Move the complicated condition and the calculations out of
filemap_update_page() into its own function.
---
mm/filemap.c | 49 +++++++++++++++++++++++++++++++++----------------
1 file changed, 33 insertions(+), 16 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 41b90243f4ee..81b569d818a3 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2228,11 +2228,39 @@ static int filemap_read_page(struct file *file, struct address_space *mapping,
return error;
}
+static bool filemap_range_uptodate(struct kiocb *iocb,
+ struct address_space *mapping, struct iov_iter *iter,
+ struct page *page)
+{
+ loff_t pos;
+ int count;
+
+ if (PageUptodate(page))
+ return true;
+ /* pipes can't handle partially uptodate pages */
+ if (iov_iter_is_pipe(iter))
+ return false;
+ if (!mapping->a_ops->is_partially_uptodate)
+ return false;
+ if (mapping->host->i_blkbits >= (PAGE_SHIFT + thp_order(page)))
+ return false;
+
+ pos = (loff_t) page->index << PAGE_SHIFT;
+ if (pos > iocb->ki_pos) {
+ count = iocb->ki_pos + iter->count - pos;
+ pos = 0;
+ } else {
+ count = iter->count;
+ pos = iocb->ki_pos & (thp_size(page) - 1);
+ }
+
+ return mapping->a_ops->is_partially_uptodate(page, pos, count);
+}
+
static int filemap_update_page(struct kiocb *iocb,
struct address_space *mapping, struct iov_iter *iter,
struct page *page, loff_t pos, loff_t count, bool first)
{
- struct inode *inode = mapping->host;
int error = -EAGAIN;
if (!trylock_page(page)) {
@@ -2252,22 +2280,11 @@ static int filemap_update_page(struct kiocb *iocb,
if (!page->mapping)
goto truncated;
- if (PageUptodate(page))
- goto uptodate;
- if (inode->i_blkbits == PAGE_SHIFT ||
- !mapping->a_ops->is_partially_uptodate)
- goto readpage;
- /* pipes can't handle partially uptodate pages */
- if (unlikely(iov_iter_is_pipe(iter)))
- goto readpage;
- if (!mapping->a_ops->is_partially_uptodate(page,
- pos & (thp_size(page) - 1), count))
- goto readpage;
-uptodate:
- unlock_page(page);
- return 0;
+ if (filemap_range_uptodate(iocb, mapping, iter, page)) {
+ unlock_page(page);
+ return 0;
+ }
-readpage:
if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) {
unlock_page(page);
error = -EAGAIN;
--
2.28.0
