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authorMauro Carvalho Chehab <mchehab+huawei@kernel.org>2020-04-27 23:17:18 +0200
committerJonathan Corbet <corbet@lwn.net>2020-05-05 09:22:24 -0600
commitec4551f45036d23a34d4f13ab3ce2ea345a13de7 (patch)
tree66a708f8ab960d17a842e5916a2a5c1110c8e883 /Documentation
parent28bcadf0ae994fd3584f43c39b6915ee70b59749 (diff)
downloadlwn-ec4551f45036d23a34d4f13ab3ce2ea345a13de7.tar.gz
lwn-ec4551f45036d23a34d4f13ab3ce2ea345a13de7.zip
docs: filesystems: convert sysfs-tagging.txt to ReST
- Add a SPDX header; - Adjust document title; - Some whitespace fixes and new line breaks; - Mark literal blocks as such; - Add it to filesystems/index.rst. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/45a01fa5edd5c6ee8fc0754fc74f7ef65a3e5581.1588021877.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/index.rst1
-rw-r--r--Documentation/filesystems/sysfs-tagging.rst (renamed from Documentation/filesystems/sysfs-tagging.txt)22
2 files changed, 15 insertions, 8 deletions
diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst
index 7afb58dff43b..14e298d84c8a 100644
--- a/Documentation/filesystems/index.rst
+++ b/Documentation/filesystems/index.rst
@@ -35,6 +35,7 @@ algorithms work.
seq_file
sharedsubtree
sysfs-pci
+ sysfs-tagging
automount-support
diff --git a/Documentation/filesystems/sysfs-tagging.txt b/Documentation/filesystems/sysfs-tagging.rst
index c7c8e6438958..8888a05c398e 100644
--- a/Documentation/filesystems/sysfs-tagging.txt
+++ b/Documentation/filesystems/sysfs-tagging.rst
@@ -1,5 +1,8 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============
Sysfs tagging
--------------
+=============
(Taken almost verbatim from Eric Biederman's netns tagging patch
commit msg)
@@ -18,25 +21,28 @@ in the directories and applications only see a limited set of
the network devices.
Each sysfs directory entry may be tagged with a namespace via the
-void *ns member of its kernfs_node. If a directory entry is tagged,
-then kernfs_node->flags will have a flag between KOBJ_NS_TYPE_NONE
+``void *ns member`` of its ``kernfs_node``. If a directory entry is tagged,
+then ``kernfs_node->flags`` will have a flag between KOBJ_NS_TYPE_NONE
and KOBJ_NS_TYPES, and ns will point to the namespace to which it
belongs.
-Each sysfs superblock's kernfs_super_info contains an array void
-*ns[KOBJ_NS_TYPES]. When a task in a tagging namespace
+Each sysfs superblock's kernfs_super_info contains an array
+``void *ns[KOBJ_NS_TYPES]``. When a task in a tagging namespace
kobj_nstype first mounts sysfs, a new superblock is created. It
will be differentiated from other sysfs mounts by having its
-s_fs_info->ns[kobj_nstype] set to the new namespace. Note that
+``s_fs_info->ns[kobj_nstype]`` set to the new namespace. Note that
through bind mounting and mounts propagation, a task can easily view
the contents of other namespaces' sysfs mounts. Therefore, when a
namespace exits, it will call kobj_ns_exit() to invalidate any
kernfs_node->ns pointers pointing to it.
Users of this interface:
-- define a type in the kobj_ns_type enumeration.
-- call kobj_ns_type_register() with its kobj_ns_type_operations which has
+
+- define a type in the ``kobj_ns_type`` enumeration.
+- call kobj_ns_type_register() with its ``kobj_ns_type_operations`` which has
+
- current_ns() which returns current's namespace
- netlink_ns() which returns a socket's namespace
- initial_ns() which returns the initial namesapce
+
- call kobj_ns_exit() when an individual tag is no longer valid