[PATCH v3] dax: Change return type to vm_fault_t

[Souptick Joarder]

Use new return type vm_fault_t for fault and huge_fault
handler. For now, this is just documenting that the
function returns a VM_FAULT value rather than an errno.
Once all instances are converted, vm_fault_t will become
a distinct type.

Reference id -> 1c8f422059ae ("mm: change return type to
vm_fault_t")

Previously vm_insert_mixed() returns err which driver
mapped into VM_FAULT_* type. The new function 
vmf_insert_mixed() will replace this inefficiency by
returning VM_FAULT_* type.

Signed-off-by: Souptick Joarder <jrdr.li...@gmail.com>
Reviewed-by: Matthew Wilcox <mawil...@microsoft.com>
Reviewed-by: Ross Zwisler <ross.zwis...@linux.intel.com>
---
v2: Modified the change log

v3: Updated the change log and
    added Ross in review list

 drivers/dax/device.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 2137dbc..a122701 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -243,11 +243,11 @@ __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax 
*dev_dax, pgoff_t pgoff,
        return -1;
 }
 
-static int __dev_dax_pte_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
+static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
+                               struct vm_fault *vmf)
 {
        struct device *dev = &dev_dax->dev;
        struct dax_region *dax_region;
-       int rc = VM_FAULT_SIGBUS;
        phys_addr_t phys;
        pfn_t pfn;
        unsigned int fault_size = PAGE_SIZE;
@@ -274,17 +274,11 @@ static int __dev_dax_pte_fault(struct dev_dax *dev_dax, 
struct vm_fault *vmf)
 
        pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
 
-       rc = vm_insert_mixed(vmf->vma, vmf->address, pfn);
-
-       if (rc == -ENOMEM)
-               return VM_FAULT_OOM;
-       if (rc < 0 && rc != -EBUSY)
-               return VM_FAULT_SIGBUS;
-
-       return VM_FAULT_NOPAGE;
+       return vmf_insert_mixed(vmf->vma, vmf->address, pfn);
 }
 
-static int __dev_dax_pmd_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
+static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
+                               struct vm_fault *vmf)
 {
        unsigned long pmd_addr = vmf->address & PMD_MASK;
        struct device *dev = &dev_dax->dev;
@@ -335,7 +329,8 @@ static int __dev_dax_pmd_fault(struct dev_dax *dev_dax, 
struct vm_fault *vmf)
 }
 
 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
-static int __dev_dax_pud_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
+static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
+                               struct vm_fault *vmf)
 {
        unsigned long pud_addr = vmf->address & PUD_MASK;
        struct device *dev = &dev_dax->dev;
@@ -386,13 +381,14 @@ static int __dev_dax_pud_fault(struct dev_dax *dev_dax, 
struct vm_fault *vmf)
                        vmf->flags & FAULT_FLAG_WRITE);
 }
 #else
-static int __dev_dax_pud_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
+static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
+                               struct vm_fault *vmf)
 {
        return VM_FAULT_FALLBACK;
 }
 #endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 
-static int dev_dax_huge_fault(struct vm_fault *vmf,
+static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
                enum page_entry_size pe_size)
 {
        int rc, id;
@@ -423,7 +419,7 @@ static int dev_dax_huge_fault(struct vm_fault *vmf,
        return rc;
 }
 
-static int dev_dax_fault(struct vm_fault *vmf)
+static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
 {
        return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
 }
-- 
1.9.1

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