diff --git a/config/kernel-blk-queue.m4 b/config/kernel-blk-queue.m4
index ff2da92e9e..1dced82ce6 100644
--- a/config/kernel-blk-queue.m4
+++ b/config/kernel-blk-queue.m4
@@ -23,8 +23,8 @@ AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_PLUG], [
 ])
 
 dnl #
-dnl # 2.6.32 - 4.11, statically allocated bdi in request_queue
-dnl # 4.12 - x.y, dynamically allocated bdi in request_queue
+dnl # 2.6.32 - 4.11: statically allocated bdi in request_queue
+dnl # 4.12: dynamically allocated bdi in request_queue
 dnl #
 AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE_BDI], [
 	ZFS_LINUX_TEST_SRC([blk_queue_bdi], [
@@ -48,7 +48,7 @@ AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_BDI], [
 ])
 
 dnl #
-dnl # 2.6.32 - 4.x API,
+dnl # 2.6.32 API,
 dnl #   blk_queue_discard()
 dnl #
 AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE_DISCARD], [
@@ -71,7 +71,7 @@ AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_DISCARD], [
 ])
 
 dnl #
-dnl # 4.8 - 4.x API,
+dnl # 4.8 API,
 dnl #   blk_queue_secure_erase()
 dnl #
 dnl # 2.6.36 - 4.7 API,
diff --git a/config/kernel-is_owner_or_cap.m4 b/config/kernel-is_owner_or_cap.m4
index 3c3c6ad224..a90cf3da64 100644
--- a/config/kernel-is_owner_or_cap.m4
+++ b/config/kernel-is_owner_or_cap.m4
@@ -4,6 +4,10 @@ dnl # The is_owner_or_cap() macro was renamed to inode_owner_or_capable(),
 dnl # This is used for permission checks in the xattr and file attribute call
 dnl # paths.
 dnl #
+dnl # 5.12 API change,
+dnl # inode_owner_or_capable() now takes struct user_namespace *
+dnl # to support idmapped mounts
+dnl #
 AC_DEFUN([ZFS_AC_KERNEL_SRC_INODE_OWNER_OR_CAPABLE], [
 	ZFS_LINUX_TEST_SRC([inode_owner_or_capable], [
 		#include <linux/fs.h>
diff --git a/include/os/linux/kernel/linux/blkdev_compat.h b/include/os/linux/kernel/linux/blkdev_compat.h
index 14cae35638..87d5410720 100644
--- a/include/os/linux/kernel/linux/blkdev_compat.h
+++ b/include/os/linux/kernel/linux/blkdev_compat.h
@@ -52,7 +52,7 @@ blk_queue_flag_clear(unsigned int flag, struct request_queue *q)
 #endif
 
 /*
- * 4.7 - 4.x API,
+ * 4.7 API,
  * The blk_queue_write_cache() interface has replaced blk_queue_flush()
  * interface.  However, the new interface is GPL-only thus we implement
  * our own trivial wrapper when the GPL-only version is detected.
@@ -254,7 +254,7 @@ bio_set_bi_error(struct bio *bio, int error)
 #endif /* HAVE_1ARG_BIO_END_IO_T */
 
 /*
- * 4.1 - x.y.z API,
+ * 4.1 API,
  * 3.10.0 CentOS 7.x API,
  *   blkdev_reread_part()
  *
@@ -391,7 +391,7 @@ bio_set_flush(struct bio *bio)
 }
 
 /*
- * 4.8 - 4.x API,
+ * 4.8 API,
  *   REQ_OP_FLUSH
  *
  * 4.8-rc0 - 4.8-rc1,
@@ -421,7 +421,7 @@ bio_is_flush(struct bio *bio)
 }
 
 /*
- * 4.8 - 4.x API,
+ * 4.8 API,
  *   REQ_FUA flag moved to bio->bi_opf
  *
  * 2.6.x - 4.7 API,
@@ -440,7 +440,7 @@ bio_is_fua(struct bio *bio)
 }
 
 /*
- * 4.8 - 4.x API,
+ * 4.8 API,
  *   REQ_OP_DISCARD
  *
  * 2.6.36 - 4.7 API,
@@ -462,7 +462,7 @@ bio_is_discard(struct bio *bio)
 }
 
 /*
- * 4.8 - 4.x API,
+ * 4.8 API,
  *   REQ_OP_SECURE_ERASE
  *
  * 2.6.36 - 4.7 API,
@@ -492,7 +492,7 @@ blk_queue_discard_granularity(struct request_queue *q, unsigned int dg)
 }
 
 /*
- * 4.8 - 4.x API,
+ * 4.8 API,
  *   blk_queue_secure_erase()
  *
  * 2.6.36 - 4.7 API,
diff --git a/module/os/linux/zfs/zpl_file.c b/module/os/linux/zfs/zpl_file.c
index d042783da1..421aebefe4 100644
--- a/module/os/linux/zfs/zpl_file.c
+++ b/module/os/linux/zfs/zpl_file.c
@@ -148,7 +148,7 @@ zpl_aio_fsync(struct kiocb *kiocb, int datasync)
 
 #elif defined(HAVE_FSYNC_RANGE)
 /*
- * Linux 3.1 - 3.x API,
+ * Linux 3.1 API,
  * As of 3.1 the responsibility to call filemap_write_and_wait_range() has
  * been pushed down in to the .fsync() vfs hook.  Additionally, the i_mutex
  * lock is no longer held by the caller, for zfs we don't require the lock