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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/

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
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: Daniel Vetter <daniel@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Link: http://lkml.kernel.org/r/20200519002124.2025955-5-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
John Hubbard 2020-06-03 15:56:37 -07:00 committed by Linus Torvalds
parent 104acc3276
commit 2170ecfa76
1 changed files with 13 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/gpu/drm/i915/gem/i915_gem_userptr.c
View File

@ -471,7 +471,7 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
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(struct work_struct *_work)
}
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(struct drm_i915_gem_object *obj)
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
@ -606,11 +607,14 @@ static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
*
* We may or may not care.
*/
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);
if (pvec) {
/* defer to worker if malloc fails */
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;
@ -628,7 +632,7 @@ 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);
unpin_user_pages(pvec, pinned);
kvfree(pvec);
return PTR_ERR_OR_ZERO(pages);
@ -683,7 +687,7 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
}
mark_page_accessed(page);
put_page(page);
unpin_user_page(page);
}
obj->mm.dirty = false;