KEYS: Make request_key() and co fundamentally asynchronous

Make request_key() and co fundamentally asynchronous to make it easier for
NFS to make use of them.  There are now accessor functions that do
asynchronous constructions, a wait function to wait for construction to
complete, and a completion function for the key type to indicate completion
of construction.

Note that the construction queue is now gone.  Instead, keys under
construction are linked in to the appropriate keyring in advance, and that
anyone encountering one must wait for it to be complete before they can use
it.  This is done automatically for userspace.

The following auxiliary changes are also made:

 (1) Key type implementation stuff is split from linux/key.h into
     linux/key-type.h.

 (2) AF_RXRPC provides a way to allocate null rxrpc-type keys so that AFS does
     not need to call key_instantiate_and_link() directly.

 (3) Adjust the debugging macros so that they're -Wformat checked even if
     they are disabled, and make it so they can be enabled simply by defining
     __KDEBUG to be consistent with other code of mine.

 (3) Documentation.

[alan@lxorguk.ukuu.org.uk: keys: missing word in documentation]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 23 insertions, 12 deletions

diff --git a/security/keys/internal.h b/security/keys/internal.h
index 1bb416f4bbc..d36d6939335 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -1,6 +1,6 @@
 /* internal.h: authentication token and access key management internal defs
  *
- * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2003-5, 2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
@@ -12,17 +12,28 @@
 #ifndef _INTERNAL_H
 #define _INTERNAL_H
 
-#include <linux/key.h>
+#include <linux/key-type.h>
 #include <linux/key-ui.h>
 
-#if 0
-#define kenter(FMT, a...)	printk("==> %s("FMT")\n",__FUNCTION__ , ## a)
-#define kleave(FMT, a...)	printk("<== %s()"FMT"\n",__FUNCTION__ , ## a)
-#define kdebug(FMT, a...)	printk(FMT"\n" , ## a)
+static inline __attribute__((format(printf, 1, 2)))
+void no_printk(const char *fmt, ...)
+{
+}
+
+#ifdef __KDEBUG
+#define kenter(FMT, ...) \
+	printk(KERN_DEBUG "==> %s("FMT")\n", __FUNCTION__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+	printk(KERN_DEBUG "<== %s()"FMT"\n", __FUNCTION__, ##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+	printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
 #else
-#define kenter(FMT, a...)	do {} while(0)
-#define kleave(FMT, a...)	do {} while(0)
-#define kdebug(FMT, a...)	do {} while(0)
+#define kenter(FMT, ...) \
+	no_printk(KERN_DEBUG "==> %s("FMT")\n", __FUNCTION__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+	no_printk(KERN_DEBUG "<== %s()"FMT"\n", __FUNCTION__, ##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+	no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
 #endif
 
 extern struct key_type key_type_user;
@@ -36,7 +47,7 @@ extern struct key_type key_type_user;
  */
 struct key_user {
 	struct rb_node		node;
-	struct list_head	consq;		/* construction queue */
+	struct mutex		cons_lock;	/* construction initiation lock */
 	spinlock_t		lock;
 	atomic_t		usage;		/* for accessing qnkeys & qnbytes */
 	atomic_t		nkeys;		/* number of keys */
@@ -62,7 +73,7 @@ extern void key_user_put(struct key_user *user);
 extern struct rb_root key_serial_tree;
 extern spinlock_t key_serial_lock;
 extern struct semaphore key_alloc_sem;
-extern struct rw_semaphore key_construction_sem;
+extern struct mutex key_construction_mutex;
 extern wait_queue_head_t request_key_conswq;
 
 
@@ -109,7 +120,7 @@ extern struct key *request_key_and_link(struct key_type *type,
 struct request_key_auth {
 	struct key		*target_key;
 	struct task_struct	*context;
-	const char		*callout_info;
+	char			*callout_info;
 	pid_t			pid;
 };