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([120.245.114.74]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a0b0a708a6sm59372525ad.97.2025.12.15.07.23.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Dec 2025 07:23:27 -0800 (PST) From: Yongpeng Yang To: Damien Le Moal , Jens Axboe , Christoph Hellwig , Ming Lei Cc: linux-block@vger.kernel.org, Yongpeng Yang , Yongpeng Yang Subject: [PATCH v4 2/2] zloop: use READ_ONCE() to read lo->lo_state in queue_rq path Date: Mon, 15 Dec 2025 23:21:06 +0800 Message-ID: <20251215152104.6679-4-yangyongpeng.storage@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251215152104.6679-2-yangyongpeng.storage@gmail.com> References: <20251215152104.6679-2-yangyongpeng.storage@gmail.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Yongpeng Yang In the queue_rq path, zlo->state is accessed without locking, and direct access may read stale data. This patch uses READ_ONCE() to read zlo->state and data_race() to silence code checkers, and changes all assignments to use WRITE_ONCE(). Reviewed-by: Damien Le Moal Reviewed-by: Christoph Hellwig Signed-off-by: Yongpeng Yang --- v3: - Use WRITE_ONCE() instead of assignments to update state. v2: - Use READ_ONCE() instead of converting state to atomic_t type. --- drivers/block/zloop.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/block/zloop.c b/drivers/block/zloop.c index 77bd6081b244..8e334f5025fc 100644 --- a/drivers/block/zloop.c +++ b/drivers/block/zloop.c @@ -697,7 +697,7 @@ static blk_status_t zloop_queue_rq(struct blk_mq_hw_ctx *hctx, struct zloop_cmd *cmd = blk_mq_rq_to_pdu(rq); struct zloop_device *zlo = rq->q->queuedata; - if (zlo->state == Zlo_deleting) + if (data_race(READ_ONCE(zlo->state)) == Zlo_deleting) return BLK_STS_IOERR; /* @@ -1002,7 +1002,7 @@ static int zloop_ctl_add(struct zloop_options *opts) ret = -ENOMEM; goto out; } - zlo->state = Zlo_creating; + WRITE_ONCE(zlo->state, Zlo_creating); ret = mutex_lock_killable(&zloop_ctl_mutex); if (ret) @@ -1113,7 +1113,7 @@ static int zloop_ctl_add(struct zloop_options *opts) } mutex_lock(&zloop_ctl_mutex); - zlo->state = Zlo_live; + WRITE_ONCE(zlo->state, Zlo_live); mutex_unlock(&zloop_ctl_mutex); pr_info("zloop: device %d, %u zones of %llu MiB, %u B block size\n", @@ -1177,7 +1177,7 @@ static int zloop_ctl_remove(struct zloop_options *opts) ret = -EINVAL; } else { idr_remove(&zloop_index_idr, zlo->id); - zlo->state = Zlo_deleting; + WRITE_ONCE(zlo->state, Zlo_deleting); } mutex_unlock(&zloop_ctl_mutex); -- 2.43.0