[PATCH 1/2] fs: Remove calls to set and clear the folio error flag

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

Nobody checks the folio error flag any more, so we can stop setting
and clearing it.  Also remove the documentation suggesting to not
bother setting the error bit.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 Documentation/filesystems/vfs.rst | 3 +--
 mm/filemap.c                      | 8 --------
 mm/migrate.c                      | 2 --
 mm/page_io.c                      | 4 +---
 4 files changed, 2 insertions(+), 15 deletions(-)

diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
index 6e903a903f8f..a6022ec59a2d 100644
--- a/Documentation/filesystems/vfs.rst
+++ b/Documentation/filesystems/vfs.rst
@@ -913,8 +913,7 @@ cache in your filesystem.  The following members are defined:
 	stop attempting I/O, it can simply return.  The caller will
 	remove the remaining pages from the address space, unlock them
 	and decrement the page refcount.  Set PageUptodate if the I/O
-	completes successfully.  Setting PageError on any page will be
-	ignored; simply unlock the page if an I/O error occurs.
+	completes successfully.
 
 ``write_begin``
 	Called by the generic buffered write code to ask the filesystem
diff --git a/mm/filemap.c b/mm/filemap.c
index d62150418b91..c7bef2247a68 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -530,7 +530,6 @@ static void __filemap_fdatawait_range(struct address_space *mapping,
 			struct folio *folio = fbatch.folios[i];
 
 			folio_wait_writeback(folio);
-			folio_clear_error(folio);
 		}
 		folio_batch_release(&fbatch);
 		cond_resched();
@@ -2342,13 +2341,6 @@ static int filemap_read_folio(struct file *file, filler_t filler,
 	unsigned long pflags;
 	int error;
 
-	/*
-	 * A previous I/O error may have been due to temporary failures,
-	 * eg. multipath errors.  PG_error will be set again if read_folio
-	 * fails.
-	 */
-	folio_clear_error(folio);
-
 	/* Start the actual read. The read will unlock the page. */
 	if (unlikely(workingset))
 		psi_memstall_enter(&pflags);
diff --git a/mm/migrate.c b/mm/migrate.c
index e7296c0fb5d5..e4431c157bc9 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -585,8 +585,6 @@ void folio_migrate_flags(struct folio *newfolio, struct folio *folio)
 {
 	int cpupid;
 
-	if (folio_test_error(folio))
-		folio_set_error(newfolio);
 	if (folio_test_referenced(folio))
 		folio_set_referenced(newfolio);
 	if (folio_test_uptodate(folio))
diff --git a/mm/page_io.c b/mm/page_io.c
index ff8c99ee3af7..9d4edf8bc422 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -273,9 +273,7 @@ static void sio_write_complete(struct kiocb *iocb, long ret)
 		 * memory for allocating transmit buffers.
 		 * Mark the page dirty and avoid
 		 * folio_rotate_reclaimable but rate-limit the
-		 * messages but do not flag PageError like
-		 * the normal direct-to-bio case as it could
-		 * be temporary.
+		 * messages.
 		 */
 		pr_err_ratelimited("Write error %ld on dio swapfile (%llu)\n",
 				   ret, swap_dev_pos(page_swap_entry(page)));
-- 
2.43.0