linux-kernel - [PATCH] drm/xe: avoid plain 64-bit division

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Message-Id: <20250324210612.2927194-1-arnd@kernel.org>
Date: Mon, 24 Mar 2025 22:06:02 +0100
From: Arnd Bergmann <arnd@...nel.org>
To: Lucas De Marchi <lucas.demarchi@...el.com>,
	Thomas Hellström <thomas.hellstrom@...ux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@...el.com>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Oak Zeng <oak.zeng@...el.com>,
	Matthew Brost <matthew.brost@...el.com>
Cc: Arnd Bergmann <arnd@...db.de>,
	Matthew Auld <matthew.auld@...el.com>,
	Nirmoy Das <nirmoy.das@...el.com>,
	Akshata Jahagirdar <akshata.jahagirdar@...el.com>,
	José Roberto de Souza <jose.souza@...el.com>,
	intel-xe@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] drm/xe: avoid plain 64-bit division

From: Arnd Bergmann <arnd@...db.de>

Building the xe driver for i386 results in a link time warning:

x86_64-linux-ld: drivers/gpu/drm/xe/xe_migrate.o: in function `xe_migrate_vram':
xe_migrate.c:(.text+0x1e15): undefined reference to `__udivdi3'

Avoid this by using DIV_U64_ROUND_UP() instead of DIV_ROUND_UP().  The driver
is unlikely to be used on 32=bit hardware, so the extra cost here is not
too important.

Fixes: 9c44fd5f6e8a ("drm/xe: Add migrate layer functions for SVM support")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/gpu/drm/xe/xe_migrate.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
index df4282c71bf0..aafb6209f2d0 100644
--- a/drivers/gpu/drm/xe/xe_migrate.c
+++ b/drivers/gpu/drm/xe/xe_migrate.c
@@ -1547,7 +1547,7 @@ void xe_migrate_wait(struct xe_migrate *m)
 static u32 pte_update_cmd_size(u64 size)
 {
 	u32 num_dword;
-	u64 entries = DIV_ROUND_UP(size, XE_PAGE_SIZE);
+	u64 entries = DIV_U64_ROUND_UP(size, XE_PAGE_SIZE);
 
 	XE_WARN_ON(size > MAX_PREEMPTDISABLE_TRANSFER);
 	/*
@@ -1558,7 +1558,7 @@ static u32 pte_update_cmd_size(u64 size)
 	 * 2 dword for the page table's physical location
 	 * 2*n dword for value of pte to fill (each pte entry is 2 dwords)
 	 */
-	num_dword = (1 + 2) * DIV_ROUND_UP(entries, 0x1ff);
+	num_dword = (1 + 2) * DIV_U64_ROUND_UP(entries, 0x1ff);
 	num_dword += entries * 2;
 
 	return num_dword;
-- 
2.39.5