From:   Nico Pache <npache@redhat.com>
To:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        akpm@linux-foundation.org
Cc:     shakeelb@google.com, ktkhai@virtuozzo.com, shy828301@gmail.com,
        guro@fb.com, vbabka@suse.cz, vdavydov.dev@gmail.com,
        raquini@redhat.com, Rafael Aquini <aquini@redhat.com>
Subject: [RFC PATCH 1/2] include/linux/gfp.h: Do not allocate pages on a offlined node
Date:   Sun,  5 Dec 2021 22:33:37 -0500
Message-Id: <20211206033338.743270-2-npache@redhat.com>
In-Reply-To: <20211206033338.743270-1-npache@redhat.com>
References: <20211206033338.743270-1-npache@redhat.com>
MIME-Version: 1.0
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We shouldn't allocate pages on a unavailable node. Add a check for this
in __alloc_pages_node and return NULL to avoid issues further down the
callchain.

Also update the VM_WARN_ON in __alloc_pages_node which could skip this
warn if the gfp_mask is not GFP_THISNODE.

Co-developed-by: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Nico Pache <npache@redhat.com>
---
 include/linux/gfp.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index b976c4177299..e7e18f6d0d9d 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -565,7 +565,10 @@ static inline struct page *
 __alloc_pages_node(int nid, gfp_t gfp_mask, unsigned int order)
 {
 	VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
-	VM_WARN_ON((gfp_mask & __GFP_THISNODE) && !node_online(nid));
+	VM_WARN_ON(!node_online(nid));
+
+	if (!node_online(nid))
+		return NULL;
 
 	return __alloc_pages(gfp_mask, order, nid, NULL);
 }
-- 
2.33.1