4.15-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown neilb@suse.com
[ Upstream commit dbeccabf5294e80f7cc9ee566746c42211bed736 ]
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 --- drivers/staging/lustre/lnet/libcfs/linux/linux-cpu.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
--- a/drivers/staging/lustre/lnet/libcfs/linux/linux-cpu.c +++ b/drivers/staging/lustre/lnet/libcfs/linux/linux-cpu.c @@ -529,19 +529,20 @@ 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);