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    SubjectRe: [PATCH 1/2] pm_qos: remove BKL
    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
    >
    > --
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