From fce70da3a80fcd0a9c0192dedd6bf86a43845ac9 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Wed, 24 Feb 2021 12:02:28 -0800 Subject: [PATCH] mm/filemap: add filemap_range_uptodate Move the complicated condition and the calculations out of filemap_update_page() into its own function. [willy@infradead.org: unlock page before dropping its refcount] Link: https://lkml.kernel.org/r/20210201125229.GO308988@casper.infradead.org Link: https://lkml.kernel.org/r/20210122160140.223228-14-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Kent Overstreet Reviewed-by: Christoph Hellwig Cc: Miaohe Lin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 65 ++++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 39 insertions(+), 26 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index cd863c4ff9ae..1eaafc9402e0 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2233,11 +2233,36 @@ static int filemap_read_page(struct file *file, struct address_space *mapping, return error; } +static bool filemap_range_uptodate(struct address_space *mapping, + loff_t pos, struct iov_iter *iter, struct page *page) +{ + 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; + + count = iter->count; + if (page_offset(page) > pos) { + count -= page_offset(page) - pos; + pos = 0; + } else { + pos -= page_offset(page); + } + + 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) + struct page *page) { - struct inode *inode = mapping->host; int error; if (!trylock_page(page)) { @@ -2254,26 +2279,15 @@ 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; -readpage: - if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) { - unlock_page(page); - return -EAGAIN; - } + error = 0; + if (filemap_range_uptodate(mapping, iocb->ki_pos, iter, page)) + goto unlock; + + error = -EAGAIN; + if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) + goto unlock; + error = filemap_read_page(iocb->ki_filp, mapping, page); if (error == AOP_TRUNCATED_PAGE) put_page(page); @@ -2282,6 +2296,9 @@ truncated: unlock_page(page); put_page(page); return AOP_TRUNCATED_PAGE; +unlock: + unlock_page(page); + return error; } static int filemap_create_page(struct file *file, @@ -2351,9 +2368,6 @@ got_pages: { struct page *page = pvec->pages[pvec->nr - 1]; pgoff_t pg_index = page->index; - loff_t pg_pos = max(iocb->ki_pos, - (loff_t) pg_index << PAGE_SHIFT); - loff_t pg_count = iocb->ki_pos + iter->count - pg_pos; if (PageReadahead(page)) { if (iocb->ki_flags & IOCB_NOIO) { @@ -2370,8 +2384,7 @@ got_pages: if ((iocb->ki_flags & IOCB_WAITQ) && pagevec_count(pvec) > 1) iocb->ki_flags |= IOCB_NOWAIT; - err = filemap_update_page(iocb, mapping, iter, page, - pg_pos, pg_count); + err = filemap_update_page(iocb, mapping, iter, page); if (err) { if (err < 0) put_page(page); -- 2.11.0