filemap: Convert filemap_get_read_batch() to use a folio_batch

This change ripples all the way through the filemap_read() call chain and
removes a lot of messing about converting folios to pages and back again.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>

diff --git a/mm/filemap.c b/mm/filemap.c
index ea5460e1255563867ef769f85ddb24851464f6b8..aefa6082b81b1ea44e4fcd484fe3cbfbb56b9523 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2325,16 +2325,16 @@ static void shrink_readahead_size_eio(struct file_ra_state *ra)
 }
 
 /*
- * filemap_get_read_batch - Get a batch of pages for read
+ * filemap_get_read_batch - Get a batch of folios for read
  *
- * Get a batch of pages which represent a contiguous range of bytes
- * in the file.  No tail pages will be returned.  If @index is in the
- * middle of a THP, the entire THP will be returned.  The last page in
- * the batch may have Readahead set or be not Uptodate so that the
- * caller can take the appropriate action.
+ * Get a batch of folios which represent a contiguous range of bytes in
+ * the file.  No exceptional entries will be returned.  If @index is in
+ * the middle of a folio, the entire folio will be returned.  The last
+ * folio in the batch may have the readahead flag set or the uptodate flag
+ * clear so that the caller can take the appropriate action.
  */
 static void filemap_get_read_batch(struct address_space *mapping,
-               pgoff_t index, pgoff_t max, struct pagevec *pvec)
+               pgoff_t index, pgoff_t max, struct folio_batch *fbatch)
 {
        XA_STATE(xas, &mapping->i_pages, index);
        struct folio *folio;
@@ -2349,9 +2349,9 @@ static void filemap_get_read_batch(struct address_space *mapping,
                        goto retry;
 
                if (unlikely(folio != xas_reload(&xas)))
-                       goto put_page;
+                       goto put_folio;
 
-               if (!pagevec_add(pvec, &folio->page))
+               if (!folio_batch_add(fbatch, folio))
                        break;
                if (!folio_test_uptodate(folio))
                        break;
@@ -2360,7 +2360,7 @@ static void filemap_get_read_batch(struct address_space *mapping,
                xas.xa_index = folio->index + folio_nr_pages(folio) - 1;
                xas.xa_offset = (xas.xa_index >> xas.xa_shift) & XA_CHUNK_MASK;
                continue;
-put_page:
+put_folio:
                folio_put(folio);
 retry:
                xas_reset(&xas);
@@ -2475,7 +2475,7 @@ unlock_mapping:
 
 static int filemap_create_folio(struct file *file,
                struct address_space *mapping, pgoff_t index,
-               struct pagevec *pvec)
+               struct folio_batch *fbatch)
 {
        struct folio *folio;
        int error;
@@ -2510,7 +2510,7 @@ static int filemap_create_folio(struct file *file,
                goto error;
 
        filemap_invalidate_unlock_shared(mapping);
-       pagevec_add(pvec, &folio->page);
+       folio_batch_add(fbatch, folio);
        return 0;
 error:
        filemap_invalidate_unlock_shared(mapping);
@@ -2531,7 +2531,7 @@ static int filemap_readahead(struct kiocb *iocb, struct file *file,
 }
 
 static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
-               struct pagevec *pvec)
+               struct folio_batch *fbatch)
 {
        struct file *filp = iocb->ki_filp;
        struct address_space *mapping = filp->f_mapping;
@@ -2546,32 +2546,33 @@ retry:
        if (fatal_signal_pending(current))
                return -EINTR;
 
-       filemap_get_read_batch(mapping, index, last_index, pvec);
-       if (!pagevec_count(pvec)) {
+       filemap_get_read_batch(mapping, index, last_index, fbatch);
+       if (!folio_batch_count(fbatch)) {
                if (iocb->ki_flags & IOCB_NOIO)
                        return -EAGAIN;
                page_cache_sync_readahead(mapping, ra, filp, index,
                                last_index - index);
-               filemap_get_read_batch(mapping, index, last_index, pvec);
+               filemap_get_read_batch(mapping, index, last_index, fbatch);
        }
-       if (!pagevec_count(pvec)) {
+       if (!folio_batch_count(fbatch)) {
                if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_WAITQ))
                        return -EAGAIN;
                err = filemap_create_folio(filp, mapping,
-                               iocb->ki_pos >> PAGE_SHIFT, pvec);
+                               iocb->ki_pos >> PAGE_SHIFT, fbatch);
                if (err == AOP_TRUNCATED_PAGE)
                        goto retry;
                return err;
        }
 
-       folio = page_folio(pvec->pages[pagevec_count(pvec) - 1]);
+       folio = fbatch->folios[folio_batch_count(fbatch) - 1];
        if (folio_test_readahead(folio)) {
                err = filemap_readahead(iocb, filp, mapping, folio, last_index);
                if (err)
                        goto err;
        }
        if (!folio_test_uptodate(folio)) {
-               if ((iocb->ki_flags & IOCB_WAITQ) && pagevec_count(pvec) > 1)
+               if ((iocb->ki_flags & IOCB_WAITQ) &&
+                   folio_batch_count(fbatch) > 1)
                        iocb->ki_flags |= IOCB_NOWAIT;
                err = filemap_update_page(iocb, mapping, iter, folio);
                if (err)
@@ -2582,7 +2583,7 @@ retry:
 err:
        if (err < 0)
                folio_put(folio);
-       if (likely(--pvec->nr))
+       if (likely(--fbatch->nr))
                return 0;
        if (err == AOP_TRUNCATED_PAGE)
                goto retry;
@@ -2609,7 +2610,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
        struct file_ra_state *ra = &filp->f_ra;
        struct address_space *mapping = filp->f_mapping;
        struct inode *inode = mapping->host;
-       struct pagevec pvec;
+       struct folio_batch fbatch;
        int i, error = 0;
        bool writably_mapped;
        loff_t isize, end_offset;
@@ -2620,7 +2621,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
                return 0;
 
        iov_iter_truncate(iter, inode->i_sb->s_maxbytes);
-       pagevec_init(&pvec);
+       folio_batch_init(&fbatch);
 
        do {
                cond_resched();
@@ -2636,7 +2637,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
                if (unlikely(iocb->ki_pos >= i_size_read(inode)))
                        break;
 
-               error = filemap_get_pages(iocb, iter, &pvec);
+               error = filemap_get_pages(iocb, iter, &fbatch);
                if (error < 0)
                        break;
 
@@ -2650,7 +2651,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
                 */
                isize = i_size_read(inode);
                if (unlikely(iocb->ki_pos >= isize))
-                       goto put_pages;
+                       goto put_folios;
                end_offset = min_t(loff_t, isize, iocb->ki_pos + iter->count);
 
                /*
@@ -2665,10 +2666,10 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
                 */
                if (iocb->ki_pos >> PAGE_SHIFT !=
                    ra->prev_pos >> PAGE_SHIFT)
-                       mark_page_accessed(pvec.pages[0]);
+                       folio_mark_accessed(fbatch.folios[0]);
 
-               for (i = 0; i < pagevec_count(&pvec); i++) {
-                       struct folio *folio = page_folio(pvec.pages[i]);
+               for (i = 0; i < folio_batch_count(&fbatch); i++) {
+                       struct folio *folio = fbatch.folios[i];
                        size_t fsize = folio_size(folio);
                        size_t offset = iocb->ki_pos & (fsize - 1);
                        size_t bytes = min_t(loff_t, end_offset - iocb->ki_pos,
@@ -2698,10 +2699,10 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
                                break;
                        }
                }
-put_pages:
-               for (i = 0; i < pagevec_count(&pvec); i++)
-                       put_page(pvec.pages[i]);
-               pagevec_reinit(&pvec);
+put_folios:
+               for (i = 0; i < folio_batch_count(&fbatch); i++)
+                       folio_put(fbatch.folios[i]);
+               folio_batch_init(&fbatch);
        } while (iov_iter_count(iter) && iocb->ki_pos < isize && !error);
 
        file_accessed(filp);