vfio/type1: Change success value of vaddr_get_pfn()

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@oracle.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index ed03f3f..82ed8bf 100644 (file)
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -495,6 +495,10 @@ 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)
 {
@@ -511,7 +515,6 @@ 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;
        }
 
@@ -525,8 +528,12 @@ retry:
                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);
@@ -607,7 +614,7 @@ 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++;
@@ -634,7 +641,7 @@ 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 ||
@@ -660,7 +667,7 @@ out:
        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);
@@ -704,7 +711,7 @@ 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);