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nouveau: unlock mmap_sem on all errors from nouveau_range_fault

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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: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Christoph Hellwig 2019-07-24 08:52:55 +02:00 committed by Jason Gunthorpe
parent 5fbcf5015d
commit de4ee72846
1 changed files with 6 additions and 5 deletions
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11
drivers/gpu/drm/nouveau/nouveau_svm.c
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@ -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 @@ again:
NULL);
svmm->vmm->vmm.object.client->super = false;
mutex_unlock(&svmm->mutex);
up_read(&svmm->mm->mmap_sem);
}
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.