From c2c2e7bb8b7c269904777b61f4b0a678f1ffb9a3 Mon Sep 17 00:00:00 2001
From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Fri, 27 May 2022 20:44:43 +0000
Subject: [PATCH] Linux 5.19 compat: aops->read_folio()

As of the Linux 5.19 kernel the readpage() address space operation
has been replaced by read_folio().

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #13515
---
 config/kernel-vfs-read_folio.m4 | 32 ++++++++++++++++++++++++++++++++
 config/kernel.m4                |  2 ++
 module/os/linux/zfs/zpl_file.c  | 12 ++++++++++++
 3 files changed, 46 insertions(+)
 create mode 100644 config/kernel-vfs-read_folio.m4

diff --git a/config/kernel-vfs-read_folio.m4 b/config/kernel-vfs-read_folio.m4
new file mode 100644
index 000000000..234d1212a
--- /dev/null
+++ b/config/kernel-vfs-read_folio.m4
@@ -0,0 +1,32 @@
+dnl #
+dnl # Linux 5.19 uses read_folio in lieu of readpage
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_SRC_VFS_READ_FOLIO], [
+	ZFS_LINUX_TEST_SRC([vfs_has_read_folio], [
+		#include <linux/fs.h>
+
+		static int
+		test_read_folio(struct file *file, struct folio *folio) {
+			(void) file; (void) folio;
+			return (0);
+		}
+
+		static const struct address_space_operations
+		    aops __attribute__ ((unused)) = {
+			.read_folio	= test_read_folio,
+		};
+	],[])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_VFS_READ_FOLIO], [
+	dnl #
+	dnl # Linux 5.19 uses read_folio in lieu of readpage
+	dnl #
+	AC_MSG_CHECKING([read_folio exists])
+	ZFS_LINUX_TEST_RESULT([vfs_has_read_folio], [
+		AC_MSG_RESULT([yes])
+		AC_DEFINE(HAVE_VFS_READ_FOLIO, 1, [read_folio exists])
+	],[
+		AC_MSG_RESULT([no])
+	])
+])
diff --git a/config/kernel.m4 b/config/kernel.m4
index a70db91a8..eba3c0669 100644
--- a/config/kernel.m4
+++ b/config/kernel.m4
@@ -102,6 +102,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
 	ZFS_AC_KERNEL_SRC_SGET
 	ZFS_AC_KERNEL_SRC_LSEEK_EXECUTE
 	ZFS_AC_KERNEL_SRC_VFS_FILEMAP_DIRTY_FOLIO
+	ZFS_AC_KERNEL_SRC_VFS_READ_FOLIO
 	ZFS_AC_KERNEL_SRC_VFS_GETATTR
 	ZFS_AC_KERNEL_SRC_VFS_FSYNC_2ARGS
 	ZFS_AC_KERNEL_SRC_VFS_ITERATE
@@ -219,6 +220,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
 	ZFS_AC_KERNEL_SGET
 	ZFS_AC_KERNEL_LSEEK_EXECUTE
 	ZFS_AC_KERNEL_VFS_FILEMAP_DIRTY_FOLIO
+	ZFS_AC_KERNEL_VFS_READ_FOLIO
 	ZFS_AC_KERNEL_VFS_GETATTR
 	ZFS_AC_KERNEL_VFS_FSYNC_2ARGS
 	ZFS_AC_KERNEL_VFS_ITERATE
diff --git a/module/os/linux/zfs/zpl_file.c b/module/os/linux/zfs/zpl_file.c
index 8b84eb795..9a640fb40 100644
--- a/module/os/linux/zfs/zpl_file.c
+++ b/module/os/linux/zfs/zpl_file.c
@@ -674,11 +674,19 @@ zpl_readpage_common(struct page *pp)
 	return (error);
 }
 
+#ifdef HAVE_VFS_READ_FOLIO
+static int
+zpl_read_folio(struct file *filp, struct folio *folio)
+{
+	return (zpl_readpage_common(&folio->page));
+}
+#else
 static int
 zpl_readpage(struct file *filp, struct page *pp)
 {
 	return (zpl_readpage_common(pp));
 }
+#endif
 
 static int
 zpl_readpage_filler(void *data, struct page *pp)
@@ -1208,7 +1216,11 @@ const struct address_space_operations zpl_address_space_operations = {
 #else
 	.readahead	= zpl_readahead,
 #endif
+#ifdef HAVE_VFS_READ_FOLIO
+	.read_folio	= zpl_read_folio,
+#else
 	.readpage	= zpl_readpage,
+#endif
 	.writepage	= zpl_writepage,
 	.writepages	= zpl_writepages,
 	.direct_IO	= zpl_direct_IO,