[PATCH] mm/hmm: fix unused variable warnings

From: Arnd Bergmann <arnd@arndb.de>
To: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ralph Campbell <rcampbell@nvidia.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	John Hubbard <jhubbard@nvidia.com>,
	Dan Williams <dan.j.williams@intel.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH] mm/hmm: fix unused variable warnings
Date: Mon,  4 Mar 2019 21:00:10 +0100	[thread overview]
Message-ID: <20190304200026.1140281-1-arnd@arndb.de> (raw)

When CONFIG_HUGETLB_PAGE is disabled, the only use of the variable 'h'
is compiled out, and the compiler thinks it is unnecessary:

mm/hmm.c: In function 'hmm_range_snapshot':
mm/hmm.c:1015:19: error: unused variable 'h' [-Werror=unused-variable]
    struct hstate *h = hstate_vma(vma);

Rephrase the code to avoid the temporary variable instead, so the
compiler stops warning.

Fixes: 5409a90d4212 ("mm/hmm: support hugetlbfs (snapshotting, faulting and DMA mapping)")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 mm/hmm.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/mm/hmm.c b/mm/hmm.c
index 3c9781037918..c4beb1628cad 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -1012,9 +1012,8 @@ long hmm_range_snapshot(struct hmm_range *range)
 			return -EFAULT;
 
 		if (is_vm_hugetlb_page(vma)) {
-			struct hstate *h = hstate_vma(vma);
-
-			if (huge_page_shift(h) != range->page_shift &&
+			if (range->page_shift !=
+				huge_page_shift(hstate_vma(vma)) &&
 			    range->page_shift != PAGE_SHIFT)
 				return -EINVAL;
 		} else {
@@ -1115,9 +1114,8 @@ long hmm_range_fault(struct hmm_range *range, bool block)
 			return -EFAULT;
 
 		if (is_vm_hugetlb_page(vma)) {
-			struct hstate *h = hstate_vma(vma);
-
-			if (huge_page_shift(h) != range->page_shift &&
+			if (range->page_shift !=
+				huge_page_shift(hstate_vma(vma)) &&
 			    range->page_shift != PAGE_SHIFT)
 				return -EINVAL;
 		} else {
-- 
2.20.0

