Linux 5.16: wait_on_page_bit() no longer available to modules

Instead, linux/pagemap.h offers a number of folio-specific functions to be called instead. In this case, module/os/linux/zfs/zfs_vnops_os.c wants to call wait_on_page_bit(pp, PG_writeback). This gets replaced with folio_wait_bit(folio_page(pp), PG_writeback). This change modifies the code to conditionally compile that if configure identifies th presence of the folio_wait_bit() function. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Coleman Kane <[email protected]> Closes openzfs#12800
tonyhutter · Nov 29, 2021 · c0fb44c · c0fb44c
1 parent ded851b
commit c0fb44c
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diff --git a/config/kernel-pagemap-folio_wait_bit.m4 b/config/kernel-pagemap-folio_wait_bit.m4
@@ -0,0 +1,26 @@
+dnl #
+dnl # Linux 5.16 no longer allows directly calling wait_on_page_bit, and
+dnl # instead requires you to call folio-specific functions. In this case,
+dnl # wait_on_page_bit(pg, PG_writeback) becomes
+dnl # folio_wait_bit(pg, PG_writeback)
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_SRC_PAGEMAP_FOLIO_WAIT_BIT], [
+	ZFS_LINUX_TEST_SRC([pagemap_has_folio_wait_bit], [
+		#include <linux/pagemap.h>
+	],[
+		static struct folio *f = NULL;
+
+		folio_wait_bit(f, PG_writeback);
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_PAGEMAP_FOLIO_WAIT_BIT], [
+	AC_MSG_CHECKING([folio_wait_bit() exists])
+	ZFS_LINUX_TEST_RESULT([pagemap_has_folio_wait_bit], [
+		AC_MSG_RESULT([yes])
+		AC_DEFINE(HAVE_PAGEMAP_FOLIO_WAIT_BIT, 1,
+			[folio_wait_bit() exists])
+	],[
+		AC_MSG_RESULT([no])
+	])
+])
diff --git a/config/kernel.m4 b/config/kernel.m4
@@ -134,6 +134,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
 	ZFS_AC_KERNEL_SRC_SET_SPECIAL_STATE
 	ZFS_AC_KERNEL_SRC_VFS_SET_PAGE_DIRTY_NOBUFFERS
 	ZFS_AC_KERNEL_SRC_STANDALONE_LINUX_STDARG
+	ZFS_AC_KERNEL_SRC_PAGEMAP_FOLIO_WAIT_BIT
 
 	AC_MSG_CHECKING([for available kernel interfaces])
 	ZFS_LINUX_TEST_COMPILE_ALL([kabi])
@@ -241,6 +242,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
 	ZFS_AC_KERNEL_SET_SPECIAL_STATE
 	ZFS_AC_KERNEL_VFS_SET_PAGE_DIRTY_NOBUFFERS
 	ZFS_AC_KERNEL_STANDALONE_LINUX_STDARG
+	ZFS_AC_KERNEL_PAGEMAP_FOLIO_WAIT_BIT
 ])
 
 dnl #

diff --git a/module/os/linux/zfs/zfs_vnops_os.c b/module/os/linux/zfs/zfs_vnops_os.c
@@ -3531,7 +3531,11 @@ zfs_putpage(struct inode *ip, struct page *pp, struct writeback_control *wbc)
 
 		if (wbc->sync_mode != WB_SYNC_NONE) {
 			if (PageWriteback(pp))
+#ifdef HAVE_PAGEMAP_FOLIO_WAIT_BIT
+				folio_wait_bit(page_folio(pp), PG_writeback);
+#else
 				wait_on_page_bit(pp, PG_writeback);
+#endif
 		}
 
 		ZFS_EXIT(zfsvfs);