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| author | Tejun Heo <tj@kernel.org> | 2014-02-11 11:52:48 -0500 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2014-02-11 11:52:48 -0500 |
| commit | 5f46990787e2721b4db190ddc8af6fdbe8f010d7 (patch) | |
| tree | 5a5e8439e8560eb95a86f58036b5282e1a7036b6 /block/cfq-iosched.c | |
| parent | de00ffa56ea3132c6013fc8f07133b8a1014cf53 (diff) | |
| download | lwn-5f46990787e2721b4db190ddc8af6fdbe8f010d7.tar.gz lwn-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 'block/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 744833b630c6..461187943392 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1838,7 +1838,6 @@ static struct cftype cfq_blkcg_files[] = { .flags = CFTYPE_ONLY_ON_ROOT, .seq_show = cfqg_print_leaf_weight_device, .write_string = cfqg_set_leaf_weight_device, - .max_write_len = 256, }, { .name = "weight", @@ -1853,7 +1852,6 @@ static struct cftype cfq_blkcg_files[] = { .flags = CFTYPE_NOT_ON_ROOT, .seq_show = cfqg_print_weight_device, .write_string = cfqg_set_weight_device, - .max_write_len = 256, }, { .name = "weight", @@ -1866,7 +1864,6 @@ static struct cftype cfq_blkcg_files[] = { .name = "leaf_weight_device", .seq_show = cfqg_print_leaf_weight_device, .write_string = cfqg_set_leaf_weight_device, - .max_write_len = 256, }, { .name = "leaf_weight", |