linux-kernel - [PATCH v6 29/99] page cache: Convert filemap_range_has

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Date:   Wed, 17 Jan 2018 12:20:53 -0800
From:   Matthew Wilcox <willy@...radead.org>
To:     linux-kernel@...r.kernel.org
Cc:     Matthew Wilcox <mawilcox@...rosoft.com>, linux-mm@...ck.org,
        linux-fsdevel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-nilfs@...r.kernel.org, linux-btrfs@...r.kernel.org,
        linux-xfs@...r.kernel.org, linux-usb@...r.kernel.org,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Stefano Stabellini <sstabellini@...nel.org>,
        iommu@...ts.linux-foundation.org, linux-remoteproc@...r.kernel.org,
        linux-s390@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
        cgroups@...r.kernel.org, linux-sh@...r.kernel.org,
        David Howells <dhowells@...hat.com>
Subject: [PATCH v6 29/99] page cache: Convert filemap_range_has_page to XArray

From: Matthew Wilcox <mawilcox@...rosoft.com>

Instead of calling find_get_pages_range() and putting any reference,
just use xa_find() to look for a page in the right range.

Signed-off-by: Matthew Wilcox <mawilcox@...rosoft.com>
---
 mm/filemap.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 2536fcacb5bc..cd01f353cf6a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -461,18 +461,11 @@ bool filemap_range_has_page(struct address_space *mapping,
 {
 	pgoff_t index = start_byte >> PAGE_SHIFT;
 	pgoff_t end = end_byte >> PAGE_SHIFT;
-	struct page *page;
 
 	if (end_byte < start_byte)
 		return false;
 
-	if (mapping->nrpages == 0)
-		return false;
-
-	if (!find_get_pages_range(mapping, &index, end, 1, &page))
-		return false;
-	put_page(page);
-	return true;
+	return xa_find(&mapping->pages, &index, end, XA_PRESENT);
 }
 EXPORT_SYMBOL(filemap_range_has_page);
 
-- 
2.15.1