Messages in this thread Patch in this message | | | Date | Mon, 28 Feb 2011 15:55:24 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] cpuset: Add a missing unlock in cpuset_write_resmask() |
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On Thu, 24 Feb 2011 14:58:58 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote:
> Don't forget to release cgroup_mutex if alloc_trial_cpuset() fails. > > Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> > --- > kernel/cpuset.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/kernel/cpuset.c b/kernel/cpuset.c > index 1ca786a..6272503 100644 > --- a/kernel/cpuset.c > +++ b/kernel/cpuset.c > @@ -1561,8 +1561,10 @@ static int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft, > return -ENODEV; > > trialcs = alloc_trial_cpuset(cs); > - if (!trialcs) > + if (!trialcs) { > + cgroup_unlock(); > return -ENOMEM; > + } > > switch (cft->private) { > case FILE_CPULIST:
It would be better to avoid multiple returns - it leads to more maintainable code and often shorter code:
--- a/kernel/cpuset.c~cpuset-add-a-missing-unlock-in-cpuset_write_resmask-fix +++ a/kernel/cpuset.c @@ -1562,8 +1562,8 @@ static int cpuset_write_resmask(struct c trialcs = alloc_trial_cpuset(cs); if (!trialcs) { - cgroup_unlock(); - return -ENOMEM; + retval = -ENOMEM; + goto out; } switch (cft->private) { @@ -1579,6 +1579,7 @@ static int cpuset_write_resmask(struct c } free_trial_cpuset(trialcs); +out: cgroup_unlock(); return retval; } _ also, alloc_trial_cpuset() is a fairly slow-looking function. cpuset_write_resmask() could run alloc_trial_cpuset() before running cgroup_lock_live_group(), thereby reducing lock hold times.
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