME_CREATING, &volume->flags);
 	fscache_put_volume(volume, fscache_volume_put_create_work);
 }
 
-- 
2.29.2


  parent reply	other threads:[~2023-01-13 11:24 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-13 11:52 [PATCH v3 0/2] Fixes for fscache volume operations Hou Tao
2023-01-13 11:52 ` Hou Tao
2023-01-13 11:52 ` [PATCH v3 1/2] fscache: Use wait_on_bit() to wait for the freeing of relinquished volume Hou Tao
2023-01-13 11:52   ` Hou Tao
2023-01-13 15:27   ` Jeff Layton
2023-01-13 15:27     ` Jeff Layton
2023-01-13 11:52 ` Hou Tao [this message]
2023-01-13 11:52   ` [PATCH v3 2/2] fscache: Use clear_and_wake_up_bit() in fscache_create_volume_work() Hou Tao
2023-01-13 15:28   ` Jeff Layton
2023-01-13 15:28     ` Jeff Layton
2023-01-30 10:56 ` [PATCH v3 0/2] Fixes for fscache volume operations Hou Tao
2023-01-30 10:56   ` Hou Tao

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