sysfs.txt: mention that store method buffers are null-terminated

Without knowing this, the use of sysfs_streq() becomes puzzling.

The termination happens in kernfs_fop_write().

Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
[jc: moved the new text to a different paragraph]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Ulf Magnusson 2015-09-07 19:06:14 +02:00 коммит произвёл Jonathan Corbet
Родитель 9ba41327d8
Коммит 17666497fe
1 изменённых файлов: 4 добавлений и 3 удалений

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@ -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.