vfio/mdev: consolidate all the available_instance sysfs into the core code

Every driver just print a number, simply add a method to the mdev_driver
to return it and provide a standard sysfs show function.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Link: https://lore.kernel.org/r/20220923092652.100656-13-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index 0b7585f16d8a..6c2cbc4e25ca 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -1361,21 +1361,16 @@ static ssize_t description_show(struct mdev_type *mtype,
 }
 static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
+static unsigned int mbochs_get_available(struct mdev_type *mtype)
 {
 	struct mbochs_type *type =
 		container_of(mtype, struct mbochs_type, type);
-	int count = atomic_read(&mbochs_avail_mbytes) / type->mbytes;
 
-	return sprintf(buf, "%d\n", count);
+	return atomic_read(&mbochs_avail_mbytes) / type->mbytes;
 }
-static MDEV_TYPE_ATTR_RO(available_instances);
 
 static const struct attribute *mdev_types_attrs[] = {
 	&mdev_type_attr_description.attr,
-	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
 
@@ -1399,6 +1394,7 @@ static struct mdev_driver mbochs_driver = {
 	},
 	.probe = mbochs_probe,
 	.remove	= mbochs_remove,
+	.get_available = mbochs_get_available,
 	.types_attrs = mdev_types_attrs,
 };