Commit d31fa86a authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm/filemap: use filemap_read_page in filemap_fault 

After splitting generic_file_buffered_read() into smaller parts, it turns
out we can reuse one of the parts in filemap_fault().  This fixes an
oversight -- waiting for the I/O to complete is now interruptible by a
fatal signal.  And it saves us a few bytes of text in an unlikely path.

  $ ./scripts/bloat-o-meter before.o after.o
  add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-207 (-207)
  Function                                     old     new   delta
  filemap_fault                               2187    1980    -207
  Total: Before=37491, After=37284, chg -0.55%

Link: https://lkml.kernel.org/r/20210226140011.2883498-1-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 985b71db

mm/filemap.c

+1 −9
Original line number Diff line number Diff line
@@ -2980,7 +2980,6 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) 
	struct file *file = vmf->vma->vm_file;

	struct file *fpin = NULL;

	struct address_space *mapping = file->f_mapping;

	struct file_ra_state *ra = &file->f_ra;

	struct inode *inode = mapping->host;

	pgoff_t offset = vmf->pgoff;

	pgoff_t max_off;
@@ -3067,14 +3066,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) 
	 * because there really aren't any performance issues here

	 * and we need to check for errors.

	 */

	ClearPageError(page);

	fpin = maybe_unlock_mmap_for_io(vmf, fpin);

	error = mapping->a_ops->readpage(file, page);

	if (!error) {

		wait_on_page_locked(page);

		if (!PageUptodate(page))

			error = -EIO;

	}

	error = filemap_read_page(file, mapping, page);

	if (fpin)

		goto out_retry;

	put_page(page);
@@ -3082,7 +3075,6 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) 
	if (!error || error == AOP_TRUNCATED_PAGE)

		goto retry_find;



	shrink_readahead_size_eio(ra);

	return VM_FAULT_SIGBUS;



out_retry: