vfio/type1: fix vaddr_get_pfns() return in vfio_pin_page_external()

vaddr_get_pfns() now returns the positive number of pfns successfully
gotten instead of zero.  vfio_pin_page_external() might return 1 to
vfio_iommu_type1_pin_pages(), which will treat it as an error, if
vaddr_get_pfns() is successful but vfio_pin_page_external() doesn't
reach vfio_lock_acct().

Fix it up in vfio_pin_page_external().  Found by inspection.

Fixes: be16c1fd99f4 ("vfio/type1: Change success value of vaddr_get_pfn()")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Message-Id: <20210308172452.38864-1-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 12d9905b429fd5117353c2d42d6bed3d412222f2..be444407664af74e66d746a52a199513b501efb1 100644 (file)
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -785,7 +785,12 @@ static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
                return -ENODEV;
 
        ret = vaddr_get_pfns(mm, vaddr, 1, dma->prot, pfn_base, pages);
-       if (ret == 1 && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
+       if (ret != 1)
+               goto out;
+
+       ret = 0;
+
+       if (do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
                ret = vfio_lock_acct(dma, 1, true);
                if (ret) {
                        put_pfn(*pfn_base, dma->prot);
@@ -797,6 +802,7 @@ static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
                }
        }
 
+out:
        mmput(mm);
        return ret;
 }