Commit de4ee728 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jason Gunthorpe
Browse files

nouveau: unlock mmap_sem on all errors from nouveau_range_fault 

Currently nouveau_svm_fault expects nouveau_range_fault to never unlock
mmap_sem, but the latter unlocks it for a random selection of error
codes. Fix this up by always unlocking mmap_sem for non-zero return values
in nouveau_range_fault, and only unlocking it in the caller for successful
returns.

Link: https://lore.kernel.org/r/20190724065258.16603-5-hch@lst.de


Tested-by: default avatarRalph Campbell <rcampbell@nvidia.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent 5fbcf501

drivers/gpu/drm/nouveau/nouveau_svm.c

+6 −5
Original line number Diff line number Diff line
@@ -495,8 +495,10 @@ nouveau_range_fault(struct hmm_mirror *mirror, struct hmm_range *range) 
	ret = hmm_range_register(range, mirror,

				 range->start, range->end,

				 PAGE_SHIFT);

	if (ret)

	if (ret) {

		up_read(&range->vma->vm_mm->mmap_sem);

		return (int)ret;

	}



	if (!hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT)) {

		up_read(&range->vma->vm_mm->mmap_sem);
@@ -505,10 +507,9 @@ nouveau_range_fault(struct hmm_mirror *mirror, struct hmm_range *range) 


	ret = hmm_range_fault(range, true);

	if (ret <= 0) {

		if (ret == -EBUSY || !ret) {

			up_read(&range->vma->vm_mm->mmap_sem);

		if (ret == 0)

			ret = -EBUSY;

		}

		up_read(&range->vma->vm_mm->mmap_sem);

		hmm_range_unregister(range);

		return ret;

	}
@@ -706,8 +707,8 @@ nouveau_svm_fault(struct nvif_notify *notify) 
						NULL);

			svmm->vmm->vmm.object.client->super = false;

			mutex_unlock(&svmm->mutex);

		}

			up_read(&svmm->mm->mmap_sem);

		}



		/* Cancel any faults in the window whose pages didn't manage

		 * to keep their valid bit, or stay writeable when required.