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@gmail.com Cc: John Hubbard jhubbard@nvidia.com
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);@@ -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@nvidia.com
thanks,