tools/vm/page_owner_sort.c: avoid repeated judgments

I noticed a detail that needs to be adjusted.  When judging whether a page
is allocated by vmalloc, the value of the variable "tmp" was repeatedly
judged, so the code was adjusted.

This work is coauthored by Yinan Zhang, Jiajian Ye, Shenghong Han, Chongxi
Zhao, Yuhong Feng and Yongqiang Liu.

Link: https://lkml.kernel.org/r/20220414042744.13896-1-caoyixuan2019@email.szu.edu.cnSigned-off-by: Yixuan Cao <caoyixuan2019@email.szu.edu.cn>
Cc: Chongxi Zhao <zhaochongxi2019@email.szu.edu.cn>
Cc: Haowen Bai <baihaowen@meizu.com>
Cc: Jiajian Ye <yejiajian2018@email.szu.edu.cn>
Cc: Sean Anderson <seanga2@gmail.com>
Cc: Shenghong Han <hanshenghong2019@email.szu.edu.cn>
Cc: Yinan Zhang <zhangyinan2019@email.szu.edu.cn>
Cc: Yongqiang Liu <liuyongqiang13@huawei.com>
Cc: Yuhong Feng <yuhongf@szu.edu.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/vm/page_owner_sort.c

@@ -444,10 +444,8 @@ static int get_allocator(const char *buf, const char *migrate_info)
 			tmp--;
 		first_line = ++tmp;
 		tmp = strstr(tmp, "alloc_pages");
-		if (tmp) {
-			if (tmp && first_line <= tmp && tmp < second_line)
-				allocator |= ALLOCATOR_VMALLOC;
-		}
+		if (tmp && first_line <= tmp && tmp < second_line)
+			allocator |= ALLOCATOR_VMALLOC;
 	}
 	if (allocator == 0)
 		allocator = ALLOCATOR_OTHERS;