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authorTejun Heo <tj@kernel.org>2014-02-11 11:52:48 -0500
committerTejun Heo <tj@kernel.org>2014-02-11 11:52:48 -0500
commit5f46990787e2721b4db190ddc8af6fdbe8f010d7 (patch)
tree5a5e8439e8560eb95a86f58036b5282e1a7036b6 /block
parentde00ffa56ea3132c6013fc8f07133b8a1014cf53 (diff)
downloadlinux-5f46990787e2721b4db190ddc8af6fdbe8f010d7.tar.gz
linux-5f46990787e2721b4db190ddc8af6fdbe8f010d7.tar.xz
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')
-rw-r--r--block/blk-throttle.c4
-rw-r--r--block/cfq-iosched.c3
2 files changed, 0 insertions, 7 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 1474c3a..861c363 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1425,28 +1425,24 @@ static struct cftype throtl_files[] = {
.private = offsetof(struct throtl_grp, bps[READ]),
.seq_show = tg_print_conf_u64,
.write_string = tg_set_conf_u64,
- .max_write_len = 256,
},
{
.name = "throttle.write_bps_device",
.private = offsetof(struct throtl_grp, bps[WRITE]),
.seq_show = tg_print_conf_u64,
.write_string = tg_set_conf_u64,
- .max_write_len = 256,
},
{
.name = "throttle.read_iops_device",
.private = offsetof(struct throtl_grp, iops[READ]),
.seq_show = tg_print_conf_uint,
.write_string = tg_set_conf_uint,
- .max_write_len = 256,
},
{
.name = "throttle.write_iops_device",
.private = offsetof(struct throtl_grp, iops[WRITE]),
.seq_show = tg_print_conf_uint,
.write_string = tg_set_conf_uint,
- .max_write_len = 256,
},
{
.name = "throttle.io_service_bytes",
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 744833b..4611879 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",