summaryrefslogtreecommitdiffstats
path: root/kernel/Documentation/filesystems/sysfs.txt
diff options
context:
space:
mode:
authorJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-04-11 10:41:07 +0300
committerJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-04-13 08:17:18 +0300
commite09b41010ba33a20a87472ee821fa407a5b8da36 (patch)
treed10dc367189862e7ca5c592f033dc3726e1df4e3 /kernel/Documentation/filesystems/sysfs.txt
parentf93b97fd65072de626c074dbe099a1fff05ce060 (diff)
These changes are the raw update to linux-4.4.6-rt14. Kernel sources
are taken from kernel.org, and rt patch from the rt wiki download page. During the rebasing, the following patch collided: Force tick interrupt and get rid of softirq magic(I70131fb85). Collisions have been removed because its logic was found on the source already. Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769 Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>
Diffstat (limited to 'kernel/Documentation/filesystems/sysfs.txt')
-rw-r--r--kernel/Documentation/filesystems/sysfs.txt14
1 files changed, 9 insertions, 5 deletions
diff --git a/kernel/Documentation/filesystems/sysfs.txt b/kernel/Documentation/filesystems/sysfs.txt
index b35a64b82..24da7b32c 100644
--- a/kernel/Documentation/filesystems/sysfs.txt
+++ b/kernel/Documentation/filesystems/sysfs.txt
@@ -40,7 +40,7 @@ ancestors of object hierarchies; i.e. the subsystems the objects
belong to.
Sysfs internally stores a pointer to the kobject that implements a
-directory in the sysfs_dirent object associated with the directory. In
+directory in the kernfs_node object associated with the directory. In
the past this kobject pointer has been used by sysfs to do reference
counting directly on the kobject whenever the file is opened or closed.
With the current sysfs implementation the kobject reference count is
@@ -191,9 +191,10 @@ implementations:
be called again, rearmed, to fill the buffer.
- On write(2), sysfs expects the entire buffer to be passed during the
- first write. Sysfs then passes the entire buffer to the store()
- method.
-
+ first write. Sysfs then passes the entire buffer to the store() method.
+ A terminating null is added after the data on stores. This makes
+ functions like sysfs_streq() safe to use.
+
When writing sysfs files, userspace processes should first read the
entire file, modify the values it wishes to change, then write the
entire buffer back.
@@ -212,7 +213,10 @@ Other notes:
- show() methods should return the number of bytes printed into the
buffer. This is the return value of scnprintf().
-- show() should always use scnprintf().
+- show() must not use snprintf() when formatting the value to be
+ returned to user space. If you can guarantee that an overflow
+ will never happen you can use sprintf() otherwise you must use
+ scnprintf().
- store() should return the number of bytes used from the buffer. If the
entire buffer has been used, just return the count argument.