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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-mm@kvack.org, linux-block@vger.kernel.org
Subject: [PATCH v15 01/17] block: Add bio_add_folio()
Date: Mon, 19 Jul 2021 19:39:45 +0100	[thread overview]
Message-ID: <20210719184001.1750630-2-willy@infradead.org> (raw)
In-Reply-To: <20210719184001.1750630-1-willy@infradead.org>

This is a thin wrapper around bio_add_page().  The main advantage here
is the documentation that the submitter can expect to see folios in the
completion handler, and that stupidly large folios are not supported.
It's not currently possible to allocate stupidly large folios, but if
it ever becomes possible, this function will fail gracefully instead of
doing I/O to the wrong bytes.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 block/bio.c         | 21 +++++++++++++++++++++
 include/linux/bio.h |  3 ++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index 1fab762e079b..c64e35548fb2 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -933,6 +933,27 @@ int bio_add_page(struct bio *bio, struct page *page,
 }
 EXPORT_SYMBOL(bio_add_page);
 
+/**
+ * bio_add_folio - Attempt to add part of a folio to a bio.
+ * @bio: Bio to add to.
+ * @folio: Folio to add.
+ * @len: How many bytes from the folio to add.
+ * @off: First byte in this folio to add.
+ *
+ * Always uses the head page of the folio in the bio.  If a submitter only
+ * uses bio_add_folio(), it can count on never seeing tail pages in the
+ * completion routine.  BIOs do not support folios that are 4GiB or larger.
+ *
+ * Return: The number of bytes from this folio added to the bio.
+ */
+size_t bio_add_folio(struct bio *bio, struct folio *folio, size_t len,
+		size_t off)
+{
+	if (len > UINT_MAX || off > UINT_MAX)
+		return 0;
+	return bio_add_page(bio, &folio->page, len, off);
+}
+
 void bio_release_pages(struct bio *bio, bool mark_dirty)
 {
 	struct bvec_iter_all iter_all;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 2203b686e1f0..ade93e2de6a1 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -462,7 +462,8 @@ extern void bio_uninit(struct bio *);
 extern void bio_reset(struct bio *);
 void bio_chain(struct bio *, struct bio *);
 
-extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
+int bio_add_page(struct bio *, struct page *, unsigned len, unsigned off);
+size_t bio_add_folio(struct bio *, struct folio *, size_t len, size_t off);
 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 			   unsigned int, unsigned int);
 int bio_add_zone_append_page(struct bio *bio, struct page *page,
-- 
2.30.2


  reply	other threads:[~2021-07-19 22:08 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-19 18:39 [PATCH v15 00/17] Folio support in block + iomap layers Matthew Wilcox (Oracle)
2021-07-19 18:39 ` Matthew Wilcox (Oracle) [this message]
2021-07-20  1:28   ` [PATCH v15 01/17] block: Add bio_add_folio() Darrick J. Wong
2021-07-20  6:42   ` Christoph Hellwig
2021-07-20 11:16     ` Matthew Wilcox
2021-07-22 16:27     ` Matthew Wilcox
2021-07-30  8:25   ` Ming Lei
2021-07-30 11:30     ` Matthew Wilcox
2021-07-19 18:39 ` [PATCH v15 02/17] block: Add bio_for_each_folio_all() Matthew Wilcox (Oracle)
2021-07-20  1:29   ` Darrick J. Wong
2021-07-20  1:59     ` Matthew Wilcox
2021-07-20  6:48   ` Christoph Hellwig
2021-07-23  2:40     ` Matthew Wilcox
2021-07-20 12:05   ` kernel test robot
2021-07-20 12:05   ` kernel test robot
2021-07-20 12:26   ` kernel test robot
2021-07-19 18:39 ` [PATCH v15 03/17] iomap: Convert to_iomap_page to take a folio Matthew Wilcox (Oracle)
2021-07-20  6:49   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 04/17] iomap: Convert iomap_page_create " Matthew Wilcox (Oracle)
2021-07-20  6:50   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 05/17] iomap: Convert iomap_page_release " Matthew Wilcox (Oracle)
2021-07-20  6:52   ` Christoph Hellwig
2021-07-20 11:29     ` Matthew Wilcox
2021-07-20 11:40       ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 06/17] iomap: Convert iomap_releasepage to use " Matthew Wilcox (Oracle)
2021-07-20  6:54   ` Christoph Hellwig
2021-07-20 23:56   ` Darrick J. Wong
2021-07-19 18:39 ` [PATCH v15 07/17] iomap: Convert iomap_invalidatepage " Matthew Wilcox (Oracle)
2021-07-20  6:55   ` Christoph Hellwig
2021-07-20 23:57   ` Darrick J. Wong
2021-07-19 18:39 ` [PATCH v15 08/17] iomap: Pass the iomap_page into iomap_set_range_uptodate Matthew Wilcox (Oracle)
2021-07-20  6:57   ` Christoph Hellwig
2021-07-20 11:36     ` Matthew Wilcox
2021-07-19 18:39 ` [PATCH v15 09/17] iomap: Use folio offsets instead of page offsets Matthew Wilcox (Oracle)
2021-07-20  6:59   ` Christoph Hellwig
2021-07-20 11:42     ` Matthew Wilcox
2021-07-19 18:39 ` [PATCH v15 10/17] iomap: Convert bio completions to use folios Matthew Wilcox (Oracle)
2021-07-20  7:08   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 11/17] iomap: Convert readahead and readpage to use a folio Matthew Wilcox (Oracle)
2021-07-20  7:09   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 12/17] iomap: Convert iomap_page_mkwrite " Matthew Wilcox (Oracle)
2021-07-20  7:13   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 13/17] iomap: Convert iomap_write_begin and iomap_write_end to folios Matthew Wilcox (Oracle)
2021-07-20  7:15   ` Christoph Hellwig
2021-07-20 23:59   ` Darrick J. Wong
2021-07-19 18:39 ` [PATCH v15 14/17] iomap: Convert iomap_read_inline_data to take a folio Matthew Wilcox (Oracle)
2021-07-20  7:16   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 15/17] iomap: Convert iomap_write_end_inline " Matthew Wilcox (Oracle)
2021-07-20  7:17   ` Christoph Hellwig
2021-07-19 18:40 ` [PATCH v15 16/17] iomap: Convert iomap_add_to_ioend " Matthew Wilcox (Oracle)
2021-07-20  7:20   ` Christoph Hellwig
2021-07-20 11:45     ` Matthew Wilcox
2021-07-21  0:12   ` Darrick J. Wong
2021-07-21  4:27     ` Christoph Hellwig
2021-07-21  4:31       ` Matthew Wilcox
2021-07-21 15:28         ` Darrick J. Wong
2021-07-19 18:40 ` [PATCH v15 17/17] iomap: Convert iomap_migrate_page to use folios Matthew Wilcox (Oracle)
2021-07-20  7:21   ` Christoph Hellwig
2021-07-20 13:30   ` kernel test robot
2021-07-21  0:02   ` Darrick J. Wong
2021-07-20  8:44 ` [PATCH v15 00/17] Folio support in block + iomap layers Christoph Hellwig
2021-07-20 11:08   ` Matthew Wilcox

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