[PATCH V4 2/4] xen: irqfd: Use _IOW instead of the internal _IOC() macro

[Viresh Kumar <viresh.kumar@xxxxxxxxxx>]

_IOC() an internal helper that we should not use in driver code.  In
particular, we got the data direction wrong here, which breaks a number
of tools, as having "_IOC_NONE" should never be paired with a nonzero
size.

Use _IOW() instead.

Fixes: f8941e6c4c71 ("xen: privcmd: Add support for irqfd")
Reported-by: Arnd Bergmann <arnd@xxxxxxxxxx>
Closes: 
https://lore.kernel.org/all/268a2031-63b8-4c7d-b1e5-8ab83ca80b4a@xxxxxxxxxxxxxxxx/
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
 include/uapi/xen/privcmd.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/xen/privcmd.h b/include/uapi/xen/privcmd.h
index b143fafce84d..e145bca5105c 100644
--- a/include/uapi/xen/privcmd.h
+++ b/include/uapi/xen/privcmd.h
@@ -138,6 +138,6 @@ struct privcmd_irqfd {
 #define IOCTL_PRIVCMD_MMAP_RESOURCE                            \
        _IOC(_IOC_NONE, 'P', 7, sizeof(struct privcmd_mmap_resource))
 #define IOCTL_PRIVCMD_IRQFD                                    \
-       _IOC(_IOC_NONE, 'P', 8, sizeof(struct privcmd_irqfd))
+       _IOW('P', 8, struct privcmd_irqfd)
 
 #endif /* __LINUX_PUBLIC_PRIVCMD_H__ */
-- 
2.31.1.272.g89b43f80a514