diff options
| author | Dave Airlie <airlied@redhat.com> | 2022-02-14 10:52:27 +1000 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2022-02-14 10:52:27 +1000 |
| commit | b9c7babe2c2e37a50aa42401b38d597ea78f506e (patch) | |
| tree | dd6ec30f2583f8860e69a74e4779ac20e3f53bff /include/uapi/xen/gntdev.h | |
| parent | 123db17ddff007080d464e785689fb14f94cbc7a (diff) | |
| parent | 754e0b0e35608ed5206d6a67a791563c631cec07 (diff) | |
Backmerge tag 'v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into drm-next
Daniel asked for this for some intel deps, so let's do it now.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'include/uapi/xen/gntdev.h')
| -rw-r--r-- | include/uapi/xen/gntdev.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/include/uapi/xen/gntdev.h b/include/uapi/xen/gntdev.h index 9ac5515b9bc2..7a7145395c09 100644 --- a/include/uapi/xen/gntdev.h +++ b/include/uapi/xen/gntdev.h @@ -47,7 +47,13 @@ struct ioctl_gntdev_grant_ref { /* * Inserts the grant references into the mapping table of an instance * of gntdev. N.B. This does not perform the mapping, which is deferred - * until mmap() is called with @index as the offset. + * until mmap() is called with @index as the offset. @index should be + * considered opaque to userspace, with one exception: if no grant + * references have ever been inserted into the mapping table of this + * instance, @index will be set to 0. This is necessary to use gntdev + * with userspace APIs that expect a file descriptor that can be + * mmap()'d at offset 0, such as Wayland. If @count is set to 0, this + * ioctl will fail. */ #define IOCTL_GNTDEV_MAP_GRANT_REF \ _IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref)) |