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staging: lustre: disable preempt while sampling processor id.

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[ Upstream commit dbeccabf52 ]

Calling smp_processor_id() without disabling preemption
triggers a warning (if CONFIG_DEBUG_PREEMPT).
I think the result of cfs_cpt_current() is only used as a hint for
load balancing, rather than as a precise and stable indicator of
the current CPU.  So it doesn't need to be called with
preemption disabled.

So disable preemption inside cfs_cpt_current() to silence the warning.

Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
NeilBrown
2017-12-19 10:01:47 +11:00
committed by Greg Kroah-Hartman
parent 01ff15fcf4
commit 89deb4ad01
1 changed files with 7 additions and 6 deletions
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13
drivers/staging/lustre/lnet/libcfs/linux/linux-cpu.c
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@@ -528,19 +528,20 @@ EXPORT_SYMBOL(cfs_cpt_spread_node);
int
cfs_cpt_current(struct cfs_cpt_table *cptab, int remap)
{
int cpu = smp_processor_id();
int cpt = cptab->ctb_cpu2cpt[cpu];
int cpu;
int cpt;
if (cpt < 0) {
if (!remap)
return cpt;
preempt_disable();
cpu = smp_processor_id();
cpt = cptab->ctb_cpu2cpt[cpu];
if (cpt < 0 && remap) {
/* don't return negative value for safety of upper layer,
* instead we shadow the unknown cpu to a valid partition ID
*/
cpt = cpu % cptab->ctb_nparts;
}
preempt_enable();
return cpt;
}
EXPORT_SYMBOL(cfs_cpt_current);