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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: Yu Kuai <yukuai3@huawei.com>,
	hch@infradead.org, darrick.wong@oracle.com, david@fromorbit.com,
	linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, yi.zhang@huawei.com
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: [PATCH 3/3] iomap: Support arbitrarily many blocks per page
Date: Fri, 21 Aug 2020 13:46:06 +0100	[thread overview]
Message-ID: <20200821124606.10165-3-willy@infradead.org> (raw)
In-Reply-To: <20200821124606.10165-1-willy@infradead.org>

Size the uptodate array dynamically and add a few debugging assertions.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/iomap/buffered-io.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index dbf9572dabe9..844e95cacea8 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -22,18 +22,19 @@
 #include "../internal.h"
 
 /*
- * Structure allocated for each page when block size < PAGE_SIZE to track
+ * Structure allocated for each page when block size < page size to track
  * sub-page uptodate status and I/O completions.
  */
 struct iomap_page {
 	atomic_t		read_count;
 	atomic_t		write_count;
 	spinlock_t		uptodate_lock;
-	DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
+	unsigned long		uptodate[];
 };
 
 static inline struct iomap_page *to_iomap_page(struct page *page)
 {
+	VM_BUG_ON_PGFLAGS(PageTail(page), page);
 	if (page_has_private(page))
 		return (struct iomap_page *)page_private(page);
 	return NULL;
@@ -45,11 +46,13 @@ static struct iomap_page *
 iomap_page_create(struct inode *inode, struct page *page)
 {
 	struct iomap_page *iop = to_iomap_page(page);
+	unsigned int nr_blocks = i_blocks_per_page(inode, page);
 
-	if (iop || i_blocks_per_page(inode, page) <= 1)
+	if (iop || nr_blocks <= 1)
 		return iop;
 
-	iop = kzalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
+	iop = kzalloc(struct_size(iop, uptodate, BITS_TO_LONGS(nr_blocks)),
+			GFP_NOFS | __GFP_NOFAIL);
 	spin_lock_init(&iop->uptodate_lock);
 	attach_page_private(page, iop);
 	return iop;
@@ -59,11 +62,14 @@ static void
 iomap_page_release(struct page *page)
 {
 	struct iomap_page *iop = detach_page_private(page);
+	unsigned int nr_blocks = i_blocks_per_page(page->mapping->host, page);
 
 	if (!iop)
 		return;
 	WARN_ON_ONCE(atomic_read(&iop->read_count));
 	WARN_ON_ONCE(atomic_read(&iop->write_count));
+	WARN_ON_ONCE(bitmap_full(iop->uptodate, nr_blocks) !=
+			PageUptodate(page));
 	kfree(iop);
 }
 
-- 
2.28.0


  parent reply	other threads:[~2020-08-21 12:46 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21 12:33 [RFC PATCH V4] iomap: add support to track dirty state of sub pages Yu Kuai
2020-08-21 12:44 ` Matthew Wilcox
2020-08-21 12:46   ` [PATCH 1/3] iomap: Use kzalloc to allocate iomap_page Matthew Wilcox (Oracle)
2020-08-21 12:46     ` [PATCH 2/3] iomap: Use bitmap ops to set uptodate bits Matthew Wilcox (Oracle)
2020-08-22  5:59       ` Christoph Hellwig
2020-08-21 12:46     ` Matthew Wilcox (Oracle) [this message]
2020-08-21 12:48       ` [PATCH 3/3] iomap: Support arbitrarily many blocks per page Matthew Wilcox
2020-08-22  6:01       ` Christoph Hellwig
2020-08-22  5:57     ` [PATCH 1/3] iomap: Use kzalloc to allocate iomap_page Christoph Hellwig
2020-09-11  8:27   ` [RFC PATCH V4] iomap: add support to track dirty state of sub pages yukuai (C)
2020-09-11  8:35     ` yukuai (C)
2020-09-11 12:05     ` Matthew Wilcox
2020-09-25  2:30       ` yukuai (C)

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