[PATCH 2/2] drm/ttm: swap consecutive allocated pooled pages v3

[He, Roger]

Series is:
Reviewed-by: Roger He <Hongbo.He at amd.com>

Thanks
Roger(Hongbo.He)
-----Original Message-----
From: Christian König [mailto:ckoenig.leichtzumerken at gmail.com] 
Sent: Monday, December 04, 2017 8:46 PM
To: dri-devel at lists.freedesktop.org; amd-gfx at lists.freedesktop.org; He, Roger <Hongbo.He at amd.com>
Subject: [PATCH 2/2] drm/ttm: swap consecutive allocated pooled pages v3

When we detect consecutive allocation of pages swap them to avoid accidentally freeing them as huge page.

v2: use swap
v3: check if it's really the first allocated page

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/ttm/ttm_page_alloc.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
index 7c4d4edce0ba..da8a50f7c8fe 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -954,8 +954,13 @@ static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
 	r = ttm_page_pool_get_pages(pool, &plist, flags, cstate,
 				    npages - count, 0);
 
-	list_for_each_entry(p, &plist, lru)
+	first = count;
+	list_for_each_entry(p, &plist, lru) {
+		/* Swap the pages if we detect consecutive order */
+		if (count > first && pages[count - 1] == p - 1)
+			swap(p, pages[count - 1]);
 		pages[count++] = p;
+	}
 
 	if (r) {
 		/* If there is any pages in the list put them back to
--
2.11.0