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From: Dave Chinner <david@fromorbit.com>
To: linux-fsdevel@vger.kernel.org
Cc: linux-block@vger.kernel.org, linux-cachefs@redhat.com,
	dhowells@redhat.com, gfs2@lists.linux.dev,
	dm-devel@lists.linux.dev, linux-security-module@vger.kernel.org,
	selinux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 07/11] hlist-bl: add hlist_bl_fake()
Date: Wed,  6 Dec 2023 17:05:36 +1100	[thread overview]
Message-ID: <20231206060629.2827226-8-david@fromorbit.com> (raw)
In-Reply-To: <20231206060629.2827226-1-david@fromorbit.com>

From: Dave Chinner <dchinner@redhat.com>

in preparation for switching the VFS inode cache over the hlist_bl
lists, we nee dto be able to fake a list node that looks like it is
hased for correct operation of filesystems that don't directly use
the VFS indoe cache.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 include/linux/list_bl.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h
index ae1b541446c9..8ee2bf5af131 100644
--- a/include/linux/list_bl.h
+++ b/include/linux/list_bl.h
@@ -143,6 +143,28 @@ static inline void hlist_bl_del_init(struct hlist_bl_node *n)
 	}
 }
 
+/**
+ * hlist_bl_add_fake - create a fake list consisting of a single headless node
+ * @n: Node to make a fake list out of
+ *
+ * This makes @n appear to be its own predecessor on a headless hlist.
+ * The point of this is to allow things like hlist_bl_del() to work correctly
+ * in cases where there is no list.
+ */
+static inline void hlist_bl_add_fake(struct hlist_bl_node *n)
+{
+	n->pprev = &n->next;
+}
+
+/**
+ * hlist_fake: Is this node a fake hlist_bl?
+ * @h: Node to check for being a self-referential fake hlist.
+ */
+static inline bool hlist_bl_fake(struct hlist_bl_node *n)
+{
+	return n->pprev == &n->next;
+}
+
 static inline void hlist_bl_lock(struct hlist_bl_head *b)
 {
 	bit_spin_lock(0, (unsigned long *)b);
-- 
2.42.0


  parent reply	other threads:[~2023-12-06  6:06 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-06  6:05 [PATCH 0/11] vfs: inode cache scalability improvements Dave Chinner
2023-12-06  6:05 ` [PATCH 01/11] lib/dlock-list: Distributed and lock-protected lists Dave Chinner
2023-12-07  2:23   ` Al Viro
2023-12-06  6:05 ` [PATCH 02/11] vfs: Remove unnecessary list_for_each_entry_safe() variants Dave Chinner
2023-12-07  2:26   ` Al Viro
2023-12-07  4:18   ` Kent Overstreet
2023-12-06  6:05 ` [PATCH 03/11] vfs: Use dlock list for superblock's inode list Dave Chinner
2023-12-07  2:40   ` Al Viro
2023-12-07  4:59     ` Dave Chinner
2023-12-07  5:03       ` Kent Overstreet
2023-12-06  6:05 ` [PATCH 04/11] lib/dlock-list: Make sibling CPUs share the same linked list Dave Chinner
2023-12-07  4:31   ` Kent Overstreet
2023-12-07  5:42   ` Kent Overstreet
2023-12-07  6:25     ` Dave Chinner
2023-12-07  6:49   ` Al Viro
2023-12-06  6:05 ` [PATCH 05/11] selinux: use dlist for isec inode list Dave Chinner
2023-12-06 21:52   ` Paul Moore
2023-12-06 23:04     ` Dave Chinner
2023-12-07  0:36       ` Paul Moore
2023-12-06  6:05 ` [PATCH 06/11] vfs: factor out inode hash head calculation Dave Chinner
2023-12-07  3:02   ` Al Viro
2023-12-06  6:05 ` Dave Chinner [this message]
2023-12-07  3:05   ` [PATCH 07/11] hlist-bl: add hlist_bl_fake() Al Viro
2023-12-06  6:05 ` [PATCH 08/11] vfs: inode cache conversion to hash-bl Dave Chinner
2023-12-07  4:58   ` Kent Overstreet
2023-12-07  6:03     ` Dave Chinner
2023-12-07  6:42   ` Al Viro
2023-12-06  6:05 ` [PATCH 09/11] hash-bl: explicitly initialise hash-bl heads Dave Chinner
2023-12-07  3:15   ` Al Viro
2023-12-06  6:05 ` [PATCH 10/11] list_bl: don't use bit locks for PREEMPT_RT or lockdep Dave Chinner
2023-12-07  4:16   ` Kent Overstreet
2023-12-07  4:41     ` Dave Chinner
2023-12-06  6:05 ` [PATCH 11/11] hlist-bl: introduced nested locking for dm-snap Dave Chinner
2023-12-07 17:08 ` [PATCH 0/11] vfs: inode cache scalability improvements Kent Overstreet

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