From: Tejun Heo <tj@kernel.org>
To: davem@davemloft.net, pablo@netfilter.org, kaber@trash.net,
kadlec@blackhole.kfki.hu, daniel@iogearbox.net,
daniel.wagner@bmw-carit.de, nhorman@tuxdriver.com
Cc: lizefan@huawei.com, hannes@cmpxchg.org, netdev@vger.kernel.org,
netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, ninasc@fb.com, Tejun Heo <tj@kernel.org>
Subject: [PATCH 2/8] kernfs: implement kernfs_walk_and_get()
Date: Mon, 7 Dec 2015 17:38:49 -0500 [thread overview]
Message-ID: <1449527935-27056-3-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1449527935-27056-1-git-send-email-tj@kernel.org>
Implement kernfs_walk_and_get() which is similar to
kernfs_find_and_get() but can walk a path instead of just a name.
v2: Use strlcpy() instead of strlen() + memcpy() as suggested by
David.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: David Miller <davem@davemloft.net>
---
fs/kernfs/dir.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/kernfs.h | 12 ++++++++++++
2 files changed, 58 insertions(+)
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 91e0045..742bf4a 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -694,6 +694,29 @@ static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
return NULL;
}
+static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
+ const unsigned char *path,
+ const void *ns)
+{
+ static char path_buf[PATH_MAX]; /* protected by kernfs_mutex */
+ size_t len = strlcpy(path_buf, path, PATH_MAX);
+ char *p = path_buf;
+ char *name;
+
+ lockdep_assert_held(&kernfs_mutex);
+
+ if (len >= PATH_MAX)
+ return NULL;
+
+ while ((name = strsep(&p, "/")) && parent) {
+ if (*name == '\0')
+ continue;
+ parent = kernfs_find_ns(parent, name, ns);
+ }
+
+ return parent;
+}
+
/**
* kernfs_find_and_get_ns - find and get kernfs_node with the given name
* @parent: kernfs_node to search under
@@ -719,6 +742,29 @@ struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
/**
+ * kernfs_walk_and_get_ns - find and get kernfs_node with the given path
+ * @parent: kernfs_node to search under
+ * @path: path to look for
+ * @ns: the namespace tag to use
+ *
+ * Look for kernfs_node with path @path under @parent and get a reference
+ * if found. This function may sleep and returns pointer to the found
+ * kernfs_node on success, %NULL on failure.
+ */
+struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
+ const char *path, const void *ns)
+{
+ struct kernfs_node *kn;
+
+ mutex_lock(&kernfs_mutex);
+ kn = kernfs_walk_ns(parent, path, ns);
+ kernfs_get(kn);
+ mutex_unlock(&kernfs_mutex);
+
+ return kn;
+}
+
+/**
* kernfs_create_root - create a new kernfs hierarchy
* @scops: optional syscall operations for the hierarchy
* @flags: KERNFS_ROOT_* flags
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 5d4e9c4..af51df3 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -274,6 +274,8 @@ void pr_cont_kernfs_path(struct kernfs_node *kn);
struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn);
struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
const char *name, const void *ns);
+struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
+ const char *path, const void *ns);
void kernfs_get(struct kernfs_node *kn);
void kernfs_put(struct kernfs_node *kn);
@@ -350,6 +352,10 @@ static inline struct kernfs_node *
kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
const void *ns)
{ return NULL; }
+static inline struct kernfs_node *
+kernfs_walk_and_get_ns(struct kernfs_node *parent, const char *path,
+ const void *ns)
+{ return NULL; }
static inline void kernfs_get(struct kernfs_node *kn) { }
static inline void kernfs_put(struct kernfs_node *kn) { }
@@ -431,6 +437,12 @@ kernfs_find_and_get(struct kernfs_node *kn, const char *name)
}
static inline struct kernfs_node *
+kernfs_walk_and_get(struct kernfs_node *kn, const char *path)
+{
+ return kernfs_walk_and_get_ns(kn, path, NULL);
+}
+
+static inline struct kernfs_node *
kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode,
void *priv)
{
--
2.5.0
next prev parent reply other threads:[~2015-12-07 22:38 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-07 22:38 [PATCHSET v4] netfilter, cgroup: implement cgroup2 path match in xt_cgroup Tejun Heo
2015-12-07 22:38 ` [PATCH 1/8] cgroup: record ancestor IDs and reimplement cgroup_is_descendant() using it Tejun Heo
2015-12-07 22:38 ` Tejun Heo [this message]
[not found] ` <1449527935-27056-3-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2016-01-15 12:29 ` [PATCH 2/8] kernfs: implement kernfs_walk_and_get() Geert Uytterhoeven
2016-01-15 17:30 ` [PATCH] kernfs: make kernfs_walk_ns() use kernfs_pr_cont_buf[] Tejun Heo
[not found] ` <20160115173014.GI3520-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2016-01-15 22:05 ` Greg Kroah-Hartman
[not found] ` <1449527935-27056-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-12-07 22:38 ` [PATCH 3/8] cgroup: implement cgroup_get_from_path() and expose cgroup_put() Tejun Heo
[not found] ` <1449527935-27056-4-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2015-12-22 0:22 ` Serge E. Hallyn
2015-12-22 18:13 ` Tejun Heo
2015-12-07 22:38 ` [PATCH 4/8] netprio_cgroup: limit the maximum css->id to USHRT_MAX Tejun Heo
2015-12-09 3:03 ` [PATCHSET v4] netfilter, cgroup: implement cgroup2 path match in xt_cgroup David Miller
2015-12-07 22:38 ` [PATCH 5/8] net: wrap sock->sk_cgrp_prioidx and ->sk_classid inside a struct Tejun Heo
2015-12-07 22:38 ` [PATCH 6/8] sock, cgroup: add sock->sk_cgroup Tejun Heo
2015-12-07 22:38 ` [PATCH 7/8] netfilter: prepare xt_cgroup for multi revisions Tejun Heo
2015-12-14 19:35 ` Pablo Neira Ayuso
2015-12-07 22:38 ` [PATCH 8/8] netfilter: implement xt_cgroup cgroup2 path match Tejun Heo
2015-12-14 19:37 ` Pablo Neira Ayuso
[not found] ` <1449527935-27056-9-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2016-02-12 0:10 ` Alban Crequy
[not found] ` <CAMXgnP7Eue2NQrUcRSNgM8NJT5XOscPWwqVkuh7LnwQn-1oQ_A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-02-12 16:05 ` Tejun Heo
2015-12-14 11:54 ` [PATCHSET v4] netfilter, cgroup: implement cgroup2 path match in xt_cgroup Dexuan Cui
2015-12-14 16:24 ` [PATCH net-next] net, cgroup: cgroup_sk_updat_lock was missing initializer Tejun Heo
2015-12-14 19:20 ` David Miller
[not found] ` <20151214.142043.1185024338854399910.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2015-12-15 2:11 ` Dexuan Cui
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