linux-kernel - [PATCH 2] mm/kvmalloc: do not call kmalloc for size > KMALLOC_MAX

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Date:   Thu, 01 Nov 2018 13:09:16 +0300
From:   Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To:     linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 2] mm/kvmalloc: do not call kmalloc for size >
 KMALLOC_MAX_SIZE

Allocations over KMALLOC_MAX_SIZE could be served only by vmalloc.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
---
 mm/util.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/util.c b/mm/util.c
index 8bf08b5b5760..f5f04fa22814 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -392,6 +392,9 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node)
 	gfp_t kmalloc_flags = flags;
 	void *ret;
 
+	if (size > KMALLOC_MAX_SIZE)
+		goto fallback;
+
 	/*
 	 * vmalloc uses GFP_KERNEL for some internal allocations (e.g page tables)
 	 * so the given set of flags has to be compatible.
@@ -422,6 +425,7 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node)
 	if (ret || size <= PAGE_SIZE)
 		return ret;
 
+fallback:
 	return __vmalloc_node_flags_caller(size, node, flags,
 			__builtin_return_address(0));
 }