Linux 5.11 compat: revalidate_disk_size()

Both revalidate_disk_size() and revalidate_disk() have been removed.
Functionally this isn't a problem because we only relied on these
functions to call zvol_revalidate_disk() for us and to perform any
additional handling which might be needed for that kernel version.
When neither are available we know there's no additional handling
needed and we can directly call zvol_revalidate_disk().

Reviewed-by: Rafael Kitover <rkitover@gmail.com>
Reviewed-by: Coleman Kane <ckane@colemankane.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11387
Closes #11390

config/kernel-revalidate-disk-size.m4

@@ -1,24 +1,46 @@
 dnl #
+dnl # 5.11 API change
+dnl # revalidate_disk_size() has been removed entirely.
+dnl #
 dnl # 5.10 API change
 dnl # revalidate_disk() was replaced by revalidate_disk_size()
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_SRC_REVALIDATE_DISK_SIZE], [
+AC_DEFUN([ZFS_AC_KERNEL_SRC_REVALIDATE_DISK], [
+
 	ZFS_LINUX_TEST_SRC([revalidate_disk_size], [
 		#include <linux/genhd.h>
 	], [
 		struct gendisk *disk = NULL;
 		(void) revalidate_disk_size(disk, false);
 	])
+
+	ZFS_LINUX_TEST_SRC([revalidate_disk], [
+		#include <linux/genhd.h>
+	], [
+		struct gendisk *disk = NULL;
+		(void) revalidate_disk(disk);
+	])
 ])
 
-AC_DEFUN([ZFS_AC_KERNEL_REVALIDATE_DISK_SIZE], [
+AC_DEFUN([ZFS_AC_KERNEL_REVALIDATE_DISK], [
+
 	AC_MSG_CHECKING([whether revalidate_disk_size() is available])
 	ZFS_LINUX_TEST_RESULT_SYMBOL([revalidate_disk_size],
 		[revalidate_disk_size], [block/genhd.c], [
 		AC_MSG_RESULT(yes)
 		AC_DEFINE(HAVE_REVALIDATE_DISK_SIZE, 1,
-			[revalidate_disk_size() is available])
+		    [revalidate_disk_size() is available])
 	], [
 		AC_MSG_RESULT(no)
+
+		AC_MSG_CHECKING([whether revalidate_disk() is available])
+		ZFS_LINUX_TEST_RESULT_SYMBOL([revalidate_disk],
+		    [revalidate_disk], [block/genhd.c], [
+			AC_MSG_RESULT(yes)
+			AC_DEFINE(HAVE_REVALIDATE_DISK, 1,
+			    [revalidate_disk() is available])
+		], [
+			AC_MSG_RESULT(no)
+		])
 	])
 ])

config/kernel.m4

@@ -62,7 +62,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
 	ZFS_AC_KERNEL_SRC_BLKDEV
 	ZFS_AC_KERNEL_SRC_BLK_QUEUE
 	ZFS_AC_KERNEL_SRC_GET_DISK_AND_MODULE
-	ZFS_AC_KERNEL_SRC_REVALIDATE_DISK_SIZE
+	ZFS_AC_KERNEL_SRC_REVALIDATE_DISK
 	ZFS_AC_KERNEL_SRC_GET_DISK_RO
 	ZFS_AC_KERNEL_SRC_GENERIC_READLINK_GLOBAL
 	ZFS_AC_KERNEL_SRC_DISCARD_GRANULARITY
@@ -161,7 +161,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
 	ZFS_AC_KERNEL_BLKDEV
 	ZFS_AC_KERNEL_BLK_QUEUE
 	ZFS_AC_KERNEL_GET_DISK_AND_MODULE
-	ZFS_AC_KERNEL_REVALIDATE_DISK_SIZE
+	ZFS_AC_KERNEL_REVALIDATE_DISK
 	ZFS_AC_KERNEL_GET_DISK_RO
 	ZFS_AC_KERNEL_GENERIC_READLINK_GLOBAL
 	ZFS_AC_KERNEL_DISCARD_GRANULARITY

module/os/linux/zfs/zvol_os.c

@@ -658,10 +658,12 @@ zvol_update_volsize(zvol_state_t *zv, uint64_t volsize)
 {
 	struct gendisk *disk = zv->zv_zso->zvo_disk;
 
-#ifdef HAVE_REVALIDATE_DISK_SIZE
+#if defined(HAVE_REVALIDATE_DISK_SIZE)
 	revalidate_disk_size(disk, zvol_revalidate_disk(disk) == 0);
-#else
+#elif defined(HAVE_REVALIDATE_DISK)
 	revalidate_disk(disk);
+#else
+	zvol_revalidate_disk(disk);
 #endif
 	return (0);
 }