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cgroup: restructure the failure path in cgroup_write_event_control()

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It uses a single label and checks the validity of each pointer. This
is err-prone, and actually we had a bug because one of the check was
insufficient.

Use multi lables as we do in other places.

v2:
- drop initializations of local variables.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Li Zefan 2013-08-01 09:51:47 +08:00 committed by Tejun Heo
parent e14880f7bb
commit 876ede8b2b
1 changed files with 18 additions and 21 deletions
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39
kernel/cgroup.c
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@ -3934,11 +3934,11 @@ static void cgroup_event_ptable_queue_proc(struct file *file,
static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
const char *buffer)
{
struct cgroup_event *event = NULL;
struct cgroup_event *event;
struct cgroup *cgrp_cfile;
unsigned int efd, cfd;
struct file *efile = NULL;
struct file *cfile = NULL;
struct file *efile;
struct file *cfile;
char *endp;
int ret;
@ -3964,31 +3964,31 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
efile = eventfd_fget(efd);
if (IS_ERR(efile)) {
ret = PTR_ERR(efile);
goto fail;
goto out_kfree;
}
event->eventfd = eventfd_ctx_fileget(efile);
if (IS_ERR(event->eventfd)) {
ret = PTR_ERR(event->eventfd);
goto fail;
goto out_put_efile;
}
cfile = fget(cfd);
if (!cfile) {
ret = -EBADF;
goto fail;
goto out_put_eventfd;
}
/* the process need read permission on control file */
/* AV: shouldn't we check that it's been opened for read instead? */
ret = inode_permission(file_inode(cfile), MAY_READ);
if (ret < 0)
goto fail;
goto out_put_cfile;
event->cft = __file_cft(cfile);
if (IS_ERR(event->cft)) {
ret = PTR_ERR(event->cft);
goto fail;
goto out_put_cfile;
}
/*
@ -3998,18 +3998,18 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
cgrp_cfile = __d_cgrp(cfile->f_dentry->d_parent);
if (cgrp_cfile != cgrp) {
ret = -EINVAL;
goto fail;
goto out_put_cfile;
}
if (!event->cft->register_event || !event->cft->unregister_event) {
ret = -EINVAL;
goto fail;
goto out_put_cfile;
}
ret = event->cft->register_event(cgrp, event->cft,
event->eventfd, buffer);
if (ret)
goto fail;
goto out_put_cfile;
efile->f_op->poll(efile, &event->pt);
@ -4029,16 +4029,13 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
return 0;
fail:
if (cfile)
fput(cfile);
if (event && event->eventfd && !IS_ERR(event->eventfd))
eventfd_ctx_put(event->eventfd);
if (!IS_ERR_OR_NULL(efile))
fput(efile);
out_put_cfile:
fput(cfile);
out_put_eventfd:
eventfd_ctx_put(event->eventfd);
out_put_efile:
fput(efile);
out_kfree:
kfree(event);
return ret;