summaryrefslogtreecommitdiff
path: root/mm/page-writeback.c
diff options
context:
space:
mode:
authorMatthew Wilcox (Oracle) <willy@infradead.org>2024-02-15 07:36:44 +0100
committerAndrew Morton <akpm@linux-foundation.org>2024-02-23 17:48:36 -0800
commit807d1fe36077decf6f4ef8d4b63a084760a5c5fc (patch)
treeaada37024a42396ccefb080eb0d7c6a4efc1e00a /mm/page-writeback.c
parent751e0d559c62a87dc828af22c3c58dc078c734e3 (diff)
writeback: simplify the loops in write_cache_pages()
Collapse the two nested loops into one. This is needed as a step towards turning this into an iterator. Note that this drops the "index <= end" check in the previous outer loop and just relies on filemap_get_folios_tag() to return 0 entries when index > end. This actually has a subtle implication when end == -1 because then the returned index will be -1 as well and thus if there is page present on index -1, we could be looping indefinitely. But as the comment in filemap_get_folios_tag documents this as already broken anyway we should not worry about it here either. The fix for that would probably a change to the filemap_get_folios_tag() calling convention. [hch@lst.de: update the commit log per Jan] Link: https://lkml.kernel.org/r/20240215063649.2164017-10-hch@lst.de Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Dave Chinner <dchinner@redhat.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r--mm/page-writeback.c75
1 files changed, 36 insertions, 39 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 5b8dbbef7137..358ce3ade9ad 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2454,6 +2454,7 @@ int write_cache_pages(struct address_space *mapping,
int error;
struct folio *folio;
pgoff_t end; /* Inclusive */
+ int i = 0;
if (wbc->range_cyclic) {
wbc->index = mapping->writeback_index; /* prev offset */
@@ -2467,53 +2468,49 @@ int write_cache_pages(struct address_space *mapping,
folio_batch_init(&wbc->fbatch);
- while (wbc->index <= end) {
- int i;
-
- writeback_get_batch(mapping, wbc);
-
+ for (;;) {
+ if (i == wbc->fbatch.nr) {
+ writeback_get_batch(mapping, wbc);
+ i = 0;
+ }
if (wbc->fbatch.nr == 0)
break;
- for (i = 0; i < wbc->fbatch.nr; i++) {
- folio = wbc->fbatch.folios[i];
+ folio = wbc->fbatch.folios[i++];
- folio_lock(folio);
- if (!folio_prepare_writeback(mapping, wbc, folio)) {
- folio_unlock(folio);
- continue;
- }
+ folio_lock(folio);
+ if (!folio_prepare_writeback(mapping, wbc, folio)) {
+ folio_unlock(folio);
+ continue;
+ }
- trace_wbc_writepage(wbc, inode_to_bdi(mapping->host));
+ trace_wbc_writepage(wbc, inode_to_bdi(mapping->host));
- error = writepage(folio, wbc, data);
- wbc->nr_to_write -= folio_nr_pages(folio);
+ error = writepage(folio, wbc, data);
+ wbc->nr_to_write -= folio_nr_pages(folio);
- if (error == AOP_WRITEPAGE_ACTIVATE) {
- folio_unlock(folio);
- error = 0;
- }
+ if (error == AOP_WRITEPAGE_ACTIVATE) {
+ folio_unlock(folio);
+ error = 0;
+ }
- /*
- * For integrity writeback we have to keep going until
- * we have written all the folios we tagged for
- * writeback above, even if we run past wbc->nr_to_write
- * or encounter errors.
- * We stash away the first error we encounter in
- * wbc->saved_err so that it can be retrieved when we're
- * done. This is because the file system may still have
- * state to clear for each folio.
- *
- * For background writeback we exit as soon as we run
- * past wbc->nr_to_write or encounter the first error.
- */
- if (wbc->sync_mode == WB_SYNC_ALL) {
- if (error && !ret)
- ret = error;
- } else {
- if (error || wbc->nr_to_write <= 0)
- goto done;
- }
+ /*
+ * For integrity writeback we have to keep going until we have
+ * written all the folios we tagged for writeback above, even if
+ * we run past wbc->nr_to_write or encounter errors.
+ * We stash away the first error we encounter in wbc->saved_err
+ * so that it can be retrieved when we're done. This is because
+ * the file system may still have state to clear for each folio.
+ *
+ * For background writeback we exit as soon as we run past
+ * wbc->nr_to_write or encounter the first error.
+ */
+ if (wbc->sync_mode == WB_SYNC_ALL) {
+ if (error && !ret)
+ ret = error;
+ } else {
+ if (error || wbc->nr_to_write <= 0)
+ goto done;
}
}