diff mbox series

[30/48] filemap: Use a folio in filemap_page_mkwrite

Message ID 20211208042256.1923824-31-willy@infradead.org (mailing list archive)
State New, archived
Headers show
Series Folios for 5.17 | expand

Commit Message

Matthew Wilcox Dec. 8, 2021, 4:22 a.m. UTC 
This fixes a bug for tail pages.  They always have a NULL mapping, so
the check would fail and we would never mark the folio as dirty.
Ends up growing the kernel by 19 bytes although there will be fewer
calls to compound_head() dynamically.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/filemap.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Comments

Christoph Hellwig Dec. 23, 2021, 8:21 a.m. UTC | #1 
On Wed, Dec 08, 2021 at 04:22:38AM +0000, Matthew Wilcox (Oracle) wrote:
> This fixes a bug for tail pages.  They always have a NULL mapping, so
> the check would fail and we would never mark the folio as dirty.
> Ends up growing the kernel by 19 bytes although there will be fewer
> calls to compound_head() dynamically.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/mm/filemap.c b/mm/filemap.c
index 8cca04a79808..4ae9d5befffa 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3349,24 +3349,24 @@  EXPORT_SYMBOL(filemap_map_pages);
 vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf)
 {
 	struct address_space *mapping = vmf->vma->vm_file->f_mapping;
-	struct page *page = vmf->page;
+	struct folio *folio = page_folio(vmf->page);
 	vm_fault_t ret = VM_FAULT_LOCKED;
 
 	sb_start_pagefault(mapping->host->i_sb);
 	file_update_time(vmf->vma->vm_file);
-	lock_page(page);
-	if (page->mapping != mapping) {
-		unlock_page(page);
+	folio_lock(folio);
+	if (folio->mapping != mapping) {
+		folio_unlock(folio);
 		ret = VM_FAULT_NOPAGE;
 		goto out;
 	}
 	/*
-	 * We mark the page dirty already here so that when freeze is in
+	 * We mark the folio dirty already here so that when freeze is in
 	 * progress, we are guaranteed that writeback during freezing will
-	 * see the dirty page and writeprotect it again.
+	 * see the dirty folio and writeprotect it again.
 	 */
-	set_page_dirty(page);
-	wait_for_stable_page(page);
+	folio_mark_dirty(folio);
+	folio_wait_stable(folio);
 out:
 	sb_end_pagefault(mapping->host->i_sb);
 	return ret;