On 2020-05-26 14:00, Souptick Joarder wrote:
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() + release_pages() 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: Souptick Joarder <jrdr.linux@xxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Hi,
I'm compile tested this, but unable to run-time test, so any testing
help is much appriciated.
---
drivers/gpu/drm/radeon/radeon_ttm.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 5d50c9e..e927de2 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -506,7 +506,7 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm)
uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;
struct page **pages = ttm->pages + pinned;
- r = get_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0,
+ r = pin_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0,
pages, NULL);
if (r < 0)
goto release_pages;
@@ -535,7 +535,7 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm)
kfree(ttm->sg);
release_pages:
- release_pages(ttm->pages, pinned);
+ unpin_user_pages(ttm->pages, pinned);
return r;
}
@@ -562,7 +562,7 @@ static void radeon_ttm_tt_unpin_userptr(struct ttm_tt *ttm)
set_page_dirty(page);
Maybe we also need a preceding patch, to fix the above? It should be
set_page_dirty_lock(), rather than set_page_dirty(), unless I'm overlooking
something (which is very possible!).
Either way, from a tunnel vision perspective of changing gup to pup, this
looks good to me, so
Acked-by: John Hubbard <jhubbard@xxxxxxxxxx>
thanks,
--
John Hubbard
NVIDIA
mark_page_accessed(page);
- put_page(page);
+ unpin_user_page(page);
}
sg_free_table(ttm->sg);
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