Re: [PATCH] fs: pipe/sockets/anon dentries should have themselves as parent

On Fri, Nov 21, 2008 at 06:58:29PM +0100, Eric Dumazet wrote:

+/**
+ * d_alloc_unhashed - allocate unhashed dentry
+ * @inode: inode to allocate the dentry for
+ * @name: dentry name

It's normal to list the parameters in the order they're passed to the
function.  Not sure if we have a tool that checks for this or not --
Randy?

+ *
+ * Allocate an unhashed dentry for the inode given. The inode is
+ * instantiated and returned. %NULL is returned if there is insufficient
+ * memory. Unhashed dentries have themselves as a parent.
+ */
+ 
+struct dentry * d_alloc_unhashed(const char *name, struct inode *inode)
+{
+	struct qstr q = { .name = name, .len = strlen(name) };
+	struct dentry *res;
+
+	res = d_alloc(NULL, &q);
+	if (res) {
+		res->d_sb = inode->i_sb;
+		res->d_parent = res;
+		/*
+		 * We dont want to push this dentry into global dentry hash table.
+		 * We pretend dentry is already hashed, by unsetting DCACHE_UNHASHED
+		 * This permits a working /proc/$pid/fd/XXX on sockets,pipes,anon
+		 */

Line length ... as checkpatch would have warned you ;-)

And there are several other grammatical nitpicks with this comment.  Try
this:

		/*
		 * We don't want to put this dentry in the global dentry
		 * hash table, so we pretend the dentry is already hashed
		 * by unsetting DCACHE_UNHASHED.  This permits 
		 * /proc/$pid/fd/XXX t work for sockets, pipes and
		 * anonymous files (signalfd, timerfd, etc).
		 */

+		res->d_flags &= ~DCACHE_UNHASHED;
+		res->d_flags |= DCACHE_DISCONNECTED;

Is this really better than:

		res->d_flags = res->d_flags & ~DCACHE_UNHASHED |
						DCACHE_DISCONNECTED;

Anyway, nice cleanup.

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."