jffs2: Use a folio in jffs2_garbage_collect_dnode()

Call read_cache_folio() instead of read_cache_page() to get the folio
containing the page.  No attempt is made here to support large folios
as I assume that will never be interesting for jffs2.  Includes a switch
from kmap to kmap_local which looks safe.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20240814195915.249871-3-willy@infradead.org
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/jffs2/gc.c b/fs/jffs2/gc.c
index 5c6602f3c1891541c5b552f035b5f646bc54128d..822949d0eb00517758bea7e17aaeae0d699fe39a 100644 (file)
--- a/fs/jffs2/gc.c
+++ b/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;
 }