From be957c886d92aa9caf0f63aee2c77d1497217d93 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Fri, 1 May 2020 15:20:45 -0300 Subject: mm/hmm: make hmm_range_fault return 0 or -1 hmm_vma_walk->last is supposed to be updated after every write to the pfns, so that it can be returned by hmm_range_fault(). However, this is not done consistently. Fortunately nothing checks the return code of hmm_range_fault() for anything other than error. More importantly last must be set before returning -EBUSY as it is used to prevent reading an output pfn as an input flags when the loop restarts. For clarity and simplicity make hmm_range_fault() return 0 or -ERRNO. Only set last when returning -EBUSY. Link: https://lore.kernel.org/r/2-v2-b4e84f444c7d+24f57-hmm_no_flags_jgg@mellanox.com Acked-by: Felix Kuehling Tested-by: Ralph Campbell Reviewed-by: Christoph Hellwig Signed-off-by: Jason Gunthorpe --- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/amd') diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 6309ff72bd78..7eb745b8acce 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -852,12 +852,12 @@ retry: down_read(&mm->mmap_sem); r = hmm_range_fault(range); up_read(&mm->mmap_sem); - if (unlikely(r <= 0)) { + if (unlikely(r)) { /* * FIXME: This timeout should encompass the retry from * mmu_interval_read_retry() as well. */ - if ((r == 0 || r == -EBUSY) && !time_after(jiffies, timeout)) + if (r == -EBUSY && !time_after(jiffies, timeout)) goto retry; goto out_free_pfns; } -- cgit v1.2.3