mm/hmm: make hmm_range_fault return 0 or -1 (be957c88) · Commits · 戴 / test

Documentation/vm/hmm.rst

+1 −1

Original line number	Diff line number	Diff line
		@@ -161,7 +161,7 @@ device must complete the update before the driver callback returns.
		When the device driver wants to populate a range of virtual addresses, it can
		use::

		long hmm_range_fault(struct hmm_range *range);
		int hmm_range_fault(struct hmm_range *range);

		It will trigger a page fault on missing or read-only entries if write access is
		requested (see below). Page faults use the generic mm page fault code path just

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

drivers/gpu/drm/nouveau/nouveau_svm.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -536,7 +536,7 @@ static int nouveau_range_fault(struct nouveau_svmm *svmm,
		.pfn_shift = NVIF_VMM_PFNMAP_V0_ADDR_SHIFT,
		};
		struct mm_struct *mm = notifier->notifier.mm;
		long ret;
		int ret;

		while (true) {
		if (time_after(jiffies, timeout))
		@@ -548,8 +548,8 @@ static int nouveau_range_fault(struct nouveau_svmm *svmm,
		down_read(&mm->mmap_sem);
		ret = hmm_range_fault(&range);
		up_read(&mm->mmap_sem);
		if (ret <= 0) {
		if (ret == 0 \|\| ret == -EBUSY)
		if (ret) {
		if (ret == -EBUSY)
		continue;
		return ret;
		}

include/linux/hmm.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -120,7 +120,7 @@ static inline struct page hmm_device_entry_to_page(const struct hmm_range rang
		/*
		* Please see Documentation/vm/hmm.rst for how to use the range API.
		*/
		long hmm_range_fault(struct hmm_range *range);
		int hmm_range_fault(struct hmm_range *range);

		/*
		* HMM_RANGE_DEFAULT_TIMEOUT - default timeout (ms) when waiting for a range

mm/hmm.c

+9 −16

Original line number	Diff line number	Diff line
		@@ -174,7 +174,6 @@ static int hmm_vma_walk_hole(unsigned long addr, unsigned long end,
		}
		if (required_fault)
		return hmm_vma_fault(addr, end, required_fault, walk);
		hmm_vma_walk->last = addr;
		return hmm_pfns_fill(addr, end, range, HMM_PFN_NONE);
		}

		@@ -207,7 +206,6 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
		pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
		for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++)
		pfns[i] = hmm_device_entry_from_pfn(range, pfn) \| cpu_flags;
		hmm_vma_walk->last = end;
		return 0;
		}
		#else /* CONFIG_TRANSPARENT_HUGEPAGE */
		@@ -386,13 +384,10 @@ again:
		r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, pfns);
		if (r) {
		/* hmm_vma_handle_pte() did pte_unmap() */
		hmm_vma_walk->last = addr;
		return r;
		}
		}
		pte_unmap(ptep - 1);

		hmm_vma_walk->last = addr;
		return 0;
		}

		@@ -455,7 +450,6 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end,
		for (i = 0; i < npages; ++i, ++pfn)
		pfns[i] = hmm_device_entry_from_pfn(range, pfn) \|
		cpu_flags;
		hmm_vma_walk->last = end;
		goto out_unlock;
		}

		@@ -500,7 +494,6 @@ static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask,
		for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
		range->pfns[i] = hmm_device_entry_from_pfn(range, pfn) \|
		cpu_flags;
		hmm_vma_walk->last = end;
		spin_unlock(ptl);
		return 0;
		}
		@@ -537,7 +530,6 @@ static int hmm_vma_walk_test(unsigned long start, unsigned long end,
		return -EFAULT;

		hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
		hmm_vma_walk->last = end;

		/* Skip this vma and continue processing the next vma. */
		return 1;
		@@ -555,9 +547,7 @@ static const struct mm_walk_ops hmm_walk_ops = {
		* hmm_range_fault - try to fault some address in a virtual address range
		* @range: argument structure
		*
		* Return: the number of valid pages in range->pfns[] (from range start
		* address), which may be zero. On error one of the following status codes
		* can be returned:
		* Returns 0 on success or one of the following error codes:
		*
		* -EINVAL: Invalid arguments or mm or virtual address is in an invalid vma
		* (e.g., device file vma).
		@@ -572,7 +562,7 @@ static const struct mm_walk_ops hmm_walk_ops = {
		* This is similar to get_user_pages(), except that it can read the page tables
		* without mutating them (ie causing faults).
		*/
		long hmm_range_fault(struct hmm_range *range)
		int hmm_range_fault(struct hmm_range *range)
		{
		struct hmm_vma_walk hmm_vma_walk = {
		.range = range,
		@@ -590,10 +580,13 @@ long hmm_range_fault(struct hmm_range *range)
		return -EBUSY;
		ret = walk_page_range(mm, hmm_vma_walk.last, range->end,
		&hmm_walk_ops, &hmm_vma_walk);
		/*
		* When -EBUSY is returned the loop restarts with
		* hmm_vma_walk.last set to an address that has not been stored
		* in pfns. All entries < last in the pfn array are set to their
		* output, and all >= are still at their input values.
		*/
		} while (ret == -EBUSY);

		if (ret)
		return ret;
		return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT;
		}
		EXPORT_SYMBOL(hmm_range_fault);

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