From 7dd1b884f777beee4c0f3471a327697005118db8 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Tue, 28 Jul 2020 15:58:39 +0200 Subject: dma-resv: lockdep-prime address_space->i_mmap_rwsem for dma-resv MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. Reviewed-by: Thomas Hellström Reviewed-by: Christian König Signed-off-by: Daniel Vetter Cc: Sumit Semwal Cc: "Christian König" Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Cc: Dave Chinner Cc: Qian Cai Cc: linux-xfs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: Thomas Hellström (Intel) Cc: Andrew Morton Cc: Jason Gunthorpe Cc: linux-mm@kvack.org Cc: linux-rdma@vger.kernel.org Cc: Maarten Lankhorst Link: https://patchwork.freedesktop.org/patch/msgid/20200728135839.1035515-1-daniel.vetter@ffwll.ch --- drivers/dma-buf/dma-resv.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/dma-buf') diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 434a3314fb0e..1c8f2581cb09 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -98,12 +98,14 @@ 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); @@ -111,6 +113,9 @@ 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(); -- cgit v1.2.3