The patch titled
cgroups: remove some redundant NULL checks
has been added to the -mm tree. Its filename is
cgroups-remove-some-redundant-null-checks.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: cgroups: remove some redundant NULL checks
From: Li Zefan <lizf@xxxxxxxxxxxxxx>
- In cgroup_clone(), if vfs_mkdir() returns successfully,
dentry->d_fsdata will be the pointer to the newly created
cgroup and won't be NULL.
- a cgroup file's dentry->d_fsdata won't be NULL, guaranteed
by cgroup_add_file().
- When walking through the subsystems of a cgroup_fs (using
for_each_subsys), cgrp->subsys[ss->subsys_id] won't be NULL,
guaranteed by cgroup_create().
(Also remove 2 unused variables in cgroup_rmdir().
Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cgroup.c | 29 +++++++----------------------
1 file changed, 7 insertions(+), 22 deletions(-)
diff -puN kernel/cgroup.c~cgroups-remove-some-redundant-null-checks kernel/cgroup.c
--- a/kernel/cgroup.c~cgroups-remove-some-redundant-null-checks
+++ a/kernel/cgroup.c
@@ -587,7 +587,7 @@ static void cgroup_call_pre_destroy(stru
{
struct cgroup_subsys *ss;
for_each_subsys(cgrp->root, ss)
- if (ss->pre_destroy && cgrp->subsys[ss->subsys_id])
+ if (ss->pre_destroy)
ss->pre_destroy(ss, cgrp);
return;
}
@@ -611,10 +611,8 @@ static void cgroup_diput(struct dentry *
/*
* Release the subsystem state objects.
*/
- for_each_subsys(cgrp->root, ss) {
- if (cgrp->subsys[ss->subsys_id])
- ss->destroy(ss, cgrp);
- }
+ for_each_subsys(cgrp->root, ss)
+ ss->destroy(ss, cgrp);
cgrp->root->number_of_cgroups--;
mutex_unlock(&cgroup_mutex);
@@ -1445,7 +1443,7 @@ static ssize_t cgroup_file_write(struct
struct cftype *cft = __d_cft(file->f_dentry);
struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
- if (!cft || cgroup_is_removed(cgrp))
+ if (cgroup_is_removed(cgrp))
return -ENODEV;
if (cft->write)
return cft->write(cgrp, cft, file, buf, nbytes, ppos);
@@ -1490,7 +1488,7 @@ static ssize_t cgroup_file_read(struct f
struct cftype *cft = __d_cft(file->f_dentry);
struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
- if (!cft || cgroup_is_removed(cgrp))
+ if (cgroup_is_removed(cgrp))
return -ENODEV;
if (cft->read)
@@ -1554,10 +1552,8 @@ static int cgroup_file_open(struct inode
err = generic_file_open(inode, file);
if (err)
return err;
-
cft = __d_cft(file->f_dentry);
- if (!cft)
- return -ENODEV;
+
if (cft->read_map || cft->read_seq_string) {
struct cgroup_seqfile_state *state =
kzalloc(sizeof(*state), GFP_USER);
@@ -2463,8 +2459,6 @@ static int cgroup_rmdir(struct inode *un
struct cgroup *cgrp = dentry->d_fsdata;
struct dentry *d;
struct cgroup *parent;
- struct super_block *sb;
- struct cgroupfs_root *root;
/* the vfs holds both inode->i_mutex already */
@@ -2487,8 +2481,6 @@ static int cgroup_rmdir(struct inode *un
mutex_lock(&cgroup_mutex);
parent = cgrp->parent;
- root = cgrp->root;
- sb = root->sb;
if (atomic_read(&cgrp->count)
|| !list_empty(&cgrp->children)
@@ -2936,7 +2928,7 @@ int cgroup_clone(struct task_struct *tsk
}
/* Create the cgroup directory, which also creates the cgroup */
- ret = vfs_mkdir(inode, dentry, S_IFDIR | 0755);
+ ret = vfs_mkdir(inode, dentry, 0755);
child = __d_cgrp(dentry);
dput(dentry);
if (ret) {
@@ -2946,13 +2938,6 @@ int cgroup_clone(struct task_struct *tsk
goto out_release;
}
- if (!child) {
- printk(KERN_INFO
- "Couldn't find new cgroup %s\n", nodename);
- ret = -ENOMEM;
- goto out_release;
- }
-
/* The cgroup now exists. Retake cgroup_mutex and check
* that we're still in the same state that we thought we
* were. */
_
Patches currently in -mm which might be from lizf@xxxxxxxxxxxxxx are
origin.patch
memcg-memory-hotplug-fix-for-notifier-callback.patch
linux-next.patch
oom-print-triggering-tasks-cpuset-and-mems-allowed-fix.patch
cgroups-documentation-updates.patch
cgroups-remove-some-redundant-null-checks.patch
ns_cgroup-remove-unused-spinlock.patch
memcg-fix-a-typo-in-kconfig.patch
memcg-reduce-size-of-mem_cgroup-by-using-nr_cpu_ids.patch
memcg-new-force_empty-to-free-pages-under-group.patch
memcg-handle-swap-caches.patch
memcg-memswap-controller-kconfig.patch
memcg-swap-cgroup-for-remembering-usage.patch
memcg-swap-cgroup-for-remembering-usage-fix.patch
memcg-swap-cgroup-for-remembering-usage-fix-2.patch
memcg-swap-cgroup-for-remembering-usage-fix-3.patch
memcg-swap-cgroup-for-remembering-usage-fix-4.patch
memcg-memswap-controller-core.patch
memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch
memcg-synchronized-lru.patch
memcg-add-mem_cgroup_disabled.patch
memcg-add-mem_cgroup_disabled-fix.patch
memory-cgroup-hierarchy-documentation-v4.patch
memory-cgroup-resource-counters-for-hierarchy-v4.patch
memory-cgroup-resource-counters-for-hierarchy-v4-checkpatch-fixes.patch
memory-cgroup-hierarchical-reclaim-v4.patch
memory-cgroup-hierarchical-reclaim-v4-checkpatch-fixes.patch
memory-cgroup-hierarchy-feature-selector-v4.patch
memory-cgroup-hierarchy-feature-selector-v4-fix.patch
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