dma-mapping: benchmark: handle NUMA_NO_NODE correctly

cpumask_of_node() can be called for NUMA_NO_NODE inside do_map_benchmark()
resulting in the following sanitizer report:

UBSAN: array-index-out-of-bounds in ./arch/x86/include/asm/topology.h:72:28
index -1 is out of range for type 'cpumask [64][1]'
CPU: 1 PID: 990 Comm: dma_map_benchma Not tainted 6.9.0-rc6 #29
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Call Trace:
 <TASK>
dump_stack_lvl (lib/dump_stack.c:117)
ubsan_epilogue (lib/ubsan.c:232)
__ubsan_handle_out_of_bounds (lib/ubsan.c:429)
cpumask_of_node (arch/x86/include/asm/topology.h:72) [inline]
do_map_benchmark (kernel/dma/map_benchmark.c:104)
map_benchmark_ioctl (kernel/dma/map_benchmark.c:246)
full_proxy_unlocked_ioctl (fs/debugfs/file.c:333)
__x64_sys_ioctl (fs/ioctl.c:890)
do_syscall_64 (arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

Use cpumask_of_node() in place when binding a kernel thread to a cpuset
of a particular node.

Note that the provided node id is checked inside map_benchmark_ioctl().
It's just a NUMA_NO_NODE case which is not handled properly later.

Found by Linux Verification Center (linuxtesting.org).

Fixes: 65789da ("dma-mapping: add benchmark support for streaming DMA APIs")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Barry Song <baohua@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

kernel/dma/map_benchmark.c

@@ -101,7 +101,6 @@ static int do_map_benchmark(struct map_benchmark_data *map)
 	struct task_struct **tsk;
 	int threads = map->bparam.threads;
 	int node = map->bparam.node;
-	const cpumask_t *cpu_mask = cpumask_of_node(node);
 	u64 loops;
 	int ret = 0;
 	int i;
@@ -124,7 +123,7 @@ static int do_map_benchmark(struct map_benchmark_data *map)
 		}
 
 		if (node != NUMA_NO_NODE)
-			kthread_bind_mask(tsk[i], cpu_mask);
+			kthread_bind_mask(tsk[i], cpumask_of_node(node));
 	}
 
 	/* clear the old value in the previous benchmark */