iommufd/iova_bitmap: Cache mapped length in iova_bitmap_map struct

The amount of IOVA mapped will be used more often in iova_bitmap_set() in
preparation to dynamically iterate the bitmap. Cache said length to avoid
having to calculate it all the time.

Link: https://lore.kernel.org/r/20240627110105.62325-8-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 e33ddfc239b5bd76ed6da12fa0a49b14e7f68c6a..2b87ea16ad669af5b36c1abf0923ac994f021495 100644 (file)
--- a/drivers/iommu/iommufd/iova_bitmap.c
+++ b/drivers/iommu/iommufd/iova_bitmap.c
@@ -35,6 +35,9 @@ struct iova_bitmap_map {
        /* base IOVA representing bit 0 of the first page */
        unsigned long iova;
 
+       /* mapped length */
+       unsigned long length;
+
        /* page size order that each bit granules to */
        unsigned long pgshift;
 
@@ -156,6 +159,8 @@ static unsigned long iova_bitmap_mapped_iova(struct iova_bitmap *bitmap)
        return bitmap->iova + iova_bitmap_index_to_offset(bitmap, skip);
 }
 
+static unsigned long iova_bitmap_mapped_length(struct iova_bitmap *bitmap);
+
 /*
  * Pins the bitmap user pages for the current range window.
  * This is internal to IOVA bitmap and called when advancing the
@@ -206,6 +211,7 @@ static int iova_bitmap_get(struct iova_bitmap *bitmap)
         * aligned.
         */
        mapped->pgoff = offset_in_page(addr);
+       mapped->length = iova_bitmap_mapped_length(bitmap);
        return 0;
 }