Commit 2232c638 authored by Dan Williams's avatar Dan Williams Committed by Dave Jiang
Browse files

device-dax: Enable page_mapping() 



In support of enabling memory_failure() handling for device-dax
mappings, set the ->mapping association of pages backing device-dax
mappings. The rmap implementation requires page_mapping() to return the
address_space hosting the vmas that map the page.

The ->mapping pointer is never cleared. There is no possibility for the
page to become associated with another address_space while the device is
enabled. When the device is disabled the 'struct page' array for the
device is destroyed / later reinitialized to zero.

Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
parent 226ab561

drivers/dax/device.c

+38 −17
Original line number Diff line number Diff line
@@ -245,12 +245,11 @@ __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff, 
}



static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,

				struct vm_fault *vmf)

				struct vm_fault *vmf, pfn_t *pfn)

{

	struct device *dev = &dev_dax->dev;

	struct dax_region *dax_region;

	phys_addr_t phys;

	pfn_t pfn;

	unsigned int fault_size = PAGE_SIZE;



	if (check_vma(dev_dax, vmf->vma, __func__))
@@ -272,20 +271,19 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax, 
		return VM_FAULT_SIGBUS;

	}



	pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);

	*pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);



	return vmf_insert_mixed(vmf->vma, vmf->address, pfn);

	return vmf_insert_mixed(vmf->vma, vmf->address, *pfn);

}



static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,

				struct vm_fault *vmf)

				struct vm_fault *vmf, pfn_t *pfn)

{

	unsigned long pmd_addr = vmf->address & PMD_MASK;

	struct device *dev = &dev_dax->dev;

	struct dax_region *dax_region;

	phys_addr_t phys;

	pgoff_t pgoff;

	pfn_t pfn;

	unsigned int fault_size = PMD_SIZE;



	if (check_vma(dev_dax, vmf->vma, __func__))
@@ -321,22 +319,21 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, 
		return VM_FAULT_SIGBUS;

	}



	pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);

	*pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);



	return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, pfn,

	return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, *pfn,

			vmf->flags & FAULT_FLAG_WRITE);

}



#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD

static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,

				struct vm_fault *vmf)

				struct vm_fault *vmf, pfn_t *pfn)

{

	unsigned long pud_addr = vmf->address & PUD_MASK;

	struct device *dev = &dev_dax->dev;

	struct dax_region *dax_region;

	phys_addr_t phys;

	pgoff_t pgoff;

	pfn_t pfn;

	unsigned int fault_size = PUD_SIZE;
@@ -373,14 +370,14 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, 
		return VM_FAULT_SIGBUS;

	}



	pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);

	*pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);



	return vmf_insert_pfn_pud(vmf->vma, vmf->address, vmf->pud, pfn,

	return vmf_insert_pfn_pud(vmf->vma, vmf->address, vmf->pud, *pfn,

			vmf->flags & FAULT_FLAG_WRITE);

}

#else

static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,

				struct vm_fault *vmf)

				struct vm_fault *vmf, pfn_t *pfn)

{

	return VM_FAULT_FALLBACK;

}
@@ -389,8 +386,10 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, 
static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,

		enum page_entry_size pe_size)

{

	int rc, id;

	struct file *filp = vmf->vma->vm_file;

	unsigned long fault_size;

	int rc, id;

	pfn_t pfn;

	struct dev_dax *dev_dax = filp->private_data;



	dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
@@ -400,17 +399,39 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, 
	id = dax_read_lock();

	switch (pe_size) {

	case PE_SIZE_PTE:

		rc = __dev_dax_pte_fault(dev_dax, vmf);

		fault_size = PAGE_SIZE;

		rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn);

		break;

	case PE_SIZE_PMD:

		rc = __dev_dax_pmd_fault(dev_dax, vmf);

		fault_size = PMD_SIZE;

		rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn);

		break;

	case PE_SIZE_PUD:

		rc = __dev_dax_pud_fault(dev_dax, vmf);

		fault_size = PUD_SIZE;

		rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn);

		break;

	default:

		rc = VM_FAULT_SIGBUS;

	}



	if (rc == VM_FAULT_NOPAGE) {

		unsigned long i;



		/*

		 * In the device-dax case the only possibility for a

		 * VM_FAULT_NOPAGE result is when device-dax capacity is

		 * mapped. No need to consider the zero page, or racing

		 * conflicting mappings.

		 */

		for (i = 0; i < fault_size / PAGE_SIZE; i++) {

			struct page *page;



			page = pfn_to_page(pfn_t_to_pfn(pfn) + i);

			if (page->mapping)

				continue;

			page->mapping = filp->f_mapping;

		}

	}

	dax_read_unlock(id);



	return rc;

CRA Git | Maintained and supported by SUSTech CRA and CCSE