Am 28.07.20 um 15:58 schrieb Daniel Vetter:
GPU drivers need this in their shrinkers, to be able to throw out mmap'ed buffers. Note that we also need dma_resv_lock in shrinkers, but that loop is resolved by trylocking in shrinkers.
So full hierarchy is now (ignore some of the other branches we already have primed):
mmap_read_lock -> dma_resv -> shrinkers -> i_mmap_lock_write
I hope that's not inconsistent with anything mm or fs does, adding relevant people.
Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: Sumit Semwal sumit.semwal@linaro.org Cc: "Christian König" christian.koenig@amd.com Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Cc: Dave Chinner david@fromorbit.com Cc: Qian Cai cai@lca.pw Cc: linux-xfs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: Thomas Hellström (Intel) thomas_os@shipmail.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Jason Gunthorpe jgg@mellanox.com Cc: linux-mm@kvack.org Cc: linux-rdma@vger.kernel.org Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com
Reviewed-by: Christian König christian.koenig@amd.com
drivers/dma-buf/dma-resv.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 0e6675ec1d11..9678162a4ac5 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -104,12 +104,14 @@ static int __init dma_resv_lockdep(void) struct mm_struct *mm = mm_alloc(); struct ww_acquire_ctx ctx; struct dma_resv obj;
- struct address_space mapping; int ret;
if (!mm) return -ENOMEM; dma_resv_init(&obj);
- address_space_init_once(&mapping);
mmap_read_lock(mm); ww_acquire_init(&ctx, &reservation_ww_class); @@ -117,6 +119,9 @@ static int __init dma_resv_lockdep(void) if (ret == -EDEADLK) dma_resv_lock_slow(&obj, &ctx); fs_reclaim_acquire(GFP_KERNEL);
- /* for unmap_mapping_range on trylocked buffer objects in shrinkers */
- i_mmap_lock_write(&mapping);
- i_mmap_unlock_write(&mapping); #ifdef CONFIG_MMU_NOTIFIER lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); __dma_fence_might_wait();