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| author | Tejun Heo <tj@kernel.org> | 2014-11-18 02:49:50 -0500 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2014-11-18 02:49:50 -0500 |
| commit | 755bf5ee8633b97d8fd0ffbb4221662056dda22b (patch) | |
| tree | 5b2a32ce799333ccf8db0a7ffdc0e0df7be2e695 /kernel/cgroup.c | |
| parent | 0f060deb5c5107486c5dadd5c715b3693d381e0a (diff) | |
| download | linux-755bf5ee8633b97d8fd0ffbb4221662056dda22b.tar.gz linux-755bf5ee8633b97d8fd0ffbb4221662056dda22b.tar.bz2 linux-755bf5ee8633b97d8fd0ffbb4221662056dda22b.zip | |
cgroup: restructure child_subsys_mask handling in cgroup_subtree_control_write()
Make cgroup_subtree_control_write() first calculate new
subtree_control (new_sc), child_subsys_mask (new_ss) and
css_enable/disable masks before applying them to the cgroup. Also,
store the original subtree_control (old_sc) and child_subsys_mask
(old_ss) and use them to restore the orignal state after failure.
This patch shouldn't cause any behavior changes. This prepares for a
fix for a bug in the async css offline wait logic.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 1dda601ec337..cbbb46f783de 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2653,7 +2653,7 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, loff_t off) { unsigned int enable = 0, disable = 0; - unsigned int css_enable, css_disable, old_ctrl, new_ctrl; + unsigned int css_enable, css_disable, old_sc, new_sc, old_ss, new_ss; struct cgroup *cgrp, *child; struct cgroup_subsys *ss; char *tok; @@ -2770,18 +2770,19 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, * subsystems than specified may need to be enabled or disabled * depending on subsystem dependencies. */ - cgrp->subtree_control |= enable; - cgrp->subtree_control &= ~disable; + old_sc = cgrp->subtree_control; + old_ss = cgrp->child_subsys_mask; + new_sc = (old_sc | enable) & ~disable; + new_ss = cgroup_calc_child_subsys_mask(cgrp, new_sc); - old_ctrl = cgrp->child_subsys_mask; - cgroup_refresh_child_subsys_mask(cgrp); - new_ctrl = cgrp->child_subsys_mask; - - css_enable = ~old_ctrl & new_ctrl; - css_disable = old_ctrl & ~new_ctrl; + css_enable = ~old_ss & new_ss; + css_disable = old_ss & ~new_ss; enable |= css_enable; disable |= css_disable; + cgrp->subtree_control = new_sc; + cgrp->child_subsys_mask = new_ss; + /* * Create new csses or make the existing ones visible. A css is * created invisible if it's being implicitly enabled through @@ -2844,9 +2845,8 @@ out_unlock: return ret ?: nbytes; err_undo_css: - cgrp->subtree_control &= ~enable; - cgrp->subtree_control |= disable; - cgroup_refresh_child_subsys_mask(cgrp); + cgrp->subtree_control = old_sc; + cgrp->child_subsys_mask = old_ss; for_each_subsys(ss, ssid) { if (!(enable & (1 << ssid))) |