From: Christian Brauner <brauner@kernel.org>
Date: Thu, 3 Feb 2022 13:14:07 +0000 (+0100)
Subject: fs: add kernel doc for mnt_{hold,unhold}_writers()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=538f4f022a4612f969d5324ee227403c9f8b1d72;p=linux.git

fs: add kernel doc for mnt_{hold,unhold}_writers()

When I introduced mnt_{hold,unhold}_writers() in commit fbdc2f6c40f6
("fs: split out functions to hold writers") I did not add kernel doc for
them. Fix this and introduce proper documentation.

Link: https://lore.kernel.org/r/20220203131411.3093040-4-brauner@kernel.org
Fixes: fbdc2f6c40f6 ("fs: split out functions to hold writers")
Cc: Seth Forshee <seth.forshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---

diff --git a/fs/namespace.c b/fs/namespace.c
index 40b994a29e90d..de6fae84f1a1a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -469,6 +469,24 @@ void mnt_drop_write_file(struct file *file)
 }
 EXPORT_SYMBOL(mnt_drop_write_file);
 
+/**
+ * mnt_hold_writers - prevent write access to the given mount
+ * @mnt: mnt to prevent write access to
+ *
+ * Prevents write access to @mnt if there are no active writers for @mnt.
+ * This function needs to be called and return successfully before changing
+ * properties of @mnt that need to remain stable for callers with write access
+ * to @mnt.
+ *
+ * After this functions has been called successfully callers must pair it with
+ * a call to mnt_unhold_writers() in order to stop preventing write access to
+ * @mnt.
+ *
+ * Context: This function expects lock_mount_hash() to be held serializing
+ *          setting MNT_WRITE_HOLD.
+ * Return: On success 0 is returned.
+ *	   On error, -EBUSY is returned.
+ */
 static inline int mnt_hold_writers(struct mount *mnt)
 {
 	mnt->mnt.mnt_flags |= MNT_WRITE_HOLD;
@@ -500,6 +518,18 @@ static inline int mnt_hold_writers(struct mount *mnt)
 	return 0;
 }
 
+/**
+ * mnt_unhold_writers - stop preventing write access to the given mount
+ * @mnt: mnt to stop preventing write access to
+ *
+ * Stop preventing write access to @mnt allowing callers to gain write access
+ * to @mnt again.
+ *
+ * This function can only be called after a successful call to
+ * mnt_hold_writers().
+ *
+ * Context: This function expects lock_mount_hash() to be held.
+ */
 static inline void mnt_unhold_writers(struct mount *mnt)
 {
 	/*