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authorLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 20:44:29 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 20:44:29 -0800
commitb07039b79c9ea64c1eacda1e01d645082e4a0d5d (patch)
tree61532ba8425fdf897d6a67a74391a1c6f322a07b /Documentation
parent02061181d3a9ccfe15ef6bc15fa56283acc47620 (diff)
parent16df1456aa858a86f398dbc7d27649eb6662b0cc (diff)
downloadlwn-b07039b79c9ea64c1eacda1e01d645082e4a0d5d.tar.gz
lwn-b07039b79c9ea64c1eacda1e01d645082e4a0d5d.zip
Merge tag 'driver-core-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH: "Here is the "big" set of driver core patches for 4.21-rc1. It's not really big, just a number of small changes for some reported issues, some documentation updates to hopefully make it harder for people to abuse the driver model, and some other minor cleanups. All of these have been in linux-next for a while with no reported issues" * tag 'driver-core-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: mm, memory_hotplug: update a comment in unregister_memory() component: convert to DEFINE_SHOW_ATTRIBUTE sysfs: Disable lockdep for driver bind/unbind files driver core: Add missing dev->bus->need_parent_lock checks kobject: return error code if writing /sys/.../uevent fails driver core: Move async_synchronize_full call driver core: platform: Respect return code of platform_device_register_full() kref/kobject: Improve documentation drivers/base/memory.c: Use DEVICE_ATTR_RO and friends driver core: Replace simple_strto{l,ul} by kstrtou{l,ul} kernfs: Improve kernfs_notify() poll notification latency kobject: Fix warnings in lib/kobject_uevent.c kobject: drop unnecessary cast "%llu" for u64 driver core: fix comments for device_block_probing() driver core: Replace simple_strtol by kstrtoint
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kobject.txt10
1 files changed, 7 insertions, 3 deletions
diff --git a/Documentation/kobject.txt b/Documentation/kobject.txt
index fc9485d79061..ff4c25098119 100644
--- a/Documentation/kobject.txt
+++ b/Documentation/kobject.txt
@@ -279,10 +279,14 @@ such a method has a form like::
One important point cannot be overstated: every kobject must have a
release() method, and the kobject must persist (in a consistent state)
until that method is called. If these constraints are not met, the code is
-flawed. Note that the kernel will warn you if you forget to provide a
+flawed. Note that the kernel will warn you if you forget to provide a
release() method. Do not try to get rid of this warning by providing an
-"empty" release function; you will be mocked mercilessly by the kobject
-maintainer if you attempt this.
+"empty" release function.
+
+If all your cleanup function needs to do is call kfree(), then you must
+create a wrapper function which uses container_of() to upcast to the correct
+type (as shown in the example above) and then calls kfree() on the overall
+structure.
Note, the name of the kobject is available in the release function, but it
must NOT be changed within this callback. Otherwise there will be a memory