The patch titled
devscgroup: relax task to dev_cgroup conversion
has been added to the -mm tree. Its filename is
devscgroup-relax-task-to-dev_cgroup-conversion.patch
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Subject: devscgroup: relax task to dev_cgroup conversion
From: Pavel Emelyanov <xemul@xxxxxxxxxx>
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To: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Serge Hallyn <serue@xxxxxxxxxx>, Paul Menage <menage@xxxxxxxxxx>,
Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>
Subject: [PATCH 2/2] devscgroup: relax task to dev_cgroup conversion
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Two functions, that need to get a device_cgroup from a task (they
are devcgroup_inode_permission and devcgroup_inode_mknod) make it
in a strange way:
They get a css_set from task, then a subsys_state from css_set,
then a cgroup from the state and then a subsys_state again from
the cgroup. Besides, the devices_subsys_id is read from memory,
whilst there's a enum-ed constant for it.
Optimize this part a bit:
1. Get the subsys_stats form the task and be done - no 2 extra
dereferences,
2. Use the device_subsys_id constant, not the value from memory
(i.e. one less dereference).
Found while preparing 2.6.26 OpenVZ port.
Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxx>
---
security/device_cgroup.c | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 15f2f80..f9941a7 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -506,7 +506,6 @@ struct cgroup_subsys devices_subsys = {
int devcgroup_inode_permission(struct inode *inode, int mask)
{
- struct cgroup *cgroup;
struct dev_cgroup *dev_cgroup;
struct dev_whitelist_item *wh;
@@ -515,8 +514,8 @@ int devcgroup_inode_permission(struct inode *inode, int mask)
return 0;
if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode))
return 0;
- cgroup = task_cgroup(current, devices_subsys.subsys_id);
- dev_cgroup = cgroup_to_devcgroup(cgroup);
+ dev_cgroup = css_to_devcgroup(task_subsys_state(current,
+ devices_subsys_id));
if (!dev_cgroup)
return 0;
@@ -547,12 +546,11 @@ acc_check:
int devcgroup_inode_mknod(int mode, dev_t dev)
{
- struct cgroup *cgroup;
struct dev_cgroup *dev_cgroup;
struct dev_whitelist_item *wh;
- cgroup = task_cgroup(current, devices_subsys.subsys_id);
- dev_cgroup = cgroup_to_devcgroup(cgroup);
+ dev_cgroup = css_to_devcgroup(task_subsys_state(current,
+ devices_subsys_id));
if (!dev_cgroup)
return 0;
--
1.5.3.4
Patches currently in -mm which might be from xemul@xxxxxxxxxx are
linux-next.patch
proc-calculate-the-correct-proc-pid-link-count.patch
proc-calculate-the-correct-proc-pid-link-count-cleanup.patch
mark-res_counter_charge_locked-with-__must_check.patch
memcg-make-global-var-read_mostly.patch
memcg-avoid-unnecessary-initialization.patch
memcg-better-migration-handling.patch
memcg-remove-refcnt-from-page_cgroup.patch
memcg-remove-refcnt-from-page_cgroup-fix.patch
memcg-handle-swap-cache.patch
memcg-helper-function-for-relcaim-from-shmem.patch
memcg-add-hints-for-branch.patch
memcg-remove-a-redundant-check.patch
memrlimit-add-memrlimit-controller-documentation.patch
memrlimit-setup-the-memrlimit-controller.patch
memrlimit-cgroup-mm-owner-callback-changes-to-add-task-info.patch
memrlimit-add-memrlimit-controller-accounting-and-control.patch
devcgroup-make-a-helper-to-convert-cgroup_subsys_state-to-devs_cgroup.patch
devscgroup-relax-task-to-dev_cgroup-conversion.patch
sysctl-allow-override-of-proc-sys-net-with-cap_net_admin.patch
bsdacct-rename-acct_blbls-to-bsd_acct_struct.patch
pidns-use-kzalloc-when-allocating-new-pid_namespace-struct.patch
pidns-add-the-struct-bsd_acct_struct-pointer-on-pid_namespace-struct.patch
bsdacct-truthify-a-comment-near-acct_process.patch
bsdacct-make-check-timer-accept-a-bsd_acct_struct-argument.patch
bsdacct-turn-the-acct_lock-from-on-the-struct-to-global.patch
bsdacct-make-internal-code-work-with-passed-bsd_acct_struct-not-global.patch
bsdacct-switch-from-global-bsd_acct_struct-instance-to-per-pidns-one.patch
bsdacct-turn-acct-off-for-all-pidns-s-on-umount-time.patch
bsdacct-account-dying-tasks-in-all-relevant-namespaces.patch
bsdacct-stir-up-comments-around-acct_process.patch
reiser4.patch
--
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