Commit 02712bc3 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jason Gunthorpe
Browse files

mm/hmm: move hmm_vma_range_done and hmm_vma_fault to nouveau 

These two functions are marked as a legacy APIs to get rid of, but seem to
suit the current nouveau flow.  Move it to the only user in preparation
for fixing a locking bug involving caller and callee.  All comments
referring to the old API have been removed as this now is a driver private
helper.

Link: https://lore.kernel.org/r/20190724065258.16603-3-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 2bcbeaef

drivers/gpu/drm/nouveau/nouveau_svm.c

+44 −2
Original line number Diff line number Diff line
@@ -475,6 +475,48 @@ nouveau_svm_fault_cache(struct nouveau_svm *svm, 
		fault->inst, fault->addr, fault->access);

}



static inline bool

nouveau_range_done(struct hmm_range *range)

{

	bool ret = hmm_range_valid(range);



	hmm_range_unregister(range);

	return ret;

}



static int

nouveau_range_fault(struct hmm_mirror *mirror, struct hmm_range *range,

		    bool block)

{

	long ret;



	range->default_flags = 0;

	range->pfn_flags_mask = -1UL;



	ret = hmm_range_register(range, mirror,

				 range->start, range->end,

				 PAGE_SHIFT);

	if (ret)

		return (int)ret;



	if (!hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT)) {

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

		return -EAGAIN;

	}



	ret = hmm_range_fault(range, block);

	if (ret <= 0) {

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

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

			ret = -EBUSY;

		} else if (ret == -EAGAIN)

			ret = -EBUSY;

		hmm_range_unregister(range);

		return ret;

	}

	return 0;

}



static int

nouveau_svm_fault(struct nvif_notify *notify)

{
@@ -649,10 +691,10 @@ nouveau_svm_fault(struct nvif_notify *notify) 
		range.values = nouveau_svm_pfn_values;

		range.pfn_shift = NVIF_VMM_PFNMAP_V0_ADDR_SHIFT;

again:

		ret = hmm_vma_fault(&svmm->mirror, &range, true);

		ret = nouveau_range_fault(&svmm->mirror, &range, true);

		if (ret == 0) {

			mutex_lock(&svmm->mutex);

			if (!hmm_vma_range_done(&range)) {

			if (!nouveau_range_done(&range)) {

				mutex_unlock(&svmm->mutex);

				goto again;

			}

include/linux/hmm.h

+0 −54
Original line number Diff line number Diff line
@@ -484,60 +484,6 @@ long hmm_range_dma_unmap(struct hmm_range *range, 
 */

#define HMM_RANGE_DEFAULT_TIMEOUT 1000



/* This is a temporary helper to avoid merge conflict between trees. */

static inline bool hmm_vma_range_done(struct hmm_range *range)

{

	bool ret = hmm_range_valid(range);



	hmm_range_unregister(range);

	return ret;

}



/* This is a temporary helper to avoid merge conflict between trees. */

static inline int hmm_vma_fault(struct hmm_mirror *mirror,

				struct hmm_range *range, bool block)

{

	long ret;



	/*

	 * With the old API the driver must set each individual entries with

	 * the requested flags (valid, write, ...). So here we set the mask to

	 * keep intact the entries provided by the driver and zero out the

	 * default_flags.

	 */

	range->default_flags = 0;

	range->pfn_flags_mask = -1UL;



	ret = hmm_range_register(range, mirror,

				 range->start, range->end,

				 PAGE_SHIFT);

	if (ret)

		return (int)ret;



	if (!hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT)) {

		/*

		 * The mmap_sem was taken by driver we release it here and

		 * returns -EAGAIN which correspond to mmap_sem have been

		 * drop in the old API.

		 */

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

		return -EAGAIN;

	}



	ret = hmm_range_fault(range, block);

	if (ret <= 0) {

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

			/* Same as above, drop mmap_sem to match old API. */

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

			ret = -EBUSY;

		} else if (ret == -EAGAIN)

			ret = -EBUSY;

		hmm_range_unregister(range);

		return ret;

	}

	return 0;

}



/* Below are for HMM internal use only! Not to be used by device driver! */

static inline void hmm_mm_init(struct mm_struct *mm)

{