On 11/29/21 15:49, Joao Martins wrote:
> On 11/29/21 07:32, Christoph Hellwig wrote:
>> On Fri, Nov 26, 2021 at 06:39:39PM +0000, Joao Martins wrote:
>> Aso it seems like pfn is only an input
>> parameter now and doesn't need to be passed by reference.
>>
> It's actually just an output parameter (that dax_set_mapping would then use).
>
> The fault handlers in device-dax use vmf->address to calculate pfn that they
> insert in the page table entry. After this patch we can actually just remove
> @pfn argument.
I've added your suggestion as a cleanup patch between 9 and current 10 (11 in v7):
---->8----
>From 999cec9efa757b82f435124518b042caeb51bde6 Mon Sep 17 00:00:00 2001
From: Joao Martins <joao.m.martins@xxxxxxxxxx>
Date: Mon, 29 Nov 2021 11:12:00 -0500
Subject: [PATCH] device-dax: remove pfn from __dev_dax_{pte,pmd,pud}_fault()
After moving the page mapping to be set prior to pte insertion, the pfn
in dev_dax_huge_fault() no longer is necessary. Remove it, as well as
the @pfn argument passed to the internal fault handler helpers.
Suggested-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
---
drivers/dax/device.c | 34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 19a6b86486ce..914368164e05 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -95,10 +95,11 @@ static void dax_set_mapping(struct vm_fault *vmf, pfn_t pfn,
}
static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
- struct vm_fault *vmf, pfn_t *pfn)
+ struct vm_fault *vmf)
{
struct device *dev = &dev_dax->dev;
phys_addr_t phys;
+ pfn_t pfn;
unsigned int fault_size = PAGE_SIZE;
if (check_vma(dev_dax, vmf->vma, __func__))
@@ -119,20 +120,21 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
return VM_FAULT_SIGBUS;
}
- *pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
+ pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
- dax_set_mapping(vmf, *pfn, fault_size);
+ dax_set_mapping(vmf, pfn, fault_size);
- 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, pfn_t *pfn)
+ struct vm_fault *vmf)
{
unsigned long pmd_addr = vmf->address & PMD_MASK;
struct device *dev = &dev_dax->dev;
phys_addr_t phys;
pgoff_t pgoff;
+ pfn_t pfn;
unsigned int fault_size = PMD_SIZE;
if (check_vma(dev_dax, vmf->vma, __func__))
@@ -161,21 +163,22 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
return VM_FAULT_SIGBUS;
}
- *pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
+ pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
- dax_set_mapping(vmf, *pfn, fault_size);
+ dax_set_mapping(vmf, pfn, fault_size);
- return vmf_insert_pfn_pmd(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE);
+ return vmf_insert_pfn_pmd(vmf, 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, pfn_t *pfn)
+ struct vm_fault *vmf)
{
unsigned long pud_addr = vmf->address & PUD_MASK;
struct device *dev = &dev_dax->dev;
phys_addr_t phys;
pgoff_t pgoff;
+ pfn_t pfn;
unsigned int fault_size = PUD_SIZE;
@@ -205,11 +208,11 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
return VM_FAULT_SIGBUS;
}
- *pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
+ pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
- dax_set_mapping(vmf, *pfn, fault_size);
+ dax_set_mapping(vmf, pfn, fault_size);
- return vmf_insert_pfn_pud(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE);
+ return vmf_insert_pfn_pud(vmf, pfn, vmf->flags & FAULT_FLAG_WRITE);
}
#else
static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
@@ -225,7 +228,6 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
struct file *filp = vmf->vma->vm_file;
vm_fault_t rc = VM_FAULT_SIGBUS;
int 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,
@@ -235,13 +237,13 @@ 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, &pfn);
+ rc = __dev_dax_pte_fault(dev_dax, vmf);
break;
case PE_SIZE_PMD:
- rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn);
+ rc = __dev_dax_pmd_fault(dev_dax, vmf);
break;
case PE_SIZE_PUD:
- rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn);
+ rc = __dev_dax_pud_fault(dev_dax, vmf);
break;
default:
rc = VM_FAULT_SIGBUS;
--
2.17.2
