linux/fs/afs
David Howells d001648ec7 rxrpc: Don't expose skbs to in-kernel users [ver #2]
Don't expose skbs to in-kernel users, such as the AFS filesystem, but
instead provide a notification hook the indicates that a call needs
attention and another that indicates that there's a new call to be
collected.

This makes the following possibilities more achievable:

 (1) Call refcounting can be made simpler if skbs don't hold refs to calls.

 (2) skbs referring to non-data events will be able to be freed much sooner
     rather than being queued for AFS to pick up as rxrpc_kernel_recv_data
     will be able to consult the call state.

 (3) We can shortcut the receive phase when a call is remotely aborted
     because we don't have to go through all the packets to get to the one
     cancelling the operation.

 (4) It makes it easier to do encryption/decryption directly between AFS's
     buffers and sk_buffs.

 (5) Encryption/decryption can more easily be done in the AFS's thread
     contexts - usually that of the userspace process that issued a syscall
     - rather than in one of rxrpc's background threads on a workqueue.

 (6) AFS will be able to wait synchronously on a call inside AF_RXRPC.

To make this work, the following interface function has been added:

     int rxrpc_kernel_recv_data(
		struct socket *sock, struct rxrpc_call *call,
		void *buffer, size_t bufsize, size_t *_offset,
		bool want_more, u32 *_abort_code);

This is the recvmsg equivalent.  It allows the caller to find out about the
state of a specific call and to transfer received data into a buffer
piecemeal.

afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction
logic between them.  They don't wait synchronously yet because the socket
lock needs to be dealt with.

Five interface functions have been removed:

	rxrpc_kernel_is_data_last()
    	rxrpc_kernel_get_abort_code()
    	rxrpc_kernel_get_error_number()
    	rxrpc_kernel_free_skb()
    	rxrpc_kernel_data_consumed()

As a temporary hack, sk_buffs going to an in-kernel call are queued on the
rxrpc_call struct (->knlrecv_queue) rather than being handed over to the
in-kernel user.  To process the queue internally, a temporary function,
temp_deliver_data() has been added.  This will be replaced with common code
between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a
future patch.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-01 16:43:27 -07:00
..
afs_cm.h
afs_fs.h
afs_vl.h AFS: Fix silly characters in a comment 2011-07-20 20:48:03 -04:00
afs.h afs: Support interacting with multiple user namespaces 2013-02-13 06:00:51 -08:00
cache.c Fix common misspellings 2011-03-31 11:26:23 -03:00
callback.c workqueue: use mod_delayed_work() instead of cancel + queue 2012-08-13 16:27:37 -07:00
cell.c FS-Cache: Provide the ability to enable/disable cookies 2013-09-27 18:40:25 +01:00
cmservice.c rxrpc: Don't expose skbs to in-kernel users [ver #2] 2016-09-01 16:43:27 -07:00
dir.c afs: switch to ->iterate_shared() 2016-05-10 14:27:44 -04:00
file.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
flock.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
fsclient.c rxrpc: Don't expose skbs to in-kernel users [ver #2] 2016-09-01 16:43:27 -07:00
inode.c don't put symlink bodies in pagecache into highmem 2015-12-08 22:41:36 -05:00
internal.h rxrpc: Don't expose skbs to in-kernel users [ver #2] 2016-09-01 16:43:27 -07:00
Kconfig fs/afs: remove depends on CONFIG_EXPERIMENTAL 2013-01-21 14:39:04 -08:00
main.c afs: Need linux/random.h 2016-08-30 16:07:53 +01:00
Makefile
misc.c kafs: Add more "unified AFS" error codes 2015-04-01 21:36:15 +01:00
mntpt.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
netdevices.c
proc.c convert a bunch of open-coded instances of memdup_user_nul() 2016-01-04 10:26:58 -05:00
rxrpc.c rxrpc: Don't expose skbs to in-kernel users [ver #2] 2016-09-01 16:43:27 -07:00
security.c ->permission() sanitizing: don't pass flags to ->permission() 2011-07-20 01:43:24 -04:00
server.c rxrpc: Provide a way for AFS to ask for the peer address of a call 2016-08-30 16:07:53 +01:00
super.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
vlclient.c rxrpc: Don't expose skbs to in-kernel users [ver #2] 2016-09-01 16:43:27 -07:00
vlocation.c sched, cleanup, treewide: Remove set_current_state(TASK_RUNNING) after schedule() 2014-09-19 12:35:17 +02:00
vnode.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
volume.c fs: introduce f_op->mmap_capabilities for nommu mmap support 2015-01-20 14:02:58 -07:00
write.c remove lots of IS_ERR_VALUE abuses 2016-05-27 15:26:11 -07:00