iommufd/iova_bitmap: Check iova_bitmap_done() after set ahead

After iova_bitmap_set_ahead() returns it may be at the end of the range.
Move iova_bitmap_set_ahead() earlier to avoid unnecessary attempt in
trying to pin the next pages by reusing iova_bitmap_done() check.

Fixes: 2780025e01e2 ("iommufd/iova_bitmap: Handle recording beyond the mapped pages")
Link: https://lore.kernel.org/r/20240627110105.62325-7-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Matt Ochs <mochs@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/iommu/iommufd/iova_bitmap.c b/drivers/iommu/iommufd/iova_bitmap.c
index db8c46bee1559ac46fb148d2474668b5a994ae15..e33ddfc239b5bd76ed6da12fa0a49b14e7f68c6a 100644 (file)
--- a/drivers/iommu/iommufd/iova_bitmap.c
+++ b/drivers/iommu/iommufd/iova_bitmap.c
@@ -384,8 +384,6 @@ static int iova_bitmap_advance(struct iova_bitmap *bitmap)
        bitmap->mapped_base_index += count;
 
        iova_bitmap_put(bitmap);
-       if (iova_bitmap_done(bitmap))
-               return 0;
 
        /* Iterate, set and skip any bits requested for next iteration */
        if (bitmap->set_ahead_length) {
@@ -396,6 +394,9 @@ static int iova_bitmap_advance(struct iova_bitmap *bitmap)
                        return ret;
        }
 
+       if (iova_bitmap_done(bitmap))
+               return 0;
+
        /* When advancing the index we pin the next set of bitmap pages */
        return iova_bitmap_get(bitmap);
 }