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

john.hubbard
2019-08-02T02:19:37Z

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@lst.de

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
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