[Xen-devel] [PATCH 06/34] drm/i915: convert put_page() to put_user_page*()

[john.hubbard@xxxxxxxxx]

From: John Hubbard <jhubbard@xxxxxxxxxx>

For pages that were retained via get_user_pages*(), release those pages
via the new put_user_page*() routines, instead of via put_page() or
release_pages().

This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
("mm: introduce put_user_page*(), placeholder versions").

Note that this effectively changes the code's behavior in
i915_gem_userptr_put_pages(): it now calls set_page_dirty_lock(),
instead of set_page_dirty(). This is probably more accurate.

As Christophe Hellwig put it, "set_page_dirty() is only safe if we are
dealing with a file backed page where we have reference on the inode it
hangs off." [1]

[1] https://lore.kernel.org/r/20190723153640.GB720@xxxxxx

Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
---
 drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c 
b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 528b61678334..c18008d3cc2a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -527,7 +527,7 @@ __i915_gem_userptr_get_pages_worker(struct work_struct 
*_work)
        }
        mutex_unlock(&obj->mm.lock);
 
-       release_pages(pvec, pinned);
+       put_user_pages(pvec, pinned);
        kvfree(pvec);
 
        i915_gem_object_put(obj);
@@ -640,7 +640,7 @@ static int i915_gem_userptr_get_pages(struct 
drm_i915_gem_object *obj)
                __i915_gem_userptr_set_active(obj, true);
 
        if (IS_ERR(pages))
-               release_pages(pvec, pinned);
+               put_user_pages(pvec, pinned);
        kvfree(pvec);
 
        return PTR_ERR_OR_ZERO(pages);
@@ -663,11 +663,8 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
        i915_gem_gtt_finish_pages(obj, pages);
 
        for_each_sgt_page(page, sgt_iter, pages) {
-               if (obj->mm.dirty)
-                       set_page_dirty(page);
-
                mark_page_accessed(page);
-               put_page(page);
+               put_user_pages_dirty_lock(&page, 1, obj->mm.dirty);
        }
        obj->mm.dirty = false;
 
-- 
2.22.0


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