blk-mq: remove the get_cpu/put_cpu pair in blk_mq_complete_request

We don't really care if we get migrated during the I/O completion.
In the worth case we either perform an IPI that wasn't required, or
complete the request on a CPU which we just migrated off.
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -685,7 +685,7 @@ void blk_mq_complete_request(struct request *rq)
 		return;
 	}
 
-	cpu = get_cpu();
+	cpu = raw_smp_processor_id();
 	if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags))
 		shared = cpus_share_cache(cpu, ctx->cpu);
 
@@ -697,7 +697,6 @@ void blk_mq_complete_request(struct request *rq)
 	} else {
 		__blk_mq_complete_request(rq);
 	}
-	put_cpu();
 }
 EXPORT_SYMBOL(blk_mq_complete_request);