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author | Tejun Heo <tj@kernel.org> | 2014-02-11 11:52:48 -0500 |
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committer | Tejun Heo <tj@kernel.org> | 2014-02-11 11:52:48 -0500 |
commit | 5f46990787e2721b4db190ddc8af6fdbe8f010d7 (patch) | |
tree | 5a5e8439e8560eb95a86f58036b5282e1a7036b6 /include/linux/cgroup.h | |
parent | de00ffa56ea3132c6013fc8f07133b8a1014cf53 (diff) | |
download | linux-stable-5f46990787e2721b4db190ddc8af6fdbe8f010d7.tar.gz linux-stable-5f46990787e2721b4db190ddc8af6fdbe8f010d7.tar.bz2 linux-stable-5f46990787e2721b4db190ddc8af6fdbe8f010d7.zip |
cgroup: update the meaning of cftype->max_write_len
cftype->max_write_len is used to extend the maximum size of writes.
It's interpreted in such a way that the actual maximum size is one
less than the specified value. The default size is defined by
CGROUP_LOCAL_BUFFER_SIZE. Its interpretation is quite confusing - its
value is decremented by 1 and then compared for equality with max
size, which means that the actual default size is
CGROUP_LOCAL_BUFFER_SIZE - 2, which is 62 chars.
There's no point in having a limit that low. Update its definition so
that it means the actual string length sans termination and anything
below PAGE_SIZE-1 is treated as PAGE_SIZE-1.
.max_write_len for "release_agent" is updated to PATH_MAX-1 and
cgroup_release_agent_write() is updated so that the redundant strlen()
check is removed and it uses strlcpy() instead of strcpy().
.max_write_len initializations in blk-throttle.c and cfq-iosched.c are
no longer necessary and removed. The one in cpuset is kept unchanged
as it's an approximated value to begin with.
This will also make transition to kernfs smoother.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'include/linux/cgroup.h')
-rw-r--r-- | include/linux/cgroup.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index c4350a82320b..63feaed83bc6 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -400,8 +400,9 @@ struct cftype { umode_t mode; /* - * If non-zero, defines the maximum length of string that can - * be passed to write_string; defaults to 64 + * The maximum length of string, excluding trailing nul, that can + * be passed to write_string. If < PAGE_SIZE-1, PAGE_SIZE-1 is + * assumed. */ size_t max_write_len; |