From: Yufen Yu <yuyufen@huawei.com>
To: <axboe@kernel.dk>, <linux-block@vger.kernel.org>,
<linux-fsdevel@vger.kernel.org>
Cc: <tj@kernel.org>, <jack@suse.cz>, <bvanassche@acm.org>, <tytso@mit.edu>
Subject: [PATCH v2 4/7] bdi: create a new function bdi_get_dev_name()
Date: Wed, 26 Feb 2020 19:18:48 +0800 [thread overview]
Message-ID: <20200226111851.55348-5-yuyufen@huawei.com> (raw)
In-Reply-To: <20200226111851.55348-1-yuyufen@huawei.com>
We prepare a new function bdi_get_dev_name() to copy device
kobj->name into buffer passed by caller. The function is covered
by RCU. Thus, caller can access ->dev and copy integral device name.
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
---
include/linux/backing-dev.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 67e429b203a1..89d1cb7923f5 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -514,4 +514,29 @@ static inline const char *bdi_dev_name(struct backing_dev_info *bdi)
return dev_name(&bdi->rcu_dev->dev);
}
+/**
+ * bdi_get_dev_name - copy bdi device name into buffer
+ * @bdi: target bdi
+ * @dname: Where to copy the device name to
+ * @len: size of destination buffer
+ */
+static inline void bdi_get_dev_name(struct backing_dev_info *bdi,
+ char *dname, int len)
+{
+ struct bdi_rcu_device *rcu_dev;
+
+ if (!bdi) {
+ strlcpy(dname, bdi_unknown_name, len);
+ return;
+ }
+
+ rcu_read_lock();
+
+ rcu_dev = rcu_dereference(bdi->rcu_dev);
+ strlcpy(dname, rcu_dev ? dev_name(&rcu_dev->dev) :
+ bdi_unknown_name, len);
+
+ rcu_read_unlock();
+}
+
#endif /* _LINUX_BACKING_DEV_H */
--
2.16.2.dirty
next prev parent reply other threads:[~2020-02-26 11:11 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-26 11:18 [PATCH v2 0/7] bdi: fix use-after-free for bdi device Yufen Yu
2020-02-26 11:18 ` [PATCH v2 1/7] blk-wbt: use bdi_dev_name() to get device name Yufen Yu
2020-02-26 11:18 ` [PATCH v2 2/7] fs/ceph: " Yufen Yu
2020-02-26 11:18 ` [PATCH v2 3/7] bdi: protect device lifetime with RCU Yufen Yu
2020-03-04 17:05 ` Tejun Heo
2020-03-04 17:22 ` Greg Kroah-Hartman
2020-03-04 17:23 ` Greg Kroah-Hartman
2020-03-04 18:50 ` Tejun Heo
2020-03-04 19:10 ` Theodore Y. Ts'o
2020-03-04 19:15 ` Tejun Heo
2020-03-04 20:05 ` Greg Kroah-Hartman
2020-03-05 1:22 ` Tejun Heo
2020-03-06 16:25 ` Greg Kroah-Hartman
2020-03-07 9:13 ` Yufen Yu
2020-02-26 11:18 ` Yufen Yu [this message]
2020-02-26 11:18 ` [PATCH v2 5/7] bfq: fix potential kernel crash when print dev err info Yufen Yu
2020-02-26 11:18 ` [PATCH v2 6/7] memcg: fix crash in wb_workfn when bdi unregister Yufen Yu
2020-02-26 11:18 ` [PATCH v2 7/7] blk-wbt: replace bdi_dev_name() with bdi_get_dev_name() Yufen Yu
2020-03-04 17:29 ` [PATCH v2 0/7] bdi: fix use-after-free for bdi device Greg KH
2020-03-04 18:57 ` Tejun Heo
2020-03-04 20:07 ` Greg KH
2020-03-04 19:02 ` Theodore Y. Ts'o
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