From: Bart Van Assche bvanassche@acm.org
mainline inclusion from mainline-v5.13-rc1 commit 035e9f471691a16c32b389c8b2f236043a2a50d7 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IB4C27
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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All sbitmap code uses implied preemption protection to update sb->alloc_hint except sbitmap_put(). Using implied preemption protection is safe since the value of sb->alloc_hint only affects performance of sbitmap allocations but not their correctness. Change this_cpu_ptr() in sbitmap_put() into raw_cpu_ptr() to suppress the following kernel warning that appears with preemption debugging enabled (CONFIG_DEBUG_PREEMPT):
BUG: using smp_processor_id() in preemptible [00000000] code: scsi_eh_0/152 caller is debug_smp_processor_id+0x17/0x20 CPU: 1 PID: 152 Comm: scsi_eh_0 Tainted: G W 5.12.0-rc1-dbg+ #6 Call Trace: show_stack+0x52/0x58 dump_stack+0xaf/0xf3 check_preemption_disabled+0xce/0xd0 debug_smp_processor_id+0x17/0x20 scsi_device_unbusy+0x13a/0x1c0 [scsi_mod] scsi_finish_command+0x4d/0x290 [scsi_mod] scsi_eh_flush_done_q+0x1e7/0x280 [scsi_mod] ata_scsi_port_error_handler+0x592/0x750 [libata] ata_scsi_error+0x1a0/0x1f0 [libata] scsi_error_handler+0x19e/0x330 [scsi_mod] kthread+0x222/0x250 ret_from_fork+0x1f/0x30
Link: https://lore.kernel.org/r/20210317032648.9080-1-bvanassche@acm.org Fixes: c548e62bcf6a ("scsi: sbitmap: Move allocation hint into sbitmap") Cc: Hannes Reinecke hare@suse.de Cc: Omar Sandoval osandov@fb.com Reviewed-by: Ming Lei ming.lei@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Zheng Qixing zhengqixing@huawei.com --- include/linux/sbitmap.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h index 9208ccbed720..c1db875f77f8 100644 --- a/include/linux/sbitmap.h +++ b/include/linux/sbitmap.h @@ -332,7 +332,7 @@ static inline void sbitmap_put(struct sbitmap *sb, unsigned int bitnr) sbitmap_deferred_clear_bit(sb, bitnr);
if (likely(sb->alloc_hint && !sb->round_robin && bitnr < sb->depth)) - *this_cpu_ptr(sb->alloc_hint) = bitnr; + *raw_cpu_ptr(sb->alloc_hint) = bitnr; }
static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr)