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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 15/18] mm/filemap: Restructure filemap_get_pages
Date: Thu, 21 Jan 2021 04:16:13 +0000	[thread overview]
Message-ID: <20210121041616.3955703-16-willy@infradead.org> (raw)
In-Reply-To: <20210121041616.3955703-1-willy@infradead.org>

Remove the got_pages label, remove indentation, rename find_page to retry,
simplify error handling.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
---
 mm/filemap.c | 71 +++++++++++++++++++++-------------------------------
 1 file changed, 28 insertions(+), 43 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index f1c5c7d7aae8e..e09f0f1209a90 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2338,70 +2338,55 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
 	struct file_ra_state *ra = &filp->f_ra;
 	pgoff_t index = iocb->ki_pos >> PAGE_SHIFT;
 	pgoff_t last_index;
+	struct page *page;
 	int err = 0;
 
 	last_index = DIV_ROUND_UP(iocb->ki_pos + iter->count, PAGE_SIZE);
-find_page:
+retry:
 	if (fatal_signal_pending(current))
 		return -EINTR;
 
-	filemap_get_read_batch(mapping, index, last_index, pvec);
-	if (pvec->nr)
-		goto got_pages;
-
-	if (iocb->ki_flags & IOCB_NOIO)
-		return -EAGAIN;
-
-	page_cache_sync_readahead(mapping, ra, filp, index, last_index - index);
-
 	filemap_get_read_batch(mapping, index, last_index, pvec);
+	if (!pagevec_count(pvec)) {
+		if (iocb->ki_flags & IOCB_NOIO)
+			return -EAGAIN;
+		page_cache_sync_readahead(mapping, ra, filp, index,
+				last_index - index);
+		filemap_get_read_batch(mapping, index, last_index, pvec);
+	}
 	if (!pagevec_count(pvec)) {
 		if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_WAITQ))
 			return -EAGAIN;
 		err = filemap_create_page(filp, mapping,
 				iocb->ki_pos >> PAGE_SHIFT, pvec);
 		if (err == AOP_TRUNCATED_PAGE)
-			goto find_page;
+			goto retry;
 		return err;
 	}
-got_pages:
-	{
-		struct page *page = pvec->pages[pvec->nr - 1];
-
-		if (PageReadahead(page)) {
-			err = filemap_readahead(iocb, filp, mapping, page,
-					last_index);
-			if (err) {
-				put_page(page);
-				pvec->nr--;
-				goto err;
-			}
-		}
 
-		if (!PageUptodate(page)) {
-			if ((iocb->ki_flags & IOCB_WAITQ) &&
-			    pagevec_count(pvec) > 1)
-				iocb->ki_flags |= IOCB_NOWAIT;
-			err = filemap_update_page(iocb, mapping, iter, page);
-			if (err) {
-				if (err < 0)
-					put_page(page);
-				pvec->nr--;
-			}
-		}
+	page = pvec->pages[pagevec_count(pvec) - 1];
+	if (PageReadahead(page)) {
+		err = filemap_readahead(iocb, filp, mapping, page, last_index);
+		if (err)
+			goto err;
+	}
+	if (!PageUptodate(page)) {
+		if ((iocb->ki_flags & IOCB_WAITQ) && pagevec_count(pvec) > 1)
+			iocb->ki_flags |= IOCB_NOWAIT;
+		err = filemap_update_page(iocb, mapping, iter, page);
+		if (err)
+			goto err;
 	}
 
+	return 0;
 err:
-	if (likely(pvec->nr))
+	if (err < 0)
+		put_page(page);
+	if (likely(--pvec->nr))
 		return 0;
 	if (err == AOP_TRUNCATED_PAGE)
-		goto find_page;
-	if (err)
-		return err;
-	/*
-	 * No pages and no error means we raced and should retry:
-	 */
-	goto find_page;
+		goto retry;
+	return err;
 }
 
 /**
-- 
2.29.2


  parent reply	other threads:[~2021-01-21  4:32 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 ` [PATCH v4 12/18] mm/filemap: Move the iocb checks into filemap_update_page Matthew Wilcox (Oracle)
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 ` Matthew Wilcox (Oracle) [this message]
2021-01-21  7:33   ` [PATCH v4 15/18] mm/filemap: Restructure filemap_get_pages 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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