[PATCH 1/3] vfio/type1: change success value of vaddr_get_pfn()

From: Daniel Jordan
Date: Wed Feb 03 2021 - 15:51:21 EST


vaddr_get_pfn() simply returns 0 on success. Have it report the number
of pfns successfully gotten instead, whether from page pinning or
follow_fault_pfn(), which will be used later when batching pinning.

Change the last check in vfio_pin_pages_remote() for consistency with
the other two.

Signed-off-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
---
drivers/vfio/vfio_iommu_type1.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 0b4dedaa9128..4d608bc552a4 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -441,6 +441,10 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
return ret;
}

+/*
+ * Returns the positive number of pfns successfully obtained or a negative
+ * error code.
+ */
static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
int prot, unsigned long *pfn)
{
@@ -457,7 +461,6 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
page, NULL, NULL);
if (ret == 1) {
*pfn = page_to_pfn(page[0]);
- ret = 0;
goto done;
}

@@ -471,8 +474,12 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
if (ret == -EAGAIN)
goto retry;

- if (!ret && !is_invalid_reserved_pfn(*pfn))
- ret = -EFAULT;
+ if (!ret) {
+ if (is_invalid_reserved_pfn(*pfn))
+ ret = 1;
+ else
+ ret = -EFAULT;
+ }
}
done:
mmap_read_unlock(mm);
@@ -498,7 +505,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
return -ENODEV;

ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, pfn_base);
- if (ret)
+ if (ret < 0)
return ret;

pinned++;
@@ -525,7 +532,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
for (vaddr += PAGE_SIZE, iova += PAGE_SIZE; pinned < npage;
pinned++, vaddr += PAGE_SIZE, iova += PAGE_SIZE) {
ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, &pfn);
- if (ret)
+ if (ret < 0)
break;

if (pfn != *pfn_base + pinned ||
@@ -551,7 +558,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
ret = vfio_lock_acct(dma, lock_acct, false);

unpin_out:
- if (ret) {
+ if (ret < 0) {
if (!rsvd) {
for (pfn = *pfn_base ; pinned ; pfn++, pinned--)
put_pfn(pfn, dma->prot);
@@ -595,7 +602,7 @@ static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
return -ENODEV;

ret = vaddr_get_pfn(mm, vaddr, dma->prot, pfn_base);
- if (!ret && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
+ if (ret == 1 && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
ret = vfio_lock_acct(dma, 1, true);
if (ret) {
put_pfn(*pfn_base, dma->prot);
--
2.30.0