From 5784c7c36eca5a0c9ed662dfd9248de4c90862cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michael=20Niew=C3=B6hner?=
 <c0d3z3r0@users.noreply.github.com>
Date: Wed, 17 Jul 2019 18:09:22 +0200
Subject: [PATCH] Add missing __GFP_HIGHMEM flag to vmalloc
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Make use of __GFP_HIGHMEM flag in vmem_alloc, which is required for
some 32-bit systems to make use of full available memory.
While kernel versions >=4.12-rc1 add this flag implicitly, older
kernels do not.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #9031
---
 module/spl/spl-kmem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c
index 1fdb61e6fc..824b5e89f5 100644
--- a/module/spl/spl-kmem.c
+++ b/module/spl/spl-kmem.c
@@ -180,7 +180,8 @@ spl_kmem_alloc_impl(size_t size, int flags, int node)
 		 */
 		if ((size > spl_kmem_alloc_max) || use_vmem) {
 			if (flags & KM_VMEM) {
-				ptr = __vmalloc(size, lflags, PAGE_KERNEL);
+				ptr = __vmalloc(size, lflags | __GFP_HIGHMEM,
+				    PAGE_KERNEL);
 			} else {
 				return (NULL);
 			}