Messages in this thread | | | Date | Fri, 7 Aug 2009 04:03:32 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 1/2] pm_qos: remove BKL |
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On Thu, Aug 06, 2009 at 01:59:53PM -0600, Jonathan Corbet wrote: > pm_qos_power_open got its lock_kernel() calls from the open() pushdown. A > look at the code shows that the only global resources accessed are > pm_qos_array and "name". pm_qos_array doesn't change (things pointed to > therein do change, but they are atomics and/or are protected by > pm_qos_lock). Accesses to "name" are totally unprotected with or without > the BKL; that will be fixed shortly. The BKL is not helpful here; take it > out. > > Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Is there a 2/2 missing patch in the series, or may be I missed it. I guess it fixes the racy "name"...
> --- > kernel/pm_qos_params.c | 8 +------- > 1 files changed, 1 insertions(+), 7 deletions(-) > > diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c > index dfdec52..d96b83e 100644 > --- a/kernel/pm_qos_params.c > +++ b/kernel/pm_qos_params.c > @@ -29,7 +29,6 @@ > > #include <linux/pm_qos_params.h> > #include <linux/sched.h> > -#include <linux/smp_lock.h> > #include <linux/spinlock.h> > #include <linux/slab.h> > #include <linux/time.h> > @@ -352,20 +351,15 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp) > int ret; > long pm_qos_class; > > - lock_kernel(); > pm_qos_class = find_pm_qos_object_by_minor(iminor(inode)); > if (pm_qos_class >= 0) { > filp->private_data = (void *)pm_qos_class; > sprintf(name, "process_%d", current->pid); > ret = pm_qos_add_requirement(pm_qos_class, name, > PM_QOS_DEFAULT_VALUE); > - if (ret >= 0) { > - unlock_kernel(); > + if (ret >= 0) > return 0; > - } > } > - unlock_kernel(); > - > return -EPERM; > } > > -- > 1.6.2.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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