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KEYS: Make request_key() and co fundamentally asynchronous

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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>
This commit is contained in:
David Howells
2007-10-16 23:29:46 -07:00
committed by Linus Torvalds
parent 398c95bdf2
commit 76181c134f
14 changed files with 604 additions and 434 deletions
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Documentation/keys-request-key.txt
+21 -4
View File
@@ -20,6 +20,19 @@ or:
const char *callout_string,
void *aux);
or:
struct key *request_key_async(const struct key_type *type,
const char *description,
const char *callout_string);
or:
struct key *request_key_async_with_auxdata(const struct key_type *type,
const char *description,
const char *callout_string,
void *aux);
Or by userspace invoking the request_key system call:
key_serial_t request_key(const char *type,
@@ -32,10 +45,14 @@ does not need to link the key to a keyring to prevent it from being immediately
destroyed. The kernel interface returns a pointer directly to the key, and
it's up to the caller to destroy the key.
The request_key_with_auxdata() call is like the in-kernel request_key() call,
except that it permits auxiliary data to be passed to the upcaller (the default
is NULL). This is only useful for those key types that define their own upcall
mechanism rather than using /sbin/request-key.
The request_key*_with_auxdata() calls are like the in-kernel request_key*()
calls, except that they permit auxiliary data to be passed to the upcaller (the
default is NULL). This is only useful for those key types that define their
own upcall mechanism rather than using /sbin/request-key.
The two async in-kernel calls may return keys that are still in the process of
being constructed. The two non-async ones will wait for construction to
complete first.
The userspace interface links the key to a keyring associated with the process
to prevent the key from going away, and returns the serial number of the key to