On 11/25/21 11:42, Joao Martins wrote:
> On 11/24/21 19:10, Joao Martins wrote:
>> @@ -245,8 +251,6 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
>> rc = VM_FAULT_SIGBUS;
>> }
>>
>> - if (rc == VM_FAULT_NOPAGE)
>> - dax_set_mapping(vmf, pfn, fault_size);
>> dax_read_unlock(id);
>>
>> return rc;
>>
> This last chunk is going to spoof out a new warning because @fault_size in
> dev_dax_huge_fault stops being used after this patch.
> I've added below chunk for the next version (in addition to Christoph comments in
> patch 4):
>
Re-attached as a replacement patch below scissors line.
As mentioned earlier, I'll be respinning v7 series with the comments I got on patch 4 and
this replacement below. But given the build warning yesterday&today, figured I
preemptively attach a replacement for it.
----->8-----
>From 2f4cb25c0a6546a27ced4981f0963546f386caec Mon Sep 17 00:00:00 2001
From: Joao Martins <joao.m.martins@xxxxxxxxxx>
Date: Tue, 23 Nov 2021 06:00:38 -0500
Subject: [PATCH] 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()).
Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
---
drivers/dax/device.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 9c87927d4bc2..19a6b86486ce 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -121,6 +121,8 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
*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(struct dev_dax *dev_dax,
*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(struct dev_dax *dev_dax,
*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(struct vm_fault *vmf,
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(struct vm_fault *vmf,
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;
--
2.17.2
