Merge patch series "Finish converting jffs2 to folios"

Matthew Wilcox (Oracle) <willy@infradead.org> says:

This patch series applies on top of fs-next. After applying these two
patches, there are no more references to 'struct page' in jffs2.  I
obviously haven't tested it at all beyond compilation.

* patches from https://lore.kernel.org/r/20240814195915.249871-1-willy@infradead.org:
  jffs2: Use a folio in jffs2_garbage_collect_dnode()
  jffs2: Convert jffs2_do_readpage_nolock to take a folio

Link: https://lore.kernel.org/r/20240814195915.249871-1-willy@infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/jffs2/file.c

@@ -77,37 +77,35 @@ const struct address_space_operations jffs2_file_address_operations =
 	.write_end =	jffs2_write_end,
 };
 
-static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
+static int jffs2_do_readpage_nolock(struct inode *inode, struct folio *folio)
 {
 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
-	unsigned char *pg_buf;
+	unsigned char *kaddr;
 	int ret;
 
 	jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
-		  __func__, inode->i_ino, pg->index << PAGE_SHIFT);
+		  __func__, inode->i_ino, folio->index << PAGE_SHIFT);
 
-	BUG_ON(!PageLocked(pg));
+	BUG_ON(!folio_test_locked(folio));
 
-	pg_buf = kmap(pg);
-	/* FIXME: Can kmap fail? */
-
-	ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT,
+	kaddr = kmap_local_folio(folio, 0);
+	ret = jffs2_read_inode_range(c, f, kaddr, folio->index << PAGE_SHIFT,
 				     PAGE_SIZE);
+	kunmap_local(kaddr);
 
 	if (!ret)
-		SetPageUptodate(pg);
+		folio_mark_uptodate(folio);
 
-	flush_dcache_page(pg);
-	kunmap(pg);
+	flush_dcache_folio(folio);
 
 	jffs2_dbg(2, "readpage finished\n");
 	return ret;
 }
 
 int __jffs2_read_folio(struct file *file, struct folio *folio)
 {
-	int ret = jffs2_do_readpage_nolock(folio->mapping->host, &folio->page);
+	int ret = jffs2_do_readpage_nolock(folio->mapping->host, folio);
 	folio_unlock(folio);
 	return ret;
 }
@@ -221,7 +219,7 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 	 */
 	if (!folio_test_uptodate(folio)) {
 		mutex_lock(&f->sem);
-		ret = jffs2_do_readpage_nolock(inode, &folio->page);
+		ret = jffs2_do_readpage_nolock(inode, folio);
 		mutex_unlock(&f->sem);
 		if (ret) {
 			folio_unlock(folio);

fs/jffs2/gc.c

@@ -1171,7 +1171,7 @@ static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_era
 	uint32_t alloclen, offset, orig_end, orig_start;
 	int ret = 0;
 	unsigned char *comprbuf = NULL, *writebuf;
-	struct page *page;
+	struct folio *folio;
 	unsigned char *pg_ptr;
 
 	memset(&ri, 0, sizeof(ri));
@@ -1317,25 +1317,25 @@ static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_era
 		BUG_ON(start > orig_start);
 	}
 
-	/* The rules state that we must obtain the page lock *before* f->sem, so
+	/* The rules state that we must obtain the folio lock *before* f->sem, so
 	 * drop f->sem temporarily. Since we also hold c->alloc_sem, nothing's
 	 * actually going to *change* so we're safe; we only allow reading.
 	 *
 	 * It is important to note that jffs2_write_begin() will ensure that its
-	 * page is marked Uptodate before allocating space. That means that if we
-	 * end up here trying to GC the *same* page that jffs2_write_begin() is
-	 * trying to write out, read_cache_page() will not deadlock. */
+	 * folio is marked uptodate before allocating space. That means that if we
+	 * end up here trying to GC the *same* folio that jffs2_write_begin() is
+	 * trying to write out, read_cache_folio() will not deadlock. */
 	mutex_unlock(&f->sem);
-	page = read_cache_page(inode->i_mapping, start >> PAGE_SHIFT,
+	folio = read_cache_folio(inode->i_mapping, start >> PAGE_SHIFT,
 			       __jffs2_read_folio, NULL);
-	if (IS_ERR(page)) {
-		pr_warn("read_cache_page() returned error: %ld\n",
-			PTR_ERR(page));
+	if (IS_ERR(folio)) {
+		pr_warn("read_cache_folio() returned error: %ld\n",
+			PTR_ERR(folio));
 		mutex_lock(&f->sem);
-		return PTR_ERR(page);
+		return PTR_ERR(folio);
 	}
 
-	pg_ptr = kmap(page);
+	pg_ptr = kmap_local_folio(folio, 0);
 	mutex_lock(&f->sem);
 
 	offset = start;
@@ -1400,7 +1400,6 @@ static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_era
 		}
 	}
 
-	kunmap(page);
-	put_page(page);
+	folio_release_kmap(folio, pg_ptr);
 	return ret;
 }