vfio: Move iova_bitmap into iommufd

Both VFIO and IOMMUFD will need iova bitmap for storing dirties and walking
the user bitmaps, so move to the common dependency into IOMMUFD.  In doing
so, create the symbol IOMMUFD_DRIVER which designates the builtin code that
will be used by drivers when selected. Today this means MLX5_VFIO_PCI and
PDS_VFIO_PCI. IOMMU drivers will do the same (in future patches) when
supporting dirty tracking and select IOMMUFD_DRIVER accordingly.

Given that the symbol maybe be disabled, add header definitions in
iova_bitmap.h for when IOMMUFD_DRIVER=n

Link: https://lore.kernel.org/r/20231024135109.73787-3-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/include/linux/iova_bitmap.h b/include/linux/iova_bitmap.h
index c006cf0a25f3..1c338f5e5b7a 100644
--- a/include/linux/iova_bitmap.h
+++ b/include/linux/iova_bitmap.h
@@ -7,6 +7,7 @@
 #define _IOVA_BITMAP_H_
 
 #include <linux/types.h>
+#include <linux/errno.h>
 
 struct iova_bitmap;
 
@@ -14,6 +15,7 @@ typedef int (*iova_bitmap_fn_t)(struct iova_bitmap *bitmap,
 				unsigned long iova, size_t length,
 				void *opaque);
 
+#if IS_ENABLED(CONFIG_IOMMUFD_DRIVER)
 struct iova_bitmap *iova_bitmap_alloc(unsigned long iova, size_t length,
 				      unsigned long page_size,
 				      u64 __user *data);
@@ -22,5 +24,29 @@ int iova_bitmap_for_each(struct iova_bitmap *bitmap, void *opaque,
 			 iova_bitmap_fn_t fn);
 void iova_bitmap_set(struct iova_bitmap *bitmap,
 		     unsigned long iova, size_t length);
+#else
+static inline struct iova_bitmap *iova_bitmap_alloc(unsigned long iova,
+						    size_t length,
+						    unsigned long page_size,
+						    u64 __user *data)
+{
+	return NULL;
+}
+
+static inline void iova_bitmap_free(struct iova_bitmap *bitmap)
+{
+}
+
+static inline int iova_bitmap_for_each(struct iova_bitmap *bitmap, void *opaque,
+				       iova_bitmap_fn_t fn)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void iova_bitmap_set(struct iova_bitmap *bitmap,
+				   unsigned long iova, size_t length)
+{
+}
+#endif
 
 #endif