The patch titled
Subject: drm/i915: convert get_user_pages() --> pin_user_pages()
has been added to the -mm tree. Its filename is
drm-i915-convert-get_user_pages-pin_user_pages.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/drm-i915-convert-get_user_pages-pin_user_pages.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/drm-i915-convert-get_user_pages-pin_user_pages.patch
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------------------------------------------------------
From: John Hubbard <jhubbard@xxxxxxxxxx>
Subject: drm/i915: convert get_user_pages() --> pin_user_pages()
This code was using get_user_pages*(), in a "Case 2" scenario (DMA/RDMA),
using the categorization from [1]. That means that it's time to convert
the get_user_pages*() + put_page() calls to pin_user_pages*() +
unpin_user_pages() calls.
There is some helpful background in [2]: basically, this is a small part
of fixing a long-standing disconnect between pinning pages, and file
systems' use of those pages.
[1] Documentation/core-api/pin_user_pages.rst
[2] "Explicit pinning of user-space pages":
https://lwn.net/Articles/807108/
Link: http://lkml.kernel.org/r/20200519002124.2025955-5-jhubbard@xxxxxxxxxx
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Souptick Joarder <jrdr.linux@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: "Joonas Lahtinen" <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 22 ++++++++++--------
1 file changed, 13 insertions(+), 9 deletions(-)
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c~drm-i915-convert-get_user_pages-pin_user_pages
+++ a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -471,7 +471,7 @@ __i915_gem_userptr_get_pages_worker(stru
down_read(&mm->mmap_sem);
locked = 1;
}
- ret = get_user_pages_remote
+ ret = pin_user_pages_remote
(work->task, mm,
obj->userptr.ptr + pinned * PAGE_SIZE,
npages - pinned,
@@ -507,7 +507,7 @@ __i915_gem_userptr_get_pages_worker(stru
}
mutex_unlock(&obj->mm.lock);
- release_pages(pvec, pinned);
+ unpin_user_pages(pvec, pinned);
kvfree(pvec);
i915_gem_object_put(obj);
@@ -564,6 +564,7 @@ static int i915_gem_userptr_get_pages(st
struct sg_table *pages;
bool active;
int pinned;
+ unsigned int gup_flags = 0;
/* If userspace should engineer that these pages are replaced in
* the vma between us binding this page into the GTT and completion
@@ -598,11 +599,14 @@ static int i915_gem_userptr_get_pages(st
GFP_KERNEL |
__GFP_NORETRY |
__GFP_NOWARN);
- if (pvec) /* defer to worker if malloc fails */
- pinned = __get_user_pages_fast(obj->userptr.ptr,
- num_pages,
- !i915_gem_object_is_readonly(obj),
- pvec);
+ /* defer to worker if malloc fails */
+ if (pvec) {
+ if (!i915_gem_object_is_readonly(obj))
+ gup_flags |= FOLL_WRITE;
+ pinned = pin_user_pages_fast_only(obj->userptr.ptr,
+ num_pages, gup_flags,
+ pvec);
+ }
}
active = false;
@@ -620,7 +624,7 @@ static int i915_gem_userptr_get_pages(st
__i915_gem_userptr_set_active(obj, true);
if (IS_ERR(pages))
- release_pages(pvec, pinned);
+ unpin_user_pages(pvec, pinned);
kvfree(pvec);
return PTR_ERR_OR_ZERO(pages);
@@ -675,7 +679,7 @@ i915_gem_userptr_put_pages(struct drm_i9
}
mark_page_accessed(page);
- put_page(page);
+ unpin_user_page(page);
}
obj->mm.dirty = false;
_
Patches currently in -mm which might be from jhubbard@xxxxxxxxxx are
rapidio-fix-an-error-in-get_user_pages_fast-error-handling.patch
selftests-vm-gitignore-add-mremap_dontunmap.patch
selftests-vm-write_to_hugetlbfsc-fix-unused-variable-warning.patch
mm-gup-introduce-pin_user_pages_unlocked.patch
ivtv-convert-get_user_pages-pin_user_pages.patch
mm-gup-move-__get_user_pages_fast-down-a-few-lines-in-gupc.patch
mm-gup-refactor-and-de-duplicate-gup_fast-code.patch
mm-gup-introduce-pin_user_pages_fast_only.patch
drm-i915-convert-get_user_pages-pin_user_pages.patch
khugepaged-add-self-test-fix-3.patch
rapidio-convert-get_user_pages-pin_user_pages.patch
