linux-kernel - [PATCH v2 1/4] mm: consolidate dax / non-dax checks for writeback

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Date:   Wed, 26 Jul 2017 13:55:35 -0400
From:   Jeff Layton <jlayton@...nel.org>
To:     Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>
Cc:     "J . Bruce Fields" <bfields@...ldses.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, Matthew Wilcox <willy@...radead.org>,
        Bob Peterson <rpeterso@...hat.com>,
        Steven Whitehouse <swhiteho@...hat.com>,
        cluster-devel@...hat.com
Subject: [PATCH v2 1/4] mm: consolidate dax / non-dax checks for writeback

From: Jeff Layton <jlayton@...hat.com>

We have this complex conditional copied to several places. Turn it into
a helper function.

Signed-off-by: Jeff Layton <jlayton@...hat.com>
---
 mm/filemap.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index e1cca770688f..72e46e6f0d9a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -522,12 +522,17 @@ int filemap_fdatawait(struct address_space *mapping)
 }
 EXPORT_SYMBOL(filemap_fdatawait);
 
+static bool mapping_needs_writeback(struct address_space *mapping)
+{
+	return (!dax_mapping(mapping) && mapping->nrpages) ||
+	    (dax_mapping(mapping) && mapping->nrexceptional);
+}
+
 int filemap_write_and_wait(struct address_space *mapping)
 {
 	int err = 0;
 
-	if ((!dax_mapping(mapping) && mapping->nrpages) ||
-	    (dax_mapping(mapping) && mapping->nrexceptional)) {
+	if (mapping_needs_writeback(mapping)) {
 		err = filemap_fdatawrite(mapping);
 		/*
 		 * Even if the above returned error, the pages may be
@@ -566,8 +571,7 @@ int filemap_write_and_wait_range(struct address_space *mapping,
 {
 	int err = 0;
 
-	if ((!dax_mapping(mapping) && mapping->nrpages) ||
-	    (dax_mapping(mapping) && mapping->nrexceptional)) {
+	if (mapping_needs_writeback(mapping)) {
 		err = __filemap_fdatawrite_range(mapping, lstart, lend,
 						 WB_SYNC_ALL);
 		/* See comment of filemap_write_and_wait() */
@@ -656,8 +660,7 @@ int file_write_and_wait_range(struct file *file, loff_t lstart, loff_t lend)
 	int err = 0, err2;
 	struct address_space *mapping = file->f_mapping;
 
-	if ((!dax_mapping(mapping) && mapping->nrpages) ||
-	    (dax_mapping(mapping) && mapping->nrexceptional)) {
+	if (mapping_needs_writeback(mapping)) {
 		err = __filemap_fdatawrite_range(mapping, lstart, lend,
 						 WB_SYNC_ALL);
 		/* See comment of filemap_write_and_wait() */
-- 
2.13.3