[PATCH 04/10] x86: Convert vdso to use vm_fault_t

From: Matthew Wilcox
Date: Tue Aug 28 2018 - 10:58:23 EST


Return vm_fault_t codes directly from the appropriate mm routines instead
of converting from errnos ourselves. Fixes a minor bug where we'd return
SIGBUS instead of the correct OOM code if we ran out of memory allocating
page tables.

Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/entry/vdso/vma.c | 24 +++++++++---------------
1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 5b8b556dbb12..d1daa53215a4 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;
@@ -84,12 +84,11 @@ 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;

if (!image)
return VM_FAULT_SIGBUS;
@@ -108,29 +107,24 @@ static int vvar_fault(const struct vm_special_mapping *sm,
return VM_FAULT_SIGBUS;

if (sym_offset == image->sym_vvar_page) {
- ret = vm_insert_pfn(vma, vmf->address,
- __pa_symbol(&__vvar_page) >> PAGE_SHIFT);
+ return 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 =
pvclock_get_pvti_cpu0_va();
if (pvti && vclock_was_used(VCLOCK_PVCLOCK)) {
- ret = vm_insert_pfn_prot(
- vma,
- vmf->address,
- __pa(pvti) >> PAGE_SHIFT,
- pgprot_decrypted(vma->vm_page_prot));
+ return vmf_insert_pfn_prot(vma, vmf->address,
+ __pa(pvti) >> PAGE_SHIFT,
+ pgprot_decrypted(vma->vm_page_prot));
}
} else if (sym_offset == image->sym_hvclock_page) {
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,
- vmalloc_to_pfn(tsc_pg));
+ return vmf_insert_pfn(vma, vmf->address,
+ vmalloc_to_pfn(tsc_pg));
}

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

--
2.18.0