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Commit 9557feee authored by Dave Jiang's avatar Dave Jiang Committed by Linus Torvalds
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dax: support for transparent PUD pages for device DAX 

Add transparent huge PUD pages support for device DAX by adding a
pud_fault handler.

Link: http://lkml.kernel.org/r/148545060002.17912.6765687780007547551.stgit@djiang5-desk3.ch.intel.com


Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Nilesh Choudhury <nilesh.choudhury@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a00cc7d9

drivers/dax/dax.c

+48 −0
Original line number Diff line number Diff line
@@ -493,6 +493,51 @@ static int __dax_dev_pmd_fault(struct dax_dev *dax_dev, struct vm_fault *vmf) 
			vmf->flags & FAULT_FLAG_WRITE);

}



#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD

static int __dax_dev_pud_fault(struct dax_dev *dax_dev, struct vm_fault *vmf)

{

	unsigned long pud_addr = vmf->address & PUD_MASK;

	struct device *dev = &dax_dev->dev;

	struct dax_region *dax_region;

	phys_addr_t phys;

	pgoff_t pgoff;

	pfn_t pfn;



	if (check_vma(dax_dev, vmf->vma, __func__))

		return VM_FAULT_SIGBUS;



	dax_region = dax_dev->region;

	if (dax_region->align > PUD_SIZE) {

		dev_dbg(dev, "%s: alignment > fault size\n", __func__);

		return VM_FAULT_SIGBUS;

	}



	/* dax pud mappings require pfn_t_devmap() */

	if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {

		dev_dbg(dev, "%s: alignment > fault size\n", __func__);

		return VM_FAULT_SIGBUS;

	}



	pgoff = linear_page_index(vmf->vma, pud_addr);

	phys = pgoff_to_phys(dax_dev, pgoff, PUD_SIZE);

	if (phys == -1) {

		dev_dbg(dev, "%s: phys_to_pgoff(%#lx) failed\n", __func__,

				pgoff);

		return VM_FAULT_SIGBUS;

	}



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



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

			vmf->flags & FAULT_FLAG_WRITE);

}

#else

static int __dax_dev_pud_fault(struct dax_dev *dax_dev, struct vm_fault *vmf)

{

	return VM_FAULT_FALLBACK;

}

#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */



static int dax_dev_fault(struct vm_fault *vmf)

{

	int rc;
@@ -512,6 +557,9 @@ static int dax_dev_fault(struct vm_fault *vmf) 
	case FAULT_FLAG_SIZE_PMD:

		rc = __dax_dev_pmd_fault(dax_dev, vmf);

		break;

	case FAULT_FLAG_SIZE_PUD:

		rc = __dax_dev_pud_fault(dax_dev, vmf);

		break;

	default:

		return VM_FAULT_FALLBACK;

	}