From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/filemap.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) --- a/mm/filemap.c~mm-filemap-use-filemap_read_page-in-filemap_fault +++ a/mm/filemap.c @@ -2980,7 +2980,6 @@ vm_fault_t filemap_fault(struct vm_fault 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 @@ page_not_uptodate: * 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 @@ page_not_uptodate: if (!error || error == AOP_TRUNCATED_PAGE) goto retry_find; - shrink_readahead_size_eio(ra); return VM_FAULT_SIGBUS; out_retry: _
