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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-doc@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 5/8] buffer: Add kernel-doc for brelse() and __brelse()
Date: Tue,  9 Jan 2024 14:33:54 +0000
Message-Id: <20240109143357.2375046-6-willy@infradead.org>
In-Reply-To: <20240109143357.2375046-1-willy@infradead.org>
References: <20240109143357.2375046-1-willy@infradead.org>
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Move the documentation for __brelse() to brelse(), format it as
kernel-doc and update it from talking about pages to folios.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/buffer.c                 | 17 ++++++++---------
 include/linux/buffer_head.h | 16 ++++++++++++++++
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 160bbc1f929c..9a7b3649c872 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1226,17 +1226,16 @@ void mark_buffer_write_io_error(struct buffer_head *bh)
 }
 EXPORT_SYMBOL(mark_buffer_write_io_error);
 
-/*
- * Decrement a buffer_head's reference count.  If all buffers against a page
- * have zero reference count, are clean and unlocked, and if the page is clean
- * and unlocked then try_to_free_buffers() may strip the buffers from the page
- * in preparation for freeing it (sometimes, rarely, buffers are removed from
- * a page but it ends up not being freed, and buffers may later be reattached).
+/**
+ * __brelse - Release a buffer.
+ * @bh: The buffer to release.
+ *
+ * This variant of brelse() can be called if @bh is guaranteed to not be NULL.
  */
-void __brelse(struct buffer_head * buf)
+void __brelse(struct buffer_head *bh)
 {
-	if (atomic_read(&buf->b_count)) {
-		put_bh(buf);
+	if (atomic_read(&bh->b_count)) {
+		put_bh(bh);
 		return;
 	}
 	WARN(1, KERN_ERR "VFS: brelse: Trying to free free buffer\n");
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 56a1e9c1e71e..3cbc01bbc398 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -303,6 +303,22 @@ static inline void put_bh(struct buffer_head *bh)
         atomic_dec(&bh->b_count);
 }
 
+/**
+ * brelse - Release a buffer.
+ * @bh: The buffer to release.
+ *
+ * Decrement a buffer_head's reference count.  If @bh is NULL, this
+ * function is a no-op.
+ *
+ * If all buffers on a folio have zero reference count, are clean
+ * and unlocked, and if the folio is clean and unlocked then
+ * try_to_free_buffers() may strip the buffers from the folio in
+ * preparation for freeing it (sometimes, rarely, buffers are removed
+ * from a folio but it ends up not being freed, and buffers may later
+ * be reattached).
+ *
+ * Context: Any context.
+ */
 static inline void brelse(struct buffer_head *bh)
 {
 	if (bh)
-- 
2.43.0