diff options
| author | David Hildenbrand <david@redhat.com> | 2022-11-16 13:26:53 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-12-01 02:58:59 +0300 |
| commit | 7d96eb6a9164607df09c9589ed3ba9ef4e9cc2a6 (patch) | |
| tree | 1ec0ccb47f1cf09d947ab81bc342c0b9e2068d01 | |
| parent | 3298de2c66e0276abe6b95041fd3605a377523fc (diff) | |
| download | linux-7d96eb6a9164607df09c9589ed3ba9ef4e9cc2a6.tar.xz | |
drm/etnaviv: remove FOLL_FORCE usage
GUP now supports reliable R/O long-term pinning in COW mappings, such
that we break COW early. MAP_SHARED VMAs only use the shared zeropage so
far in one corner case (DAXFS file with holes), which can be ignored
because GUP does not support long-term pinning in fsdax (see
check_vma_flags()).
commit cd5297b0855f ("drm/etnaviv: Use FOLL_FORCE for userptr")
documents that FOLL_FORCE | FOLL_WRITE was really only used for reliable
R/O pinning.
Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required
for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop
using FOLL_FORCE, which is really only for ptrace access.
Link: https://lkml.kernel.org/r/20221116102659.70287-15-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Russell King <linux+etnaviv@armlinux.org.uk>
Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
Cc: David Airlie <airlied@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | drivers/gpu/drm/etnaviv/etnaviv_gem.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c index cc386f8a7116..efe2240945d0 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c @@ -638,6 +638,7 @@ static int etnaviv_gem_userptr_get_pages(struct etnaviv_gem_object *etnaviv_obj) struct page **pvec = NULL; struct etnaviv_gem_userptr *userptr = &etnaviv_obj->userptr; int ret, pinned = 0, npages = etnaviv_obj->base.size >> PAGE_SHIFT; + unsigned int gup_flags = FOLL_LONGTERM; might_lock_read(¤t->mm->mmap_lock); @@ -648,14 +649,15 @@ static int etnaviv_gem_userptr_get_pages(struct etnaviv_gem_object *etnaviv_obj) if (!pvec) return -ENOMEM; + if (!userptr->ro) + gup_flags |= FOLL_WRITE; + do { unsigned num_pages = npages - pinned; uint64_t ptr = userptr->ptr + pinned * PAGE_SIZE; struct page **pages = pvec + pinned; - ret = pin_user_pages_fast(ptr, num_pages, - FOLL_WRITE | FOLL_FORCE | FOLL_LONGTERM, - pages); + ret = pin_user_pages_fast(ptr, num_pages, gup_flags, pages); if (ret < 0) { unpin_user_pages(pvec, pinned); kvfree(pvec); |