[PATCH] vfio-mdev: fix non-standard ioctl return val causing i386 build fail

Paul Gortmaker
2017-01-03T19:37:36Z

What appears to be a copy and paste error from the line above gets
the ioctl a ssize_t return value instead of the traditional "int".

The associated sample code used "long" which meant it would compile
for x86-64 but not i386, with the latter failing as follows:

CC [M] samples/vfio-mdev/mtty.o
samples/vfio-mdev/mtty.c:1418:20: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
.ioctl = mtty_ioctl,
^
samples/vfio-mdev/mtty.c:1418:20: note: (near initialization for ‘mdev_fops.ioctl’)
cc1: some warnings being treated as errors

Use the standard "int" ioctl return value in both the header and
the sample code to fix the issue.

Fixes: 9d1a546c53b4 ("docs: Sample driver to demonstrate how to use Mediated device framework.")
Cc: Kirti Wankhede <kwankhede@nvidia.com>
Cc: Neo Jia <cjia@nvidia.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
include/linux/mdev.h | 2 +-
samples/vfio-mdev/mtty.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 3ee44b8d2bb3..46659572ab00 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -78,7 +78,7 @@ struct mdev_parent_ops {
size_t count, loff_t *ppos);
ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
size_t count, loff_t *ppos);
- ssize_t (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
+ int (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
unsigned long arg);
int (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
};
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 919c10d5b12e..6f0713b1f717 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1147,7 +1147,7 @@ int mtty_get_device_info(struct mdev_device *mdev,
return 0;
}

-static long mtty_ioctl(struct mdev_device *mdev, unsigned int cmd,
+static int mtty_ioctl(struct mdev_device *mdev, unsigned int cmd,
unsigned long arg)
{
int ret = 0;
--
2.11.0