From d001648ec7cf8b21ae9eec8b9ba4a18295adfb14 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 30 Aug 2016 20:42:14 +0100 Subject: 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 Signed-off-by: David S. Miller --- fs/afs/fsclient.c | 148 +++++++++++++++++++++++------------------------------- 1 file changed, 62 insertions(+), 86 deletions(-) (limited to 'fs/afs/fsclient.c') diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c index 9312b92e54be..96f4d764d1a6 100644 --- a/fs/afs/fsclient.c +++ b/fs/afs/fsclient.c @@ -235,16 +235,15 @@ static void xdr_decode_AFSFetchVolumeStatus(const __be32 **_bp, /* * 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 @@ int afs_fs_fetch_file_status(struct afs_server *server, /* * 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 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call, 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 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call, * 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 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call, /* 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 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call, _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 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call, /* 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 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call, 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 @@ int afs_fs_fetch_data(struct afs_server *server, /* * 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 @@ int afs_fs_give_up_callbacks(struct afs_server *server, /* * 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 @@ int afs_fs_create(struct afs_server *server, /* * 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 @@ int afs_fs_remove(struct afs_server *server, /* * 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 @@ int afs_fs_link(struct afs_server *server, /* * 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 @@ int afs_fs_symlink(struct afs_server *server, /* * 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 @@ int afs_fs_rename(struct afs_server *server, /* * 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 @@ int afs_fs_store_data(struct afs_server *server, struct afs_writeback *wb, /* * 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 @@ int afs_fs_setattr(struct afs_server *server, struct key *key, /* * 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, /* 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, /* 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, /* 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, /* 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, 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 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call, 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 @@ int afs_fs_get_volume_status(struct afs_server *server, /* * 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; -- cgit v1.2.3