f2fs: simplify page iteration loops

In several places we want to iterate over all tagged pages in a mapping.
However the code was apparently copied from places that iterate only
over a limited range and thus it checks for index <= end, optimizes the
case where we are coming close to range end which is all pointless when
end == ULONG_MAX.  So just remove this dead code.

[akpm@linux-foundation.org: fix warnings]
Link: http://lkml.kernel.org/r/20171009151359.31984-7-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 04fe1df..fb74ec4 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -305,9 +305,10 @@ long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
                                long nr_to_write, enum iostat_type io_type)
 {
        struct address_space *mapping = META_MAPPING(sbi);
-       pgoff_t index = 0, end = ULONG_MAX, prev = ULONG_MAX;
+       pgoff_t index = 0, prev = ULONG_MAX;
        struct pagevec pvec;
        long nwritten = 0;
+       int nr_pages;
        struct writeback_control wbc = {
                .for_reclaim = 0,
        };
@@ -317,13 +318,9 @@ long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
 
        blk_start_plug(&plug);
 
-       while (index <= end) {
-               int i, nr_pages;
-               nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
-                               PAGECACHE_TAG_DIRTY,
-                               min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
-               if (unlikely(nr_pages == 0))
-                       break;
+       while ((nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+                               PAGECACHE_TAG_DIRTY, PAGEVEC_SIZE))) {
+               int i;
 
                for (i = 0; i < nr_pages; i++) {
                        struct page *page = pvec.pages[i];

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index fca8783..ca020e7 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1277,21 +1277,17 @@ release_page:
 
 static struct page *last_fsync_dnode(struct f2fs_sb_info *sbi, nid_t ino)
 {
-       pgoff_t index, end;
+       pgoff_t index;
        struct pagevec pvec;
        struct page *last_page = NULL;
+       int nr_pages;
 
        pagevec_init(&pvec, 0);
        index = 0;
-       end = ULONG_MAX;
-
-       while (index <= end) {
-               int i, nr_pages;
-               nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
-                               PAGECACHE_TAG_DIRTY,
-                               min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
-               if (nr_pages == 0)
-                       break;
+
+       while ((nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
+                               PAGECACHE_TAG_DIRTY, PAGEVEC_SIZE))) {
+               int i;
 
                for (i = 0; i < nr_pages; i++) {
                        struct page *page = pvec.pages[i];
@@ -1425,13 +1421,14 @@ static int f2fs_write_node_page(struct page *page,
 int fsync_node_pages(struct f2fs_sb_info *sbi, struct inode *inode,
                        struct writeback_control *wbc, bool atomic)
 {
-       pgoff_t index, end;
+       pgoff_t index;
        pgoff_t last_idx = ULONG_MAX;
        struct pagevec pvec;
        int ret = 0;
        struct page *last_page = NULL;
        bool marked = false;
        nid_t ino = inode->i_ino;
+       int nr_pages;
 
        if (atomic) {
                last_page = last_fsync_dnode(sbi, ino);
@@ -1441,15 +1438,10 @@ int fsync_node_pages(struct f2fs_sb_info *sbi, struct inode *inode,
 retry:
        pagevec_init(&pvec, 0);
        index = 0;
-       end = ULONG_MAX;
-
-       while (index <= end) {
-               int i, nr_pages;
-               nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
-                               PAGECACHE_TAG_DIRTY,
-                               min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
-               if (nr_pages == 0)
-                       break;
+
+       while ((nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
+                               PAGECACHE_TAG_DIRTY, PAGEVEC_SIZE))) {
+               int i;
 
                for (i = 0; i < nr_pages; i++) {
                        struct page *page = pvec.pages[i];
@@ -1548,25 +1540,21 @@ out:
 int sync_node_pages(struct f2fs_sb_info *sbi, struct writeback_control *wbc,
                                bool do_balance, enum iostat_type io_type)
 {
-       pgoff_t index, end;
+       pgoff_t index;
        struct pagevec pvec;
        int step = 0;
        int nwritten = 0;
        int ret = 0;
+       int nr_pages;
 
        pagevec_init(&pvec, 0);
 
 next_step:
        index = 0;
-       end = ULONG_MAX;
-
-       while (index <= end) {
-               int i, nr_pages;
-               nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
-                               PAGECACHE_TAG_DIRTY,
-                               min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
-               if (nr_pages == 0)
-                       break;
+
+       while ((nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
+                               PAGECACHE_TAG_DIRTY, PAGEVEC_SIZE))) {
+               int i;
 
                for (i = 0; i < nr_pages; i++) {
                        struct page *page = pvec.pages[i];
@@ -1655,27 +1643,20 @@ out:
 
 int wait_on_node_pages_writeback(struct f2fs_sb_info *sbi, nid_t ino)
 {
-       pgoff_t index = 0, end = ULONG_MAX;
+       pgoff_t index = 0;
        struct pagevec pvec;
        int ret2, ret = 0;
+       int nr_pages;
 
        pagevec_init(&pvec, 0);
 
-       while (index <= end) {
-               int i, nr_pages;
-               nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
-                               PAGECACHE_TAG_WRITEBACK,
-                               min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
-               if (nr_pages == 0)
-                       break;
+       while ((nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
+                               PAGECACHE_TAG_WRITEBACK, PAGEVEC_SIZE))) {
+               int i;
 
                for (i = 0; i < nr_pages; i++) {
                        struct page *page = pvec.pages[i];
 
-                       /* until radix tree lookup accepts end_index */
-                       if (unlikely(page->index > end))
-                               continue;
-
                        if (ino && ino_of_node(page) == ino) {
                                f2fs_wait_on_page_writeback(page, NODE, true);
                                if (TestClearPageError(page))