From: Joao Martins <joao.m.martins@xxxxxxxxxx>
Subject: device-dax: set mapping prior to vmf_insert_pfn{,_pmd,pud}()
Normally, the @page mapping is set prior to inserting the page into a page
table entry. Make device-dax adhere to the same ordering, rather than
setting mapping after the PTE is inserted.
The address_space never changes and it is always associated with the same
inode and underlying pages. So, the page mapping is set once but cleared
when the struct pages are removed/freed (i.e. after
{devm_}memunmap_pages()).
Link: https://lkml.kernel.org/r/20211202204422.26777-10-joao.m.martins@xxxxxxxxxx
Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: Jane Chu <jane.chu@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/dax/device.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
--- a/drivers/dax/device.c~device-dax-set-mapping-prior-to-vmf_insert_pfn_pmdpud
+++ a/drivers/dax/device.c
@@ -121,6 +121,8 @@ static vm_fault_t __dev_dax_pte_fault(st
*pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
+ dax_set_mapping(vmf, *pfn, fault_size);
+
return vmf_insert_mixed(vmf->vma, vmf->address, *pfn);
}
@@ -161,6 +163,8 @@ static vm_fault_t __dev_dax_pmd_fault(st
*pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
+ dax_set_mapping(vmf, *pfn, fault_size);
+
return vmf_insert_pfn_pmd(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE);
}
@@ -203,6 +207,8 @@ static vm_fault_t __dev_dax_pud_fault(st
*pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
+ dax_set_mapping(vmf, *pfn, fault_size);
+
return vmf_insert_pfn_pud(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE);
}
#else
@@ -217,7 +223,6 @@ static vm_fault_t dev_dax_huge_fault(str
enum page_entry_size pe_size)
{
struct file *filp = vmf->vma->vm_file;
- unsigned long fault_size;
vm_fault_t rc = VM_FAULT_SIGBUS;
int id;
pfn_t pfn;
@@ -230,23 +235,18 @@ static vm_fault_t dev_dax_huge_fault(str
id = dax_read_lock();
switch (pe_size) {
case PE_SIZE_PTE:
- fault_size = PAGE_SIZE;
rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn);
break;
case PE_SIZE_PMD:
- fault_size = PMD_SIZE;
rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn);
break;
case PE_SIZE_PUD:
- fault_size = PUD_SIZE;
rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn);
break;
default:
rc = VM_FAULT_SIGBUS;
}
- if (rc == VM_FAULT_NOPAGE)
- dax_set_mapping(vmf, pfn, fault_size);
dax_read_unlock(id);
return rc;
_
