Am Montag, den 25.05.2020, 16:49 -0700 schrieb John Hubbard:

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

Thanks, I've applied this to etnaviv/next.

Regards, Lucas

---

Hi,

Changes since v1:

• Rebased onto Linux 5.7-rc7

• Added: Lucas Stach

thanks John Hubbard NVIDIA

drivers/gpu/drm/etnaviv/etnaviv_gem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c index dc9ef302f517..0f4578dc169d 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c @@ -675,10 +675,10 @@ static int etnaviv_gem_userptr_get_pages(struct etnaviv_gem_object *etnaviv_obj) uint64_t ptr = userptr->ptr + pinned * PAGE_SIZE; struct page **pages = pvec + pinned;

• ret = get_user_pages_fast(ptr, num_pages,
  

• ret = pin_user_pages_fast(ptr, num_pages,
  		  !userptr->ro ? FOLL_WRITE : 0, pages);
  

  if (ret < 0) {

• 	release_pages(pvec, pinned);
  

• 	unpin_user_pages(pvec, pinned);
  kvfree(pvec);
  return ret;
  

  }

@@ -702,7 +702,7 @@ static void etnaviv_gem_userptr_release(struct etnaviv_gem_object *etnaviv_obj) if (etnaviv_obj->pages) { int npages = etnaviv_obj->base.size >> PAGE_SHIFT;

• release_pages(etnaviv_obj->pages, npages);
  

• unpin_user_pages(etnaviv_obj->pages, npages);
  

  kvfree(etnaviv_obj->pages); }

}