diff options
| author | Paul Menage <menage@google.com> | 2008-07-25 01:46:58 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-25 10:53:35 -0700 |
| commit | db3b14978abc02041046ed8353f0899cb58ffffc (patch) | |
| tree | 355ba027c6354bd13bcbb5318e8478b3de4599e9 /include/linux | |
| parent | ce16b49d37e748574f7fabc2726268d542d0aa1a (diff) | |
cgroup files: add write_string cgroup control file method
This patch adds a write_string() method for cgroups control files. The
semantics are that a buffer is copied from userspace to kernelspace
and the handler function invoked on that buffer. The buffer is
guaranteed to be nul-terminated, and no longer than max_write_len
(defaulting to 64 bytes if unspecified). Later patches will convert
existing raw file write handlers in control group subsystems to use
this method.
Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Balbir Singh <balbir@in.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/cgroup.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 88a734edccb..f5379455bb5 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -205,6 +205,13 @@ struct cftype { * subsystem, followed by a period */ char name[MAX_CFTYPE_NAME]; int private; + + /* + * If non-zero, defines the maximum length of string that can + * be passed to write_string; defaults to 64 + */ + size_t max_write_len; + int (*open)(struct inode *inode, struct file *file); ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft, struct file *file, @@ -249,6 +256,13 @@ struct cftype { int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val); /* + * write_string() is passed a nul-terminated kernelspace + * buffer of maximum length determined by max_write_len. + * Returns 0 or -ve error code. + */ + int (*write_string)(struct cgroup *cgrp, struct cftype *cft, + const char *buffer); + /* * trigger() callback can be used to get some kick from the * userspace, when the actual string written is not important * at all. The private field can be used to determine the |