mm/page_alloc: correct return value when failing at preparing

mainline inclusion
from mainline-5.14-rc2
commit e5c15cea
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I3ZVL2
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e5c15cea339115edf99dc92282865f173cf84510

-------------------------------------------------

If the array passed in is already partially populated, we should return
"nr_populated" even failing at preparing arguments stage.

Link: https://lkml.kernel.org/r/20210713152100.10381-3-mgorman@techsingularity.netSigned-off-by: NYanfei Xu <yanfei.xu@windriver.com>
Signed-off-by: NMel Gorman <mgorman@techsingularity.net>
Link: https://lore.kernel.org/r/20210709102855.55058-1-yanfei.xu@windriver.comSigned-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit e5c15cea)
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>
Reviewed-by: Ntong tiangen <tongtiangen@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mm/page_alloc.c

@@ -4987,7 +4987,7 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
 	gfp &= gfp_allowed_mask;
 	alloc_gfp = gfp;
 	if (!prepare_alloc_pages(gfp, 0, preferred_nid, nodemask, &ac, &alloc_gfp, &alloc_flags))
-		return 0;
+		return nr_populated;
 	gfp = alloc_gfp;
 
 	/* Find an allowed local zone that meets the low watermark. */