get_disk renamed to get_disk_and_module in 4.16

As of torvalds/linux@fb6d47a, get_disk
is now get_disk_and_module. Add a configure check to determine
if we need to use get_disk_and_module.

Signed-off-by: Giuseppe Di Natale <[email protected]>

config/kernel-get-disk-and-module.m4

@@ -0,0 +1,19 @@
+dnl #
+dnl # 4.16 API change
+dnl # Verify if get_disk_and_module() symbol is available.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_GET_DISK_AND_MODULE],
+	[AC_MSG_CHECKING([whether get_disk_and_module() is available])
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/genhd.h>
+	], [
+		struct gendisk *disk = NULL;
+                (void) get_disk_and_module(disk);
+	], [get_disk_and_module], [block/genhd.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_GET_DISK_AND_MODULE,
+		    1, [get_disk_and_module() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
+])

config/kernel.m4

@@ -40,6 +40,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_BLK_QUEUE_MAX_SEGMENTS
 	ZFS_AC_KERNEL_BLK_QUEUE_HAVE_BIO_RW_UNPLUG
 	ZFS_AC_KERNEL_BLK_QUEUE_HAVE_BLK_PLUG
+	ZFS_AC_KERNEL_GET_DISK_AND_MODULE
 	ZFS_AC_KERNEL_GET_DISK_RO
 	ZFS_AC_KERNEL_GET_GENDISK
 	ZFS_AC_KERNEL_HAVE_BIO_SET_OP_ATTRS

module/zfs/zvol.c

@@ -1589,7 +1589,11 @@ zvol_probe(dev_t dev, int *part, void *arg)
 	struct kobject *kobj;
 
 	zv = zvol_find_by_dev(dev);
+#ifndef HAVE_GET_DISK_AND_MODULE
 	kobj = zv ? get_disk(zv->zv_disk) : NULL;
+#else
+	kobj = zv ? get_disk_and_module(zv->zv_disk) : NULL;
+#endif
 	ASSERT(zv == NULL || MUTEX_HELD(&zv->zv_state_lock));
 	if (zv)
 		mutex_exit(&zv->zv_state_lock);