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From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Subject: [Intel-gfx] [CI 4/4] drm/i915: convert get_user_pages() --> pin_user_pages()
Date: Fri, 22 May 2020 18:42:09 +0100
Message-ID: <20200522174209.8885-4-chris@chris-wilson.co.uk> (raw)
In-Reply-To: <20200522174209.8885-1-chris@chris-wilson.co.uk>

From: John Hubbard <jhubbard@nvidia.com>

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>
---
 drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 22 ++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 8b0708708671..4d3c0c2fdbb0 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -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
@@ -598,11 +599,14 @@ static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 				      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(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);
@@ -675,7 +679,7 @@ 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;
 
-- 
2.20.1

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  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-22 17:42 [Intel-gfx] [CI 1/4] mm/gup: move __get_user_pages_fast() down a few lines in gup.c Chris Wilson
2020-05-22 17:42 ` [Intel-gfx] [CI 2/4] mm/gup: refactor and de-duplicate gup_fast() code Chris Wilson
2020-05-22 17:42 ` [Intel-gfx] [CI 3/4] mm/gup: introduce pin_user_pages_fast_only() Chris Wilson
2020-05-22 17:42 ` Chris Wilson [this message]
2020-05-22 18:08 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [CI,1/4] mm/gup: move __get_user_pages_fast() down a few lines in gup.c Patchwork
2020-05-22 18:10 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2020-05-22 18:29 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork
2020-05-22 19:00 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [CI,1/4] mm/gup: move __get_user_pages_fast() down a few lines in gup.c (rev2) Patchwork
2020-05-22 19:02 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2020-05-22 19:20 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2020-05-23  6:14 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork

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