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>
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index d97552d..5497c84 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -13,7 +13,6 @@
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
-#include <linux/skbuff.h>
#include <linux/rxrpc.h>
#include <linux/key.h>
#include <linux/workqueue.h>
@@ -57,7 +56,7 @@
*/
struct afs_wait_mode {
/* RxRPC received message notification */
- void (*rx_wakeup)(struct afs_call *call);
+ rxrpc_notify_rx_t notify_rx;
/* synchronous call waiter and call dispatched notification */
int (*wait)(struct afs_call *call);
@@ -76,10 +75,8 @@
const struct afs_call_type *type; /* type of call */
const struct afs_wait_mode *wait_mode; /* completion wait mode */
wait_queue_head_t waitq; /* processes awaiting completion */
- void (*async_workfn)(struct afs_call *call); /* asynchronous work function */
struct work_struct async_work; /* asynchronous work processor */
struct work_struct work; /* actual work processor */
- struct sk_buff_head rx_queue; /* received packets */
struct rxrpc_call *rxcall; /* RxRPC call handle */
struct key *key; /* security for this call */
struct afs_server *server; /* server affected by incoming CM call */
@@ -93,6 +90,7 @@
void *reply4; /* reply buffer (fourth part) */
pgoff_t first; /* first page in mapping to deal with */
pgoff_t last; /* last page in mapping to deal with */
+ size_t offset; /* offset into received data store */
enum { /* call state */
AFS_CALL_REQUESTING, /* request is being sent for outgoing call */
AFS_CALL_AWAIT_REPLY, /* awaiting reply to outgoing call */
@@ -100,21 +98,18 @@
AFS_CALL_AWAIT_REQUEST, /* awaiting request data on incoming call */
AFS_CALL_REPLYING, /* replying to incoming call */
AFS_CALL_AWAIT_ACK, /* awaiting final ACK of incoming call */
- AFS_CALL_COMPLETE, /* successfully completed */
- AFS_CALL_BUSY, /* server was busy */
- AFS_CALL_ABORTED, /* call was aborted */
- AFS_CALL_ERROR, /* call failed due to error */
+ AFS_CALL_COMPLETE, /* Completed or failed */
} state;
int error; /* error code */
+ u32 abort_code; /* Remote abort ID or 0 */
unsigned request_size; /* size of request data */
unsigned reply_max; /* maximum size of reply */
- unsigned reply_size; /* current size of reply */
unsigned first_offset; /* offset into mapping[first] */
unsigned last_to; /* amount of mapping[last] */
- unsigned offset; /* offset into received data store */
unsigned char unmarshall; /* unmarshalling phase */
bool incoming; /* T if incoming call */
bool send_pages; /* T if data from mapping should be sent */
+ bool need_attention; /* T if RxRPC poked us */
u16 service_id; /* RxRPC service ID to call */
__be16 port; /* target UDP port */
__be32 operation_ID; /* operation ID for an incoming call */
@@ -129,8 +124,7 @@
/* deliver request or reply data to an call
* - returning an error will cause the call to be aborted
*/
- int (*deliver)(struct afs_call *call, struct sk_buff *skb,
- bool last);
+ int (*deliver)(struct afs_call *call);
/* map an abort code to an error number */
int (*abort_to_error)(u32 abort_code);
@@ -612,27 +606,18 @@
extern int afs_open_socket(void);
extern void afs_close_socket(void);
-extern void afs_data_consumed(struct afs_call *, struct sk_buff *);
extern int afs_make_call(struct in_addr *, struct afs_call *, gfp_t,
const struct afs_wait_mode *);
extern struct afs_call *afs_alloc_flat_call(const struct afs_call_type *,
size_t, size_t);
extern void afs_flat_call_destructor(struct afs_call *);
-extern int afs_transfer_reply(struct afs_call *, struct sk_buff *, bool);
extern void afs_send_empty_reply(struct afs_call *);
extern void afs_send_simple_reply(struct afs_call *, const void *, size_t);
-extern int afs_extract_data(struct afs_call *, struct sk_buff *, bool, void *,
- size_t);
+extern int afs_extract_data(struct afs_call *, void *, size_t, bool);
-static inline int afs_data_complete(struct afs_call *call, struct sk_buff *skb,
- bool last)
+static inline int afs_transfer_reply(struct afs_call *call)
{
- if (skb->len > 0)
- return -EBADMSG;
- afs_data_consumed(call, skb);
- if (!last)
- return -EAGAIN;
- return 0;
+ return afs_extract_data(call, call->buffer, call->reply_max, false);
}
/*