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From:   "wangjianjian (C)" <wangjianjian3@huawei.com>
To:     "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        "Darrick J. Wong" <djwong@kernel.org>
CC:     "linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        Jens Axboe <axboe@kernel.dk>,
        Christoph Hellwig <hch@infradead.org>
Subject: RE: [PATCH 02/21] block: Add bio_add_folio()
Thread-Topic: [PATCH 02/21] block: Add bio_add_folio()
Thread-Index: AQHXz2GCGZfotygsu0GMr7Q1z+eru6vxBCEA
Date:   Wed, 3 Nov 2021 01:25:57 +0000
Message-ID: <d1d037a13796462a968b5de97c459ecc@huawei.com>
References: <20211101203929.954622-1-willy@infradead.org>
 <20211101203929.954622-3-willy@infradead.org>
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diff --git a/block/bio.c b/block/bio.c
index 15ab0d6d1c06..0e911c4fb9f2 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1033,6 +1033,28 @@ 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.
+ *
+ * Filesystems that use folios can call this function instead of 
+calling
+ * bio_add_page() for each page in the folio.  If @off is bigger than
+ * PAGE_SIZE, this function can create a bio_vec that starts in a page
+ * after the bv_page.  BIOs do not support folios that are 4GiB or larger.
+ *
+ * Return: Whether the addition was successful.
+ */
+bool 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) > 0; }
+


Newline.