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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	hch@lst.de, kent.overstreet@gmail.com
Subject: [PATCH v4 12/18] mm/filemap: Move the iocb checks into filemap_update_page
Date: Thu, 21 Jan 2021 04:16:10 +0000	[thread overview]
Message-ID: <20210121041616.3955703-13-willy@infradead.org> (raw)
In-Reply-To: <20210121041616.3955703-1-willy@infradead.org>

We don't need to give up when a non-blocking request sees a !Uptodate page.
We may be able to satisfy the read from a partially-uptodate page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 mm/filemap.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index adac12ed48415..141d5917770d6 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2230,15 +2230,16 @@ static int filemap_update_page(struct kiocb *iocb,
 	struct inode *inode = mapping->host;
 	int error;
 
-	if (iocb->ki_flags & IOCB_WAITQ) {
-		error = lock_page_async(page, iocb->ki_waitq);
-		if (error)
-			return error;
-	} else {
-		if (!trylock_page(page)) {
+	if (!trylock_page(page)) {
+		if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_NOIO))
+			return -EAGAIN;
+		if (!(iocb->ki_flags & IOCB_WAITQ)) {
 			put_and_wait_on_page_locked(page, TASK_KILLABLE);
 			return AOP_TRUNCATED_PAGE;
 		}
+		error = __lock_page_async(page, iocb->ki_waitq);
+		if (error)
+			return error;
 	}
 
 	if (!page->mapping)
@@ -2356,14 +2357,9 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
 		}
 
 		if (!PageUptodate(page)) {
-			if ((iocb->ki_flags & IOCB_NOWAIT) ||
-			    ((iocb->ki_flags & IOCB_WAITQ) && pvec->nr > 1)) {
-				put_page(page);
-				pvec->nr--;
-				err = -EAGAIN;
-				goto err;
-			}
-
+			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);
 			if (err) {
-- 
2.29.2



  parent reply	other threads:[~2021-01-21  4:27 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-21  4:15 [PATCH v4 00/18] Refactor generic_file_buffered_read Matthew Wilcox (Oracle)
2021-01-21  4:15 ` [PATCH v4 01/18] mm/filemap: Rename generic_file_buffered_read subfunctions Matthew Wilcox (Oracle)
2021-01-21  7:30   ` Christoph Hellwig
2021-01-21  8:23   ` Miaohe Lin
2021-01-21  4:16 ` [PATCH v4 02/18] mm/filemap: Remove dynamically allocated array from filemap_read Matthew Wilcox (Oracle)
2021-01-21  7:31   ` Christoph Hellwig
2021-01-22  6:59   ` Miaohe Lin
2021-01-21  4:16 ` [PATCH v4 03/18] mm/filemap: Convert filemap_get_pages to take a pagevec Matthew Wilcox (Oracle)
2021-01-21  7:31   ` Christoph Hellwig
2021-01-21  4:16 ` [PATCH v4 04/18] mm/filemap: Use head pages in generic_file_buffered_read Matthew Wilcox (Oracle)
2021-01-21  4:16 ` [PATCH v4 05/18] mm/filemap: Pass a sleep state to put_and_wait_on_page_locked Matthew Wilcox (Oracle)
2021-01-21  4:16 ` [PATCH v4 06/18] mm/filemap: Support readpage splitting a page Matthew Wilcox (Oracle)
2021-01-21  4:16 ` [PATCH v4 07/18] mm/filemap: Inline __wait_on_page_locked_async into caller Matthew Wilcox (Oracle)
2021-01-21  4:16 ` [PATCH v4 08/18] mm/filemap: Don't call ->readpage if IOCB_WAITQ is set Matthew Wilcox (Oracle)
2021-01-21  4:16 ` [PATCH v4 09/18] mm/filemap: Change filemap_read_page calling conventions Matthew Wilcox (Oracle)
2021-01-21  7:31   ` Christoph Hellwig
2021-01-21  4:16 ` [PATCH v4 10/18] mm/filemap: Change filemap_create_page " Matthew Wilcox (Oracle)
2021-01-21  4:16 ` [PATCH v4 11/18] mm/filemap: Convert filemap_update_page to return an errno Matthew Wilcox (Oracle)
2021-01-21  7:32   ` Christoph Hellwig
2021-01-21  4:16 ` Matthew Wilcox (Oracle) [this message]
2021-01-21  4:16 ` [PATCH v4 13/18] mm/filemap: Add filemap_range_uptodate Matthew Wilcox (Oracle)
2021-01-21  7:32   ` Christoph Hellwig
2021-01-21  4:16 ` [PATCH v4 14/18] mm/filemap: Split filemap_readahead out of filemap_get_pages Matthew Wilcox (Oracle)
2021-01-21  7:33   ` Christoph Hellwig
2021-01-21  4:16 ` [PATCH v4 15/18] mm/filemap: Restructure filemap_get_pages Matthew Wilcox (Oracle)
2021-01-21  7:33   ` Christoph Hellwig
2021-01-21  4:16 ` [PATCH v4 16/18] mm/filemap: Don't relock the page after calling readpage Matthew Wilcox (Oracle)
2021-01-21  7:34   ` Christoph Hellwig
2021-01-21  4:16 ` [PATCH v4 17/18] mm/filemap: Rename generic_file_buffered_read to filemap_read Matthew Wilcox (Oracle)
2021-01-21  4:16 ` [PATCH v4 18/18] mm/filemap: Simplify generic_file_read_iter Matthew Wilcox (Oracle)

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