From 9557feee39b75ceb502b4777e08706df1ddf10ed Mon Sep 17 00:00:00 2001
From: Dave Jiang <dave.jiang@intel.com>
Date: Fri, 24 Feb 2017 14:57:05 -0800
Subject: [PATCH] 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: Dave 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/dax/dax.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index 922ec461dcaa3..b90bb301bda0b 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -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;
}
--
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