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/fsclient.c b/fs/afs/fsclient.c
index 9312b92..96f4d76 100644
--- a/fs/afs/fsclient.c
+++ b/fs/afs/fsclient.c
@@ -235,16 +235,15 @@
/*
* deliver reply data to an FS.FetchStatus
*/
-static int afs_deliver_fs_fetch_status(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_fetch_status(struct afs_call *call)
{
struct afs_vnode *vnode = call->reply;
const __be32 *bp;
int ret;
- _enter(",,%u", last);
+ _enter("");
- ret = afs_transfer_reply(call, skb, last);
+ ret = afs_transfer_reply(call);
if (ret < 0)
return ret;
@@ -307,8 +306,7 @@
/*
* deliver reply data to an FS.FetchData
*/
-static int afs_deliver_fs_fetch_data(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_fetch_data(struct afs_call *call)
{
struct afs_vnode *vnode = call->reply;
const __be32 *bp;
@@ -316,7 +314,7 @@
void *buffer;
int ret;
- _enter("{%u},{%u},%d", call->unmarshall, skb->len, last);
+ _enter("{%u}", call->unmarshall);
switch (call->unmarshall) {
case 0:
@@ -332,7 +330,7 @@
* client) */
case 1:
_debug("extract data length (MSW)");
- ret = afs_extract_data(call, skb, last, &call->tmp, 4);
+ ret = afs_extract_data(call, &call->tmp, 4, true);
if (ret < 0)
return ret;
@@ -347,7 +345,7 @@
/* extract the returned data length */
case 2:
_debug("extract data length");
- ret = afs_extract_data(call, skb, last, &call->tmp, 4);
+ ret = afs_extract_data(call, &call->tmp, 4, true);
if (ret < 0)
return ret;
@@ -363,10 +361,10 @@
_debug("extract data");
if (call->count > 0) {
page = call->reply3;
- buffer = kmap_atomic(page);
- ret = afs_extract_data(call, skb, last, buffer,
- call->count);
- kunmap_atomic(buffer);
+ buffer = kmap(page);
+ ret = afs_extract_data(call, buffer,
+ call->count, true);
+ kunmap(buffer);
if (ret < 0)
return ret;
}
@@ -376,8 +374,8 @@
/* extract the metadata */
case 4:
- ret = afs_extract_data(call, skb, last, call->buffer,
- (21 + 3 + 6) * 4);
+ ret = afs_extract_data(call, call->buffer,
+ (21 + 3 + 6) * 4, false);
if (ret < 0)
return ret;
@@ -391,18 +389,15 @@
call->unmarshall++;
case 5:
- ret = afs_data_complete(call, skb, last);
- if (ret < 0)
- return ret;
break;
}
if (call->count < PAGE_SIZE) {
_debug("clear");
page = call->reply3;
- buffer = kmap_atomic(page);
+ buffer = kmap(page);
memset(buffer + call->count, 0, PAGE_SIZE - call->count);
- kunmap_atomic(buffer);
+ kunmap(buffer);
}
_leave(" = 0 [done]");
@@ -515,13 +510,12 @@
/*
* deliver reply data to an FS.GiveUpCallBacks
*/
-static int afs_deliver_fs_give_up_callbacks(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_give_up_callbacks(struct afs_call *call)
{
- _enter(",{%u},%d", skb->len, last);
+ _enter("");
/* shouldn't be any reply data */
- return afs_data_complete(call, skb, last);
+ return afs_extract_data(call, NULL, 0, false);
}
/*
@@ -599,16 +593,15 @@
/*
* deliver reply data to an FS.CreateFile or an FS.MakeDir
*/
-static int afs_deliver_fs_create_vnode(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_create_vnode(struct afs_call *call)
{
struct afs_vnode *vnode = call->reply;
const __be32 *bp;
int ret;
- _enter("{%u},{%u},%d", call->unmarshall, skb->len, last);
+ _enter("{%u}", call->unmarshall);
- ret = afs_transfer_reply(call, skb, last);
+ ret = afs_transfer_reply(call);
if (ret < 0)
return ret;
@@ -696,16 +689,15 @@
/*
* deliver reply data to an FS.RemoveFile or FS.RemoveDir
*/
-static int afs_deliver_fs_remove(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_remove(struct afs_call *call)
{
struct afs_vnode *vnode = call->reply;
const __be32 *bp;
int ret;
- _enter("{%u},{%u},%d", call->unmarshall, skb->len, last);
+ _enter("{%u}", call->unmarshall);
- ret = afs_transfer_reply(call, skb, last);
+ ret = afs_transfer_reply(call);
if (ret < 0)
return ret;
@@ -777,16 +769,15 @@
/*
* deliver reply data to an FS.Link
*/
-static int afs_deliver_fs_link(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_link(struct afs_call *call)
{
struct afs_vnode *dvnode = call->reply, *vnode = call->reply2;
const __be32 *bp;
int ret;
- _enter("{%u},{%u},%d", call->unmarshall, skb->len, last);
+ _enter("{%u}", call->unmarshall);
- ret = afs_transfer_reply(call, skb, last);
+ ret = afs_transfer_reply(call);
if (ret < 0)
return ret;
@@ -863,16 +854,15 @@
/*
* deliver reply data to an FS.Symlink
*/
-static int afs_deliver_fs_symlink(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_symlink(struct afs_call *call)
{
struct afs_vnode *vnode = call->reply;
const __be32 *bp;
int ret;
- _enter("{%u},{%u},%d", call->unmarshall, skb->len, last);
+ _enter("{%u}", call->unmarshall);
- ret = afs_transfer_reply(call, skb, last);
+ ret = afs_transfer_reply(call);
if (ret < 0)
return ret;
@@ -968,16 +958,15 @@
/*
* deliver reply data to an FS.Rename
*/
-static int afs_deliver_fs_rename(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_rename(struct afs_call *call)
{
struct afs_vnode *orig_dvnode = call->reply, *new_dvnode = call->reply2;
const __be32 *bp;
int ret;
- _enter("{%u},{%u},%d", call->unmarshall, skb->len, last);
+ _enter("{%u}", call->unmarshall);
- ret = afs_transfer_reply(call, skb, last);
+ ret = afs_transfer_reply(call);
if (ret < 0)
return ret;
@@ -1072,16 +1061,15 @@
/*
* deliver reply data to an FS.StoreData
*/
-static int afs_deliver_fs_store_data(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_store_data(struct afs_call *call)
{
struct afs_vnode *vnode = call->reply;
const __be32 *bp;
int ret;
- _enter(",,%u", last);
+ _enter("");
- ret = afs_transfer_reply(call, skb, last);
+ ret = afs_transfer_reply(call);
if (ret < 0)
return ret;
@@ -1251,17 +1239,16 @@
/*
* deliver reply data to an FS.StoreStatus
*/
-static int afs_deliver_fs_store_status(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_store_status(struct afs_call *call)
{
afs_dataversion_t *store_version;
struct afs_vnode *vnode = call->reply;
const __be32 *bp;
int ret;
- _enter(",,%u", last);
+ _enter("");
- ret = afs_transfer_reply(call, skb, last);
+ ret = afs_transfer_reply(call);
if (ret < 0)
return ret;
@@ -1443,14 +1430,13 @@
/*
* deliver reply data to an FS.GetVolumeStatus
*/
-static int afs_deliver_fs_get_volume_status(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_get_volume_status(struct afs_call *call)
{
const __be32 *bp;
char *p;
int ret;
- _enter("{%u},{%u},%d", call->unmarshall, skb->len, last);
+ _enter("{%u}", call->unmarshall);
switch (call->unmarshall) {
case 0:
@@ -1460,8 +1446,8 @@
/* extract the returned status record */
case 1:
_debug("extract status");
- ret = afs_extract_data(call, skb, last, call->buffer,
- 12 * 4);
+ ret = afs_extract_data(call, call->buffer,
+ 12 * 4, true);
if (ret < 0)
return ret;
@@ -1472,7 +1458,7 @@
/* extract the volume name length */
case 2:
- ret = afs_extract_data(call, skb, last, &call->tmp, 4);
+ ret = afs_extract_data(call, &call->tmp, 4, true);
if (ret < 0)
return ret;
@@ -1487,8 +1473,8 @@
case 3:
_debug("extract volname");
if (call->count > 0) {
- ret = afs_extract_data(call, skb, last, call->reply3,
- call->count);
+ ret = afs_extract_data(call, call->reply3,
+ call->count, true);
if (ret < 0)
return ret;
}
@@ -1508,8 +1494,8 @@
call->count = 4 - (call->count & 3);
case 4:
- ret = afs_extract_data(call, skb, last, call->buffer,
- call->count);
+ ret = afs_extract_data(call, call->buffer,
+ call->count, true);
if (ret < 0)
return ret;
@@ -1519,7 +1505,7 @@
/* extract the offline message length */
case 5:
- ret = afs_extract_data(call, skb, last, &call->tmp, 4);
+ ret = afs_extract_data(call, &call->tmp, 4, true);
if (ret < 0)
return ret;
@@ -1534,8 +1520,8 @@
case 6:
_debug("extract offline");
if (call->count > 0) {
- ret = afs_extract_data(call, skb, last, call->reply3,
- call->count);
+ ret = afs_extract_data(call, call->reply3,
+ call->count, true);
if (ret < 0)
return ret;
}
@@ -1555,8 +1541,8 @@
call->count = 4 - (call->count & 3);
case 7:
- ret = afs_extract_data(call, skb, last, call->buffer,
- call->count);
+ ret = afs_extract_data(call, call->buffer,
+ call->count, true);
if (ret < 0)
return ret;
@@ -1566,7 +1552,7 @@
/* extract the message of the day length */
case 8:
- ret = afs_extract_data(call, skb, last, &call->tmp, 4);
+ ret = afs_extract_data(call, &call->tmp, 4, true);
if (ret < 0)
return ret;
@@ -1581,8 +1567,8 @@
case 9:
_debug("extract motd");
if (call->count > 0) {
- ret = afs_extract_data(call, skb, last, call->reply3,
- call->count);
+ ret = afs_extract_data(call, call->reply3,
+ call->count, true);
if (ret < 0)
return ret;
}
@@ -1595,26 +1581,17 @@
call->unmarshall++;
/* extract the message of the day padding */
- if ((call->count & 3) == 0) {
- call->unmarshall++;
- goto no_motd_padding;
- }
- call->count = 4 - (call->count & 3);
+ call->count = (4 - (call->count & 3)) & 3;
case 10:
- ret = afs_extract_data(call, skb, last, call->buffer,
- call->count);
+ ret = afs_extract_data(call, call->buffer,
+ call->count, false);
if (ret < 0)
return ret;
call->offset = 0;
call->unmarshall++;
- no_motd_padding:
-
case 11:
- ret = afs_data_complete(call, skb, last);
- if (ret < 0)
- return ret;
break;
}
@@ -1685,15 +1662,14 @@
/*
* deliver reply data to an FS.SetLock, FS.ExtendLock or FS.ReleaseLock
*/
-static int afs_deliver_fs_xxxx_lock(struct afs_call *call,
- struct sk_buff *skb, bool last)
+static int afs_deliver_fs_xxxx_lock(struct afs_call *call)
{
const __be32 *bp;
int ret;
- _enter("{%u},{%u},%d", call->unmarshall, skb->len, last);
+ _enter("{%u}", call->unmarshall);
- ret = afs_transfer_reply(call, skb, last);
+ ret = afs_transfer_reply(call);
if (ret < 0)
return ret;