ext4: convert mext_page_double_lock() to mext_folio_double_lock()

Convert mext_page_double_lock() to use folios.  This change saves 146
bytes of kernel text.  It also removes 6 calls to compound_head() and 2
calls to folio_file_page().

Link: https://lkml.kernel.org/r/20221207181009.4016-1-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 8dbb87e..2de9829 100644 (file)
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -110,22 +110,23 @@ out:
 }
 
 /**
- * mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2
+ * mext_folio_double_lock - Grab and lock folio on both @inode1 and @inode2
  *
  * @inode1:    the inode structure
  * @inode2:    the inode structure
- * @index1:    page index
- * @index2:    page index
- * @page:      result page vector
+ * @index1:    folio index
+ * @index2:    folio index
+ * @folio:     result folio vector
  *
- * Grab two locked pages for inode's by inode order
+ * Grab two locked folio for inode's by inode order
  */
 static int
-mext_page_double_lock(struct inode *inode1, struct inode *inode2,
-                     pgoff_t index1, pgoff_t index2, struct page *page[2])
+mext_folio_double_lock(struct inode *inode1, struct inode *inode2,
+                     pgoff_t index1, pgoff_t index2, struct folio *folio[2])
 {
        struct address_space *mapping[2];
        unsigned int flags;
+       unsigned fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE;
 
        BUG_ON(!inode1 || !inode2);
        if (inode1 < inode2) {
@@ -138,28 +139,30 @@ mext_page_double_lock(struct inode *inode1, struct inode *inode2,
        }
 
        flags = memalloc_nofs_save();
-       page[0] = grab_cache_page_write_begin(mapping[0], index1);
-       if (!page[0]) {
+       folio[0] = __filemap_get_folio(mapping[0], index1, fgp_flags,
+                       mapping_gfp_mask(mapping[0]));
+       if (!folio[0]) {
                memalloc_nofs_restore(flags);
                return -ENOMEM;
        }
 
-       page[1] = grab_cache_page_write_begin(mapping[1], index2);
+       folio[1] = __filemap_get_folio(mapping[1], index2, fgp_flags,
+                       mapping_gfp_mask(mapping[1]));
        memalloc_nofs_restore(flags);
-       if (!page[1]) {
-               unlock_page(page[0]);
-               put_page(page[0]);
+       if (!folio[1]) {
+               folio_unlock(folio[0]);
+               folio_put(folio[0]);
                return -ENOMEM;
        }
        /*
-        * grab_cache_page_write_begin() may not wait on page's writeback if
+        * __filemap_get_folio() may not wait on folio's writeback if
         * BDI not demand that. But it is reasonable to be very conservative
-        * here and explicitly wait on page's writeback
+        * here and explicitly wait on folio's writeback
         */
-       wait_on_page_writeback(page[0]);
-       wait_on_page_writeback(page[1]);
+       folio_wait_writeback(folio[0]);
+       folio_wait_writeback(folio[1]);
        if (inode1 > inode2)
-               swap(page[0], page[1]);
+               swap(folio[0], folio[1]);
 
        return 0;
 }
@@ -252,7 +255,6 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
                     int block_len_in_page, int unwritten, int *err)
 {
        struct inode *orig_inode = file_inode(o_filp);
-       struct page *pagep[2] = {NULL, NULL};
        struct folio *folio[2] = {NULL, NULL};
        handle_t *handle;
        ext4_lblk_t orig_blk_offset, donor_blk_offset;
@@ -303,8 +305,8 @@ again:
 
        replaced_size = data_size;
 
-       *err = mext_page_double_lock(orig_inode, donor_inode, orig_page_offset,
-                                    donor_page_offset, pagep);
+       *err = mext_folio_double_lock(orig_inode, donor_inode, orig_page_offset,
+                                    donor_page_offset, folio);
        if (unlikely(*err < 0))
                goto stop_journal;
        /*
@@ -314,8 +316,6 @@ again:
         * hold page's lock, if it is still the case data copy is not
         * necessary, just swap data blocks between orig and donor.
         */
-       folio[0] = page_folio(pagep[0]);
-       folio[1] = page_folio(pagep[1]);
 
        VM_BUG_ON_FOLIO(folio_test_large(folio[0]), folio[0]);
        VM_BUG_ON_FOLIO(folio_test_large(folio[1]), folio[1]);