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| author | Paul Menage <menage@google.com> | 2007-10-19 08:39:33 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-19 20:53:36 +0200 |
| commit | 355e0c48b757b7fcc79ccb98fda8105ed37a1598 (patch) | |
| tree | f9687961979a808e46620f4bdf9af05de2fd68e2 /kernel | |
| parent | Task Control Groups: add tasks file interface (diff) | |
| download | linux-355e0c48b757b7fcc79ccb98fda8105ed37a1598.tar.xz linux-355e0c48b757b7fcc79ccb98fda8105ed37a1598.zip | |
Add cgroup write_uint() helper method
Add write_uint() helper method for cgroup subsystems
This helper is analagous to the read_uint() helper method for
reporting u64 values to userspace. It's designed to reduce the amount
of boilerplate requierd for creating new cgroup subsystems.
Signed-off-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 42 |
1 files changed, 38 insertions, 4 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 356c40d5d20a..f4c4dce9558f 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -829,6 +829,39 @@ enum cgroup_filetype { FILE_TASKLIST, }; +static ssize_t cgroup_write_uint(struct cgroup *cont, struct cftype *cft, + struct file *file, + const char __user *userbuf, + size_t nbytes, loff_t *unused_ppos) +{ + char buffer[64]; + int retval = 0; + u64 val; + char *end; + + if (!nbytes) + return -EINVAL; + if (nbytes >= sizeof(buffer)) + return -E2BIG; + if (copy_from_user(buffer, userbuf, nbytes)) + return -EFAULT; + + buffer[nbytes] = 0; /* nul-terminate */ + + /* strip newline if necessary */ + if (nbytes && (buffer[nbytes-1] == '\n')) + buffer[nbytes-1] = 0; + val = simple_strtoull(buffer, &end, 0); + if (*end) + return -EINVAL; + + /* Pass to subsystem */ + retval = cft->write_uint(cont, cft, val); + if (!retval) + retval = nbytes; + return retval; +} + static ssize_t cgroup_common_file_write(struct cgroup *cont, struct cftype *cft, struct file *file, @@ -886,10 +919,11 @@ static ssize_t cgroup_file_write(struct file *file, const char __user *buf, if (!cft) return -ENODEV; - if (!cft->write) - return -EINVAL; - - return cft->write(cont, cft, file, buf, nbytes, ppos); + if (cft->write) + return cft->write(cont, cft, file, buf, nbytes, ppos); + if (cft->write_uint) + return cgroup_write_uint(cont, cft, file, buf, nbytes, ppos); + return -EINVAL; } static ssize_t cgroup_read_uint(struct cgroup *cont, struct cftype *cft, |