From bce21a2b48ede7cbcab92db18bc956daf1d5c246 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Wed, 10 Mar 2021 11:45:26 +0100 Subject: Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF} It's not helpful if every driver has to cook its own. Generalize xenbus'es INVALID_GRANT_HANDLE and pcifront's INVALID_GRANT_REF (which shouldn't have expanded to zero to begin with). Use the constants in p2m.c and gntdev.c right away, and update field types where necessary so they would match with the constants' types (albeit without touching struct ioctl_gntdev_grant_ref's ref field, as that's part of the public interface of the kernel and would require introducing a dependency on Xen's grant_table.h public header). Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/db7c38a5-0d75-d5d1-19de-e5fe9f0b9c48@suse.com Signed-off-by: Boris Ostrovsky --- include/xen/grant_table.h | 7 +++++++ include/xen/xenbus.h | 1 - 2 files changed, 7 insertions(+), 1 deletion(-) (limited to 'include/xen') diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index 0b1182a3cf41..cb854df031ce 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -50,6 +50,13 @@ #include #include +/* + * Technically there's no reliably invalid grant reference or grant handle, + * so pick the value that is the most unlikely one to be observed valid. + */ +#define INVALID_GRANT_REF ((grant_ref_t)-1) +#define INVALID_GRANT_HANDLE ((grant_handle_t)-1) + #define GNTTAB_RESERVED_XENSTORE 1 /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */ diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h index 0b1386073d49..b94074c82772 100644 --- a/include/xen/xenbus.h +++ b/include/xen/xenbus.h @@ -51,7 +51,6 @@ #define XENBUS_MAX_RING_GRANT_ORDER 4 #define XENBUS_MAX_RING_GRANTS (1U << XENBUS_MAX_RING_GRANT_ORDER) -#define INVALID_GRANT_HANDLE (~0U) /* Register callback to watch this node. */ struct xenbus_watch -- cgit v1.2.3