linux-kernel - [PATCH v2 2/3] sgi-gru: Remove CONFIG_HUGETLB

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Date:   Wed, 24 Jul 2019 17:11:15 +0530
From:   Bharath Vedartham <linux.bhar@...il.com>
To:     sivanich@....com, arnd@...db.de, jhubbard@...dia.com
Cc:     ira.weiny@...el.com, jglisse@...hat.com,
        gregkh@...uxfoundation.org, william.kucharski@...cle.com,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Bharath Vedartham <linux.bhar@...il.com>
Subject: [PATCH v2 2/3] sgi-gru: Remove CONFIG_HUGETLB_PAGE ifdef

is_vm_hugetlb_page has checks for whether CONFIG_HUGETLB_PAGE is defined
or not. If CONFIG_HUGETLB_PAGE is not defined is_vm_hugetlb_page will
always return false. There is no need to have an uneccessary
CONFIG_HUGETLB_PAGE check in the code.

Cc: Ira Weiny <ira.weiny@...el.com>
Cc: John Hubbard <jhubbard@...dia.com>
Cc: Jérôme Glisse <jglisse@...hat.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Dimitri Sivanich <sivanich@....com>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: William Kucharski <william.kucharski@...cle.com>
Cc: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org
Reviewed-by: John Hubbard <jhubbard@...dia.com>
Reviewed-by: William Kucharski <william.kucharski@...cle.com>
Reviewed-by: Ira Weiny <ira.weiny@...el.com>
Signed-off-by: Bharath Vedartham <linux.bhar@...il.com>
---
Changes since v2
	- Added an 'unlikely' if statement as suggested by William
	  Kucharski. This is because of the fact that most systems
	  using this driver won't have CONFIG_HUGE_PAGE enabled and we
	  optimize the branch with an unlikely.

Signed-off-by: Bharath Vedartham <linux.bhar@...il.com>
---
 drivers/misc/sgi-gru/grufault.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index 61b3447..bce47af 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -180,11 +180,11 @@ static int non_atomic_pte_lookup(struct vm_area_struct *vma,
 {
 	struct page *page;
 
-#ifdef CONFIG_HUGETLB_PAGE
-	*pageshift = is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT;
-#else
-	*pageshift = PAGE_SHIFT;
-#endif
+	if (unlikely(is_vm_hugetlb_page(vma)))
+		*pageshift = HPAGE_SHIFT;
+	else
+		*pageshift = PAGE_SHIFT;
+
 	if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, NULL) <= 0)
 		return -EFAULT;
 	*paddr = page_to_phys(page);
@@ -238,11 +238,12 @@ static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr,
 		return 1;
 
 	*paddr = pte_pfn(pte) << PAGE_SHIFT;
-#ifdef CONFIG_HUGETLB_PAGE
-	*pageshift = is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT;
-#else
-	*pageshift = PAGE_SHIFT;
-#endif
+
+	if (unlikely(is_vm_hugetlb_page(vma)))
+		*pageshift = HPAGE_SHIFT;
+	else
+		*pageshift = PAGE_SHIFT;
+
 	return 0;
 
 err:
-- 
2.7.4