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[188.142.152.55]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c317c2fae53sm204251866b.49.2026.10.08.04.20.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Oct 2026 04:20:11 -0700 (PDT) From: Miklos Szeredi To: fuse-devel@lists.linux.dev Cc: John Groves , Amir Goldstein , "Darrick J . Wong" , Vishal Verma , Dave Jiang , Alison Schofield , nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org Subject: [PATCH v4 2/9] dax: use READ_ONCE() in dax_holder() Date: Thu, 8 Oct 2026 13:19:53 +0200 Message-ID: <20261008112004.1899560-3-mszeredi@redhat.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20261008112004.1899560-1-mszeredi@redhat.com> References: <20261008112004.1899560-1-mszeredi@redhat.com> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: AtamFbLg1gzJEB6uavZ6NI10kIM_3yizkooLJ3C8W_Y_1791458413 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true A future fuse patch will utilize dax_holder() in RCU context to make sure that the holder can't be freed by a racing fs_put_dax. This patch just makes sure that dax_holder() works properly in such a context by adding READ_ONCE() (equivalent to rcu_dereference minus sanity checks). Signed-off-by: Miklos Szeredi --- drivers/dax/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 25836f389bde..76e8d3654629 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -642,7 +642,7 @@ EXPORT_SYMBOL_GPL(put_dax); */ void *dax_holder(struct dax_device *dax_dev) { - return dax_dev->holder_data; + return READ_ONCE(dax_dev->holder_data); } EXPORT_SYMBOL_GPL(dax_holder); -- 2.54.0