From dbeccabf5294e80f7cc9ee566746c42211bed736 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 19 Dec 2017 10:01:47 +1100 Subject: [PATCH] staging: lustre: disable preempt while sampling processor id. 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 Reviewed-by: Andreas Dilger Signed-off-by: Greg Kroah-Hartman --- .../staging/lustre/lnet/libcfs/linux/linux-cpu.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/staging/lustre/lnet/libcfs/linux/linux-cpu.c b/drivers/staging/lustre/lnet/libcfs/linux/linux-cpu.c index ae306c9c3c78..2f5d8f300ef5 100644 --- 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); -- 2.45.2