cifs: multichannel: move channel selection above transport layer

Move the channel (TCP_Server_Info*) selection from the tranport
layer to higher in the call stack so that:

- credit handling is done with the server that will actually be used
  to send.
  * ->wait_mtu_credit
  * ->set_credits / set_credits
  * ->add_credits / add_credits
  * add_credits_and_wake_if

- potential reconnection (smb2_reconnect) done when initializing a
  request is checked and done with the server that will actually be
  used to send.

To do this:

- remove the cifs_pick_channel() call out of compound_send_recv()

- select channel and pass it down by adding a cifs_pick_channel(ses)
  call in:
  - smb311_posix_mkdir
  - SMB2_open
  - SMB2_ioctl
  - __SMB2_close
  - query_info
  - SMB2_change_notify
  - SMB2_flush
  - smb2_async_readv  (if none provided in context param)
  - SMB2_read         (if none provided in context param)
  - smb2_async_writev (if none provided in context param)
  - SMB2_write        (if none provided in context param)
  - SMB2_query_directory
  - send_set_info
  - SMB2_oplock_break
  - SMB311_posix_qfs_info
  - SMB2_QFS_info
  - SMB2_QFS_attr
  - smb2_lockv
  - SMB2_lease_break
    - smb2_compound_op
  - smb2_set_ea
  - smb2_ioctl_query_info
  - smb2_query_dir_first
  - smb2_query_info_comound
  - smb2_query_symlink
  - cifs_writepages
  - cifs_write_from_iter
  - cifs_send_async_read
  - cifs_read
  - cifs_readpages

- add TCP_Server_Info *server param argument to:
  - cifs_send_recv
  - compound_send_recv
  - SMB2_open_init
  - SMB2_query_info_init
  - SMB2_set_info_init
  - SMB2_close_init
  - SMB2_ioctl_init
  - smb2_iotcl_req_init
  - SMB2_query_directory_init
  - SMB2_notify_init
  - SMB2_flush_init
  - build_qfs_info_req
  - smb2_hdr_assemble
  - smb2_reconnect
  - fill_small_buf
  - smb2_plain_req_init
  - __smb2_plain_req_init

The read/write codepath is different than the rest as it is using
pages, io iterators and async calls. To deal with those we add a
server pointer in the cifs_writedata/cifs_readdata/cifs_io_parms
context struct and set it in:

- cifs_writepages      (wdata)
- cifs_write_from_iter (wdata)
- cifs_readpages       (rdata)
- cifs_send_async_read (rdata)

The [rw]data->server pointer is eventually copied to
cifs_io_parms->server to pass it down to SMB2_read/SMB2_write.
If SMB2_read/SMB2_write is called from a different place that doesn't
set the server field it will pick a channel.

Some places do not pick a channel and just use ses->server or
cifs_ses_server(ses). All cifs_ses_server(ses) calls are in codepaths
involving negprot/sess.setup.

- SMB2_negotiate         (binding channel)
- SMB2_sess_alloc_buffer (binding channel)
- SMB2_echo              (uses provided one)
- SMB2_logoff            (uses master)
- SMB2_tdis              (uses master)

(list not exhaustive)

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 19 insertions, 6 deletions

diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 087d5f14320b..71ba74792c9e 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -143,7 +143,9 @@ extern int SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms,
 		     struct smb2_file_all_info *buf,
 		     struct create_posix_rsp *posix,
 		     struct kvec *err_iov, int *resp_buftype);
-extern int SMB2_open_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+extern int SMB2_open_init(struct cifs_tcon *tcon,
+			  struct TCP_Server_Info *server,
+			  struct smb_rqst *rqst,
 			  __u8 *oplock, struct cifs_open_parms *oparms,
 			  __le16 *path);
 extern void SMB2_open_free(struct smb_rqst *rqst);
@@ -151,7 +153,9 @@ extern int SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon,
 		     u64 persistent_fid, u64 volatile_fid, u32 opcode,
 		     bool is_fsctl, char *in_data, u32 indatalen, u32 maxoutlen,
 		     char **out_data, u32 *plen /* returned data len */);
-extern int SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+extern int SMB2_ioctl_init(struct cifs_tcon *tcon,
+			   struct TCP_Server_Info *server,
+			   struct smb_rqst *rqst,
 			   u64 persistent_fid, u64 volatile_fid, u32 opcode,
 			   bool is_fsctl, char *in_data, u32 indatalen,
 			   __u32 max_response_size);
@@ -165,19 +169,25 @@ extern int __SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 			struct smb2_file_network_open_info *pbuf);
 extern int SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 		      u64 persistent_file_id, u64 volatile_file_id);
-extern int SMB2_close_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
-		      u64 persistent_fid, u64 volatile_fid, bool query_attrs);
+extern int SMB2_close_init(struct cifs_tcon *tcon,
+			   struct TCP_Server_Info *server,
+			   struct smb_rqst *rqst,
+			   u64 persistent_fid, u64 volatile_fid,
+			   bool query_attrs);
 extern void SMB2_close_free(struct smb_rqst *rqst);
 extern int SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon,
 		      u64 persistent_file_id, u64 volatile_file_id);
 extern int SMB2_flush_init(const unsigned int xid, struct smb_rqst *rqst,
 			   struct cifs_tcon *tcon,
+			   struct TCP_Server_Info *server,
 			   u64 persistent_file_id, u64 volatile_file_id);
 extern void SMB2_flush_free(struct smb_rqst *rqst);
 extern int SMB2_query_info(const unsigned int xid, struct cifs_tcon *tcon,
 			   u64 persistent_file_id, u64 volatile_file_id,
 			   struct smb2_file_all_info *data);
-extern int SMB2_query_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+extern int SMB2_query_info_init(struct cifs_tcon *tcon,
+				struct TCP_Server_Info *server,
+				struct smb_rqst *rqst,
 				u64 persistent_fid, u64 volatile_fid,
 				u8 info_class, u8 info_type,
 				u32 additional_info, size_t output_len,
@@ -201,6 +211,7 @@ extern int SMB2_query_directory(const unsigned int xid, struct cifs_tcon *tcon,
 				u64 persistent_fid, u64 volatile_fid, int index,
 				struct cifs_search_info *srch_inf);
 extern int SMB2_query_directory_init(unsigned int xid, struct cifs_tcon *tcon,
+				     struct TCP_Server_Info *server,
 				     struct smb_rqst *rqst,
 				     u64 persistent_fid, u64 volatile_fid,
 				     int index, int info_level);
@@ -208,7 +219,9 @@ extern void SMB2_query_directory_free(struct smb_rqst *rqst);
 extern int SMB2_set_eof(const unsigned int xid, struct cifs_tcon *tcon,
 			u64 persistent_fid, u64 volatile_fid, u32 pid,
 			__le64 *eof);
-extern int SMB2_set_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+extern int SMB2_set_info_init(struct cifs_tcon *tcon,
+			      struct TCP_Server_Info *server,
+			      struct smb_rqst *rqst,
 			      u64 persistent_fid, u64 volatile_fid, u32 pid,
 			      u8 info_class, u8 info_type, u32 additional_info,
 			      void **data, unsigned int *size);