Linux 5.2 compat: Directly call wait_on_page_bit()

wait_on_page_writeback() was made GPL only in torvalds/linux@19343b5bdd.

Directly call wait_on_page_bit() without using wait_on_page_writeback()
interface, given zfs_putpage() is the only caller for now.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@osnexus.com>
Closes #8794

diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index 41c1bd255753467a272f0677cbcfae2068a1143a..885d9633b01f7698e5ba85746ad1c340b95f0acd 100644 (file)
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -4526,8 +4526,10 @@ zfs_putpage(struct inode *ip, struct page *pp, struct writeback_control *wbc)
                unlock_page(pp);
                rangelock_exit(lr);
 
-               if (wbc->sync_mode != WB_SYNC_NONE)
-                       wait_on_page_writeback(pp);
+               if (wbc->sync_mode != WB_SYNC_NONE) {
+                       if (PageWriteback(pp))
+                               wait_on_page_bit(pp, PG_writeback);
+               }
 
                ZFS_EXIT(zfsvfs);
                return (0);