[PATCH] x86/vdso: Change return type to vm_fault_t for fault handlers

From: Souptick Joarder
Date: Mon Jun 25 2018 - 11:55:44 EST


Use new return type vm_fault_t for 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.

Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")

Previously vm_insert_pfn() returns err which has to
mapped into VM_FAULT_* type. The new function
vmf_insert_pfn() will replace this inefficiency by
returning VM_FAULT_* type.

Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx>
---
arch/x86/entry/vdso/vma.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 5b8b556..3679885 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -39,7 +39,7 @@ void __init init_vdso_image(const struct vdso_image *image)

struct linux_binprm;

-static int vdso_fault(const struct vm_special_mapping *sm,
+static vm_fault_t vdso_fault(const struct vm_special_mapping *sm,
struct vm_area_struct *vma, struct vm_fault *vmf)
{
const struct vdso_image *image = vma->vm_mm->context.vdso_image;
@@ -84,15 +84,15 @@ static int vdso_mremap(const struct vm_special_mapping *sm,
return 0;
}

-static int vvar_fault(const struct vm_special_mapping *sm,
+static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
struct vm_area_struct *vma, struct vm_fault *vmf)
{
const struct vdso_image *image = vma->vm_mm->context.vdso_image;
long sym_offset;
- int ret = -EFAULT;
+ vm_fault_t ret = VM_FAULT_SIGBUS;

if (!image)
- return VM_FAULT_SIGBUS;
+ return ret;

sym_offset = (long)(vmf->pgoff << PAGE_SHIFT) +
image->sym_vvar_start;
@@ -105,10 +105,10 @@ static int vvar_fault(const struct vm_special_mapping *sm,
* the page past the end of the vvar mapping.
*/
if (sym_offset == 0)
- return VM_FAULT_SIGBUS;
+ return ret;

if (sym_offset == image->sym_vvar_page) {
- ret = vm_insert_pfn(vma, vmf->address,
+ ret = vmf_insert_pfn(vma, vmf->address,
__pa_symbol(&__vvar_page) >> PAGE_SHIFT);
} else if (sym_offset == image->sym_pvclock_page) {
struct pvclock_vsyscall_time_info *pvti =
@@ -124,14 +124,11 @@ static int vvar_fault(const struct vm_special_mapping *sm,
struct ms_hyperv_tsc_page *tsc_pg = hv_get_tsc_page();

if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK))
- ret = vm_insert_pfn(vma, vmf->address,
+ ret = vmf_insert_pfn(vma, vmf->address,
vmalloc_to_pfn(tsc_pg));
}

- if (ret == 0 || ret == -EBUSY)
- return VM_FAULT_NOPAGE;
-
- return VM_FAULT_SIGBUS;
+ return ret;
}

static const struct vm_special_mapping vdso_mapping = {
--
1.9.1